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ART001902257
|
oai_dc
|
Modeling and performance evaluation of a piezoelectric energy harvester with segmented electrodes
|
Modeling and performance evaluation of a piezoelectric energy harvester with segmented electrodes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hongyan Wang(Harbin Institute of Technology); Lihua Tang(Nanyang Technological University); Xiaobiao Shan(Harbin Institute of Technology); Tao Xie(Harbin Institute of Technology); Yaowen Yang(Nanyang Technological University)"
] |
Conventional cantilevered piezoelectric energy harvesters (PEHs) are usually fabricated with continuous electrode configuration (CEC), which suffers from the electrical cancellation at higher vibration modes. Though previous research pointed out that the segmented electrode configuration (SEC) can address this issue, a comprehensive evaluation of the PEH with SEC has yet been reported. With the consideration of delivering power to a common load, the AC outputs from all segmented electrode pairs should be rectified to DC outputs separately. In such case, theoretical formulation for power estimation becomes challenging. This paper proposes a method based on equivalent circuit model (ECM) and circuit simulation to evaluate the performance of the PEH with SEC. First, the parameters of the multi-mode ECM are identified from theoretical analysis. The ECM is then established in SPICE software and validated by the theoretical model and finite element method (FEM) with resistive loads. Subsequently, the optimal performances with SEC and CEC are compared considering the practical DC interface circuit. A comprehensive evaluation of the advantageous performance with SEC is provided for the first time. The results demonstrate the feasibility of using SEC as a simple and effective means to improve the performance of a cantilevered PEH at a higher mode.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001902249
|
oai_dc
|
Modal parameters based structural damage detection using artificial neural networks - a review
|
Modal parameters based structural damage detection using artificial neural networks - a review
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.J.S. Hakim(University of Malaya); H. Abdul Razak(University of Malaya)"
] |
One of the most important requirements in the evaluation of existing structural systems and ensuring a safe performance during their service life is damage assessment. Damage can be defined as a weakening of the structure that adversely affects its current or future performance which may cause undesirable displacements, stresses or vibrations to the structure. The mass and stiffness of a structure will change due to the damage, which in turn changes the measured dynamic response of the system. Damage detection can increase safety, reduce maintenance costs and increase serviceability of the structures. Artificial Neural Networks (ANNs) are simplified models of the human brain and evolved as one of the most useful mathematical concepts used in almost all branches of science and engineering. ANNs have been applied increasingly due to its powerful computational and excellent pattern recognition ability for detecting damage in structural engineering. This paper presents and reviews the technical literature for past two decades on structural damage detection using ANNs with modal parameters such as natural frequencies and mode shapes as inputs.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921924
|
oai_dc
|
Reliability analysis of repairable k-out-n system from time response under several times stochastic shocks
|
Reliability analysis of repairable k-out-n system from time response under several times stochastic shocks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yongfeng Fang(Bijie University); Wenliang Tao(Bijie University); Kong Fah Tee(University of Greenwich)"
] |
The model of unit dynamic reliability of repairable k/n (G) system with unit strengthdegradation under repeated random shocks has been developed according to the stress-strength interferencetheory. The unit failure number is obtained based on the unit failure probability which can be computed fromthe unit dynamic reliability. Then, the transfer probability function of the repairable k/n (G) system is givenby its Markov property. Once the transfer probability function has been obtained, the probability densitymatrix and the steady-state probabilities of the system can be retrieved. Finally, the dynamic reliability of therepairable k/n (G) system is obtained by solving the differential equations. It is illustrated that the proposedmethod is practicable, feasible and gives reasonable prediction which conforms to the engineering practice.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921921
|
oai_dc
|
Seismic performance of a rocking bridge pier substructure with frictional hinge dampers
|
Seismic performance of a rocking bridge pier substructure with frictional hinge dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chin-Tung Cheng(National Kaohsiung First Univ. of Sci. & Technol); Fu-Lin Chen(National Kaohsiung First Univ. of Sci. & Technol)"
] |
The rocking pier system (RPS) allows the columns to rock on beam or foundation surfacesduring the attacks of a strong earthquake. Literatures have proved that seismic energy dissipated by the RPSthrough the column impact is limited. To enhance the energy dissipation capacity of a RPS bridgesubstructure, frictional hinge dampers (FHDs) were installed and evaluated by shaking table tests. Thesupplemental FHDs consist of two brass plates sandwiched by three steel plates. The strategy ofself-centering design is to isolate the seismic energy by RPS at the columns and then dissipate the energy byFHDs at the bridge deck. Component tests of FHD were first conducted to verify the friction coefficient anddynamic characteristic of the FHDs. In total, 32 shaking table tests were conducted to investigate parameterssuch as wave forms of the earthquake (El Centro 1940 and Kobe 1995) and normal forces applied on thefriction dampers. An analytical model was also proposed to compare with the tested damping of the bridgesub-structure with or without FHDs.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921922
|
oai_dc
|
Combining smart materials for enhancing intelligent systems: initial studies, success cases and research trends
|
Combining smart materials for enhancing intelligent systems: initial studies, success cases and research trends
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Díaz Lantada(Universidad Politécnica de Madrid); P. Lafont Morgado(Universidad Politécnica de Madrid); J.M. Munoz-Guijosa(Universidad Politécnica de Madrid); J.L. Muñoz Sanz(Universidad Politécnica de Madrid); J. Echávarri Otero(Universidad Politécnica de Madrid); E. Chacón Tanarro(Universidad Politécnica de Madrid); E. De la Guerra Ochoa(Universidad Politécnica de Madrid)"
] |
The combined use of smart materials, complementing each others' characteristics and resultingin devices with optimised features, is providing new solutions in many industries. The use of ingeniouscombinations of smart materials has led to improvements in actuation speed and force, signal-to-noise ratio,sensor precision and unique capabilities such as self-sensing self-healing systems and energy autonomy. Thismay all give rise to a revival for numerous families of smart materials, for which application proposals hadalready reached a stationary situation. It may also provide the boost needed for the definitive industrialsuccess of many others. This study focuses on reviewing the proposals, preliminary studies and successcases related to combining smart materials to obtain multifunctional, improved systems. It also examines themost outstanding applications and fields for the combined use of these smart materials. We will also discussrelated study areas which warrant further research for the development of novel approaches for demandingapplications.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921926
|
oai_dc
|
Influence of sharp stiffness variations in damage evaluation using POD and GSM
|
Influence of sharp stiffness variations in damage evaluation using POD and GSM
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Thiene(University of Padova); U. Galvanetto(University of Padova); C. Surace(Geotechnical and Building Engineering)"
] |
Damage detection methods based on modal analysis have been widely studied in recent years.
However the calculation of mode shapes in real structures can be time consuming and often requiresdedicated software programmes. In the present paper the combined application of proper orthogonaldecomposition and gapped smoothing method to structural damage detection is presented. The first is usedto calculate the dynamic shapes of a damaged structural element using only the time response of the systemwhile the second is used to derive a reference baseline to which compare the data coming from the damagedstructure. Experimental verification is provided for a beam case while numerical analyses are conducted onplates. The introduction of a stiffener on a plate is investigated and a method to distinguish its influence fromthat of a defect is presented. Results highlight that the derivatives of the proper orthogonal modes are moreeffective damage indices than the modes themselves and that they can be used in damage detection whenonly data from the damaged structure are available. Furthermore the stiffened plate case shows how thesimple use of the curvature is not sufficient when analysing complex components. The combined applicationof the two techniques provides a possible improvement in damage detection of typical aeronauticalstructures.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921931
|
oai_dc
|
Validation of a smart structural concept for wing-flap camber morphing
|
Validation of a smart structural concept for wing-flap camber morphing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rosario Pecora(University of Naples “Federico II”, Via Claudio); Francesco Amoroso(University of Naples “Federico II”, Via Claudio); Gianluca Amendola(University of Naples “Federico II”, Via Claudio); Antonio Concilio(Italian Aerospace Research Center)"
] |
The study is aimed at investigating the feasibility of a high TRL solution for a wing flap segment characterized by morphable camber airfoil and properly tailored to be implemented on a real-scale regional transportation aircraft. On the base of specific aerodynamic requirements in terms of target airfoil shapes and related external loads, the structural layout of the device was preliminarily defined. Advanced FE analyses were then carried out in order to properly size the load-carrying structure and the embedded actuation system. A full scale limited span prototype was finally manufactured and tested to: • demonstrate the morphing capability of the conceived structural layout; • demonstrate the capability of the morphing structure to withstand static loads representative of the limit aerodynamic pressures expected in service; • characterize the dynamic behavior of the morphing structure through the identification of the most significant normal modes. Obtained results showed high correlation levels with respect to numerical expectations thus proving the compliance of the device with the design requirements as well as the goodness of modeling approaches implemented during the design phase.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921923
|
oai_dc
|
Design and investigation of a shape memory alloy actuated gripper
|
Design and investigation of a shape memory alloy actuated gripper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Krishna Chaitanya(Vignan's University); K. Dhanalakshmi(National Institute of Technology)"
] |
This paper proposes a new design of shape memory alloy (SMA) wire actuated gripper for open mode operation. SMA can generate smooth muscle movements during actuation which make them potentially good contenders in designing grippers. The principle of the shape memory alloy gripper is to convert the linear displacement of the SMA wire actuator into the angular displacement of the gripping jaw. Steady state analysis is performed to design the wire diameter of the bias spring for a known SMA wire. The gripper is designed to open about an angle of 22.5 when actuated using pulsating electric current from a constant current source. The safe operating power range of the gripper is determined and verified theoretically. Experimental evaluation for the uncontrolled gripper showed a rotation of 19.97. Forced cooling techniques were employed to speed up the cooling process. The gripper is simple and robust in design (single movable jaw), easy to fabricate, low cost, and exhibits wide handling capabilities like longer object handling time and handling wide sizes of objects with minimum utilization of power since power is required only to grasp and release operations.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921932
|
oai_dc
|
Multiscale features and information extraction of online strain for long-span bridges
|
Multiscale features and information extraction of online strain for long-span bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Baijian Wu(Southeast University); Zhaoxia Li(Southeast University); Tommy H.T. Chan(Queensland University of Technology); Ying Wang(Southeast University)"
] |
The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of 105, 102 and 100 sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of 10-2, 10-1 and 100 Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921927
|
oai_dc
|
A case study of damage detection in four-bays steel structures using the HHT approach
|
A case study of damage detection in four-bays steel structures using the HHT approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Ko Hsu(National Central University); Cheng-Wu Chen(National Kaohsiung Marine University); Dung-Jiang Chiou(National Central University); Ming-Yi Liu(Chung Yuan University); Wei-Ling Chiang (National Central University); Pei-Chiung Huang(National Central University)"
] |
This study aims to investigate the relationship between structural damage and sensitivity indices using the Hilbert-Huang transform (HHT) method. Two damage detection indices are proposed: the ratio of bandwidth (RB), and the ratio of effective stiffness (RES). The nonlinear four bays multiple degree of freedom models with various predominant frequencies are constructed using the SAP2000 program. Adjusted PGA earthquake data (Japan 311, Chi-Chi 921) are used as the excitations. Next, the damage detection indices obtained using the HHT and the fast Fourier transform (FFT) methods are evaluated based on the acceleration responses of the structures to earthquakes. Simulation results indicate that, the column of the 1st floor is the first yielding position and the RB value is changed when the RES<90% in all cases. Moreover, the RB value of the 1st floor changes more sensitive than those from the top floor. In addition, when the structural response is nonlinear (i.e., RES<100%), the RB and the RES curves indicate the incremental change in the HHT spectra. However, the same phenomenon can be found from FFT spectra only when the stiffness reduction is large enough. Therefore, the RB estimated from the smoothed HHT spectra is an effective and sensitive index for detecting structural damage.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921933
|
oai_dc
|
Extension of indirect displacement estimation method using acceleration and strain to various types of beam structures
|
Extension of indirect displacement estimation method using acceleration and strain to various types of beam structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"조수진(울산과학기술원); 심성한(울산과학기술원); 이준화(울산과학기술대학교); 박종웅(University of Illinois at Urbana - Champaign)"
] |
extended to various types of beam structures beyond the previous validation on the prismatic or near-prismatic beams. By fusing different types of responses, the IDEAS method is able to estimate displacements containing pseudo-static components with high frequency noise to be significantly reduced. However, the concerns to the IDEAS method come from possible disagreement of the assumed sinusoidal mode shapes to the actual mode shapes, which allows the IDEAS method to be valid only for simply-supported prismatic beams and limits its applicability to real world problems. In this paper, the extension of the IDEAS method to the general types of beams is investigated by the mathematical formulation of the modal mapping matrix only for the monitored substructure, so-called monitoring span. The formulation particularly considers continuous and wide beams to extend the IDEAS method to general beam structures that reflect many real bridges. Numerical simulations using four types of beams with various irregularities are presented to show the effectiveness and accuracy of the IDEAS method in estimating displacements.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921929
|
oai_dc
|
Servo control of an under actuated system using antagonistic shape memory alloy
|
Servo control of an under actuated system using antagonistic shape memory alloy
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Sunjai Nakshatharan(National Institute of Technology); K. Dhanalakshmi(National Institute of Technology); D. Josephine Selvarani Ruth(National Institute of Technology)"
] |
This paper presents the design, modelling and, simulation and experimental results of a shape memory alloy (SMA) actuator based critical motion control application. Dynamic performance of SMA and its ability in replacing servo motor is studied for which the famous open loop unstable balancing ball and beam system direct driven by antagonistic SMA is designed and developed. Simulation uses the mathematical model of ball and beam structure derived from the first principles and model estimated for the SMA actuator by system identification. A PID based cascade control system consisting of two loops is designed and control of ball trajectory for various target positions with settling time as control parameter is verified experimentally. The results demonstrate the performance of SMA for a complicated i.e., under actuated, highly nonlinear unstable system, and thereby it\'s dynamic behaviour. Control strategies bring out the effectiveness of the actuator and its possible application to much more complex applications such as in aerospace control and robotics.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921934
|
oai_dc
|
Automated assessment of cracks on concrete surfaces using adaptive digital image processing
|
Automated assessment of cracks on concrete surfaces using adaptive digital image processing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yufei Liu (Tsinghua University); 조수진(울산과학기술원); Jiansheng Fan(Tsinghua University); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign)"
] |
Monitoring surface cracks is important to ensure the health of concrete structures. However, traditional visual inspection to monitor the concrete cracks has disadvantages such as subjective inspection nature, associated time and cost, and possible danger to inspectors. To alter the visual inspection, a complete procedure for automated crack assessment based on adaptive digital image processing has been proposed in this study. Crack objects are extracted from the images using the subtraction with median filter and the local binarization using the Niblack\' s method. To adaptively determine the optimal window sizes for the median filter and the Niblack\' s method without distortion of crack object, an optimal filter size index (OFSI) is proposed. From the extracted crack objects using the optimal size of window, the crack objects are decomposed to the crack skeletons and edges, and the crack width is calculated using 4-connected normal line according to the orientation of the local skeleton line. For an image, a crack width nephogram is obtained to have an intuitive view of the crack distribution. The proposed procedure is verified from a test on a concrete reaction wall with various types of cracks. From the crack images with different crack widths and patterns, the widths of cracks in the order of submillimeters are calculated with high accuracy.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001921928
|
oai_dc
|
Energy efficiency strategy for a general real-time wireless sensor platform
|
Energy efficiency strategy for a general real-time wireless sensor platform
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"ZhiCong Chen(Fuzhou University)"
] |
The energy constraint is still a common issue for the practical application of wireless sensors, since they are usually powered by batteries which limit their lifetime. In this paper, a practical compound energy efficiency strategy is proposed and realized in the implementation of a real time wireless sensor platform. The platform is intended for wireless structural monitoring applications and consists of three parts, wireless sensing unit, base station and data acquisition and configuration software running in a computer within the Matlab environment. The high energy efficiency of the wireless sensor platform is achieved by a proposed adaptive radio transmission power control algorithm, and some straightforward methods, including adopting low power ICs and high efficient power management circuits, low duty cycle radio polling and switching off radio between two adjacent data packets\' transmission. The adaptive transmission power control algorithm is based on the statistical average of the path loss estimations using a moving average filter. The algorithm is implemented in the wireless node and relies on the received signal strength feedback piggybacked in the ACK packet from the base station node to estimate the path loss. Therefore, it does not need any control packet overheads. Several experiments are carried out to investigate the link quality of radio channels, validate and evaluate the proposed adaptive transmission power control algorithm, including static and dynamic experiments.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145446
|
oai_dc
|
Piezoelectric impedance based damage detection in truss bridges based on time frequency ARMA model
|
Piezoelectric impedance based damage detection in truss bridges based on time frequency ARMA model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xingyu Fan(Curtin University); Jun LI(Curtin University); Hong Hao(Curtin University)"
] |
Electromechanical impedance (EMI) based structural health monitoring is performed by measuring the variation in the impedance due to the structural local damage. The impedance signals are acquired from the piezoelectric patches that are bonded on the structural surface. The impedance variation, which is directly related to the mechanical properties of the structure, indicates the presence of local structural damage. Two traditional EMI-based damage detection methods are based on calculating the difference between the measured impedance signals in the frequency domain from the baseline and the current structures. In this paper, a new structural damage detection approach by analyzing the time domain impedance responses is proposed. The measured time domain responses from the piezoelectric transducers will be used for analysis. With the use of the Time Frequency Autoregressive Moving Average (TFARMA) model, a damage index based on Singular Value Decomposition (SVD) is defined to identify the existence of the structural local damage. Experimental studies on a space steel truss bridge model in the laboratory are conducted to verify the proposed approach. Four piezoelectric transducers are attached at different locations and excited by a sweep-frequency signal. The impedance responses at different locations are analyzed with TFARMA model to investigate the effectiveness and performance of the proposed approach. The results demonstrate that the proposed approach is very sensitive and robust in detecting the bolt damage in the gusset plates of steel truss bridges.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145451
|
oai_dc
|
Surface flatness and distortion inspection of precast concrete elements using laser scanning technology
|
Surface flatness and distortion inspection of precast concrete elements using laser scanning technology
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jack C.P. Cheng(The Hong Kong University of Science and Technology); Qian Wang(The Hong Kong University of Science and Technology); 김민구(충북대학교); Hoon Sohn(Korea Advanced Institute of Science and)"
] |
Precast concrete elements are widely used in the construction of buildings and civil infrastructures as they provide higher construction quality and requires less construction time. However, any abnormalities in precast concrete surfaces such as non-flatness or distortion, can influence the erection of the elements as well as the functional performance of the connections between elements. Thus, it is important to undertake surface flatness and distortion inspection (SFDI) on precast concrete elements before their delivery to the construction sites. The traditional methods of SFDI which are conducted manually or by contact-type devices are, however, time-consuming, labor-intensive and error-prone. To tackle these problems, this study proposes techniques for SFDI of precast concrete elements using laser scanning technology. The proposed techniques estimate the FF number to evaluate the surface flatness, and estimate three different measurements, warping, bowing, and differential elevation between adjacent elements, to evaluate the surface distortion. The proposed techniques were validated by experiments on four small scale test specimens manufactured by a 3D printer. The measured surface flatness and distortion from the laser scanned data were compared to the actual ones, which were obtained from the designed surface geometries of the specimens. The validation experiments show that the proposed techniques can evaluate the surface flatness and distortion effectively and accurately. Furthermore, scanning experiments on two actual precast concrete bridge deck panels were conducted and the proposed techniques were successfully applied to the scanned data of the panels.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145440
|
oai_dc
|
Optimal layout of long-gauge sensors for deformation distribution identification
|
Optimal layout of long-gauge sensors for deformation distribution identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jian Zhang(Southeast University); Qingqing Zhang(Southeast University); Qi Xia(Southeast University); Zhishen Wu(Southeast University)"
] |
Structural deflection can be identified from measured strains from long gague sensors, but the sensor layout scheme greatly influences on the accuracy of identified resutls. To determine the optimal sensor layout scheme for accurate deflection identification of the tied arch bridge, the method of optimal layout of long-gauge fiber optic sensors is studied, in which the characteristic curve is first developed by using the bending macro-strain curve under multiple target load conditions, then optimal sensor layout scheme with different number of sensors are determined. A tied arch bridge is studied as an example to verify the effectiveness and robustness of the proposed method for static and dynamic deflection identification.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145450
|
oai_dc
|
Force monitoring of steel cables using vision-based sensing technology: methodology and experimental verification
|
Force monitoring of steel cables using vision-based sensing technology: methodology and experimental verification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.W. Ye(Zhejiang University); C.Z. Dong(Zhejiang University); T. Liu(Zhejiang University)"
] |
Steel cables serve as the key structural components in long-span bridges, and the force state of the steel cable is deemed to be one of the most important determinant factors representing the safety condition of bridge structures. The disadvantages of traditional cable force measurement methods have been envisaged and development of an effective alternative is still desired. In the last decade, the vision-based sensing technology has been rapidly developed and broadly applied in the field of structural health monitoring (SHM). With the aid of vision-based multi-point structural displacement measurement method, monitoring of the tensile force of the steel cable can be realized. In this paper, a novel cable force monitoring system integrated with a multi-point pattern matching algorithm is developed. The feasibility and accuracy of the developed vision-based force monitoring system has been validated by conducting the uniaxial tensile tests of steel bars, steel wire ropes, and parallel strand cables on a universal testing machine (UTM) as well as a series of moving loading experiments on a scale arch bridge model. The comparative study of the experimental outcomes indicates that the results obtained by the vision-based system are consistent with those measured by the traditional method for cable force measurement.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145439
|
oai_dc
|
Data fusion based improved Kalman filter with unknown inputs and without collocated acceleration measurements
|
Data fusion based improved Kalman filter with unknown inputs and without collocated acceleration measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ying Lei(Xiamen University); Sujuan Luo(Xiamen University); Ying Su(Xiamen University)"
] |
The classical Kalman filter (KF) can provide effective state estimation for structural identification and vibration control, but it is applicable only when external inputs are measured. So far, some studies of Kalman filter with unknown inputs (KF-UI) have been proposed. However, previous KF-UI approaches based solely on acceleration measurements are inherently unstable which leads to poor tracking and fictitious drifts in the identified structural displacements and unknown inputs in the presence of measurement noises. Moreover, it is necessary to have the measurements of acceleration responses at the locations where unknown inputs applied, i.e., with collocated acceleration measurements in these approaches. In this paper, it aims to extend the classical KF approach to circumvent the above limitations for general real time estimation of structural state and unknown inputs without using collocated acceleration measurements. Based on the scheme of the classical KF, an improved Kalman filter with unknown excitations (KF-UI) and without collocated acceleration measurements is derived. Then, data fusion of acceleration and displacement or strain measurements is used to prevent the drifts in the identified structural state and unknown inputs in real time. Such algorithm is not available in the literature. Some numerical examples are used to demonstrate the effectiveness of the proposed approach.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145441
|
oai_dc
|
Concrete pavement monitoring with PPP-BOTDA distributed strain and crack sensors
|
Concrete pavement monitoring with PPP-BOTDA distributed strain and crack sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Genda Chen(Missouri University of Science and Technology); Yi Bao(Missouri University); Fujian Tang(Missouri University); Yizheng Chen (Missouri University); Weina Meng(Missouri University); Ying Huang(North Dakota State University)"
] |
In this study, the feasibility of using telecommunication single-mode optical fiber (SMF) as a distributed fiber optic strain and crack sensor was evaluated in concrete pavement monitoring. Tensile tests on various sensors indicated that the SMF-28e+ fiber revealed linear elastic behavior to rupture at approximately 26 N load and 2.6% strain. Six full-scale concrete panels were prepared and tested under truck and three-point loads to quantify the performance of sensors with pulse pre-pump Brillouin optical time domain analysis (PPP-BOTDA). The sensors were protected by precast mortar from brutal action during concrete casting. Once air-cured for 2 hours after initial setting, half a mortar cylinder of 12 mm in diameter ensured that the protected sensors remained functional during and after concrete casting. The strains measured from PPP-BOTDA with a sensitivity coefficient of 5.43 10-5 GHz/ were validated locally by commercial fiber Bragg grating (FBG) sensors. Unlike the point FBG sensors, the distributed PPP-BOTDA sensors can be utilized to effectively locate multiple cracks. Depending on their layout, the distributed sensors can provide one- or two-dimensional strain fields in pavement panels. The width of both micro and major cracks can be linearly related to the peak strain directly measured with the distributed fiber optic sensor.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145443
|
oai_dc
|
Electromagnetic energy harvesting from structural vibrations during earthquakes
|
Electromagnetic energy harvesting from structural vibrations during earthquakes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Songye Zhu(The Hong Kong Polytechnic University); Wenai Shen(Huazhong University of Science and Technology); Hong-Ping Zhu(Huazhong University of Science & Technology); You-Lin Xu(The Hong Kong Polytechnic University)"
] |
Energy harvesting is an emerging technique that extracts energy from surrounding environments to power low-power devices. For example, it can potentially provide sustainable energy for wireless sensing networks (WSNs) or structural control systems in civil engineering applications. This paper presents a comprehensive study on harvesting energy from earthquake-induced structural vibrations, which is typically of low frequency, to power WSNs. A macroscale pendulum-type electromagnetic harvester (MPEH) is proposed, analyzed and experimentally validated. The presented predictive model describes output power dependence with mass, efficiency and the power spectral density of base acceleration, providing a simple tool to estimate harvested energy. A series of shaking table tests in which a single-storey steel frame model equipped with a MPEH has been carried out under earthquake excitations. Three types of energy harvesting circuits, namely, a resistor circuit, a standard energy harvesting circuit (SEHC) and a voltage-mode controlled buck-boost converter were used for comparative study. In ideal cases, i.e., resistor circuit cases, the maximum electric energy of 8.72 J was harvested with the efficiency of 35.3%. In practical cases, the maximum electric energy of 4.67 J was extracted via the buck-boost converter under the same conditions. The predictive model on output power and harvested energy has been validated by the test data.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145445
|
oai_dc
|
Measurement of rivulet movement and thickness on inclined cable using videogrammetry
|
Measurement of rivulet movement and thickness on inclined cable using videogrammetry
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yong Xia(The Hong Kong Polytechnic University); Haiquan Jing(The Hong Kong Polytechnic University); You-Lin Xu(Hong Kong Polytechnic University); Yong-Le Li(Southwest Jiaotong University)"
] |
Stay cables in some cable-stayed bridges suffer large amplitude vibrations under the simultaneous occurrence of rain and wind. This phenomenon is called rain–wind-induced vibration (RWIV). The upper rivulet oscillating circumferentially on the inclined cable surface plays an important role in this phenomenon. However, its small size and high sensitivity to wind flow make measuring rivulet size and its movement challenging. Moreover, the distribution of the rivulet along the entire cable has not been measured. This paper applies the videogrammetric technique to measure the movement and geometry dimension of the upper rivulet along the entire cable during RWIV. A cable model is tested in an open-jet wind tunnel with artificial rain. RWIV is successfully reproduced. Only one digital video camera is employed and installed on the cable during the experiment. The camera records video clips of the upper rivulet and cable movements. The video clips are then transferred into a series of images, from which the positions of the cable and the upper rivulet at each time instant are identified by image processing. The thickness of the upper rivulet is also estimated. The oscillation amplitude, equilibrium position, and dominant frequency of the rivulet are presented. The relationship between cable and rivulet variations is also investigated. Results demonstrate that this non-contact, non-intrusive measurement method has good resolution and is cost effective.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145447
|
oai_dc
|
Identification of failure mechanisms for CFRP-confined circular concrete-filled steel tubular columns through acoustic emission signals
|
Identification of failure mechanisms for CFRP-confined circular concrete-filled steel tubular columns through acoustic emission signals
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yanlei Wang(Dalian University of Technology); Dong-Sheng Li(Dalian University of Technology); Fangzhu Du(Dalian University of Technology); Zhi Chen(Dalian University of Technology)"
] |
The CFRP-confined circular concrete-filled steel tubular column is composed of concrete, steel, and CFRP. Its failure mechanics are complex. The most important difficulties are lack of an available method to establish a relationship between a specific damage mechanism and its acoustic emission (AE) characteristic parameter. In this study, AE technique was used to monitor the evolution of damage in CFRP-confined circular concrete-filled steel tubular columns. A fuzzy c-means method was developed to determine the relationship between the AE signal and failure mechanisms. Cluster analysis results indicate that the main AE sources include five types: matrix cracking, debonding, fiber fracture, steel buckling, and concrete crushing. This technology can not only totally separate five types of damage sources, but also make it easier to judge the damage evolution process. Furthermore, typical damage waveforms were analyzed through wavelet analysis based on the cluster results, and the damage modes were determined according to the frequency distribution of AE signals.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145448
|
oai_dc
|
The effect of non-synchronous sensing on structural identification and its correction
|
The effect of non-synchronous sensing on structural identification and its correction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhouquan Feng(The Hong Kong University of Science and Technology); Lambros Katafygiotis(Hong Kong University of Science and Technology)"
] |
The goal of this study is to investigate the effect of non-synchronous sensing when using wireless sensors on structural identification and to attempt correcting such errors in order to obtain a better identification result. The sources causing non-synchronous sensing are discussed first and the magnitudes of such synchronization errors are estimated based on time stamps of data samples collected from Imote2 sensors; next the impact of synchronization errors on power spectral densities (PSDs) and correlation functions of output responses are derived analytically; finally a new method is proposed to correct such errors. In this correction method, the corrected PSDs of output responses are estimated using non-synchronous samples based on a modified FFT. The effect of synchronization errors in the measured output responses on structural identification and the application of this correction method are demonstrated using simulation examples. The simulation results show that even small synchronization errors in the output responses can distort the identified modal and stiffness parameters remarkably while the parameters identified using the proposed correction method can achieve high accuracy.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145449
|
oai_dc
|
Stochastic modelling and optimum inspection and maintenance strategy for fatigue affected steel bridge members
|
Stochastic modelling and optimum inspection and maintenance strategy for fatigue affected steel bridge members
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hua-Peng Chen(University of Greenwich); Tian-Li Huang(University of Greenwich); Hao Zhou(Central South University); Wei-Xin Ren(Central South University)"
] |
This paper presents a method for stochastic modelling of fatigue crack growth and optimising inspection and maintenance strategy for the structural members of steel bridges. The fatigue crack evolution is considered as a stochastic process with uncertainties, and the Gamma process is adopted to simulate the propagation of fatigue crack in steel bridge members. From the stochastic modelling for fatigue crack growth, the probability of failure caused by fatigue is predicted over the service life of steel bridge members. The remaining fatigue life of steel bridge members is determined by comparing the fatigue crack length with its predetermined threshold. Furthermore, the probability of detection is adopted to consider the uncertainties in detecting fatigue crack by using existing damage detection techniques. A multi-objective optimisation problem is proposed and solved by a genetic algorithm to determine the optimised inspection and maintenance strategy for the fatigue affected steel bridge members. The optimised strategy is achieved by minimizing the life-cycle cost, including the inspection, maintenance and failure costs, and maximizing the service life after necessary intervention. The number of intervention during the service life is also taken into account to investigate the relationship between the service life and the cost for maintenance. The results from numerical examples show that the proposed method can provide a useful approach for cost-effective inspection and maintenance strategy for fatigue affected steel bridges.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145452
|
oai_dc
|
Experimental validation of smartphones for measuring human-induced loads
|
Experimental validation of smartphones for measuring human-induced loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jun Chen(Tongji University); Huan Tan(Tongji University); Ziye Pan(Tongji University)"
] |
The rapid technology developments in smartphones have created a significant opportunity for their use in structural live load measurements. This paper presents extensive experiments conducted in two stages to investigate this opportunity. Shaking table tests were carried out in the first stage using selected popular smartphones to measure the sinusoidal waves of various frequencies, the sinusoidal sweeping, and earthquake waves. Comparison between smartphone measurements and real inputs showed that the smartphones used in this study gave reliable measurements for harmonic waves in both time and frequency domains. For complex waves, smartphone measurements should be used with caution. In the second stage, three-dimensional motion capture technology was employed to explore the capacity of smartphones for measuring the movement of individuals in walking, bouncing and jumping activities. In these tests, reflective markers were attached to the test subject. The markers\' trajectories were recorded by the motion capture system and were taken as references. The smartphone measurements agreed well with the references when the phone was properly fixed. Encouraged by these experimental validation results, smartphones were attached to moving participants of this study. The phones measured the acceleration near the center-of-mass of his or her body. The human-induced loads were then reconstructed by the acceleration measurements in conjunction with a biomechanical model. Satisfactory agreement between the reconstructed forces and that measured by a force plate was observed in several instances, clearly demonstrating the capability of smartphones to accurately assist in obtaining human-induced load measurements.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145442
|
oai_dc
|
A new swarm intelligent optimization algorithm: Pigeon Colony Algorithm (PCA)
|
A new swarm intelligent optimization algorithm: Pigeon Colony Algorithm (PCA)
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology); Kai-Fang Wen(Dalian University); Hong-Nan Li(Dalian University of Technology)"
] |
In this paper, a new Pigeon Colony Algorithm (PCA) based on the features of a pigeon colony flying is proposed for solving global numerical optimization problems. The algorithm mainly consists of the take-off process, flying process and homing process, in which the take-off process is employed to homogenize the initial values and look for the direction of the optimal solution; the flying process is designed to search for the local and global optimum and improve the global worst solution; and the homing process aims to avoid having the algorithm fall into a local optimum. The impact of parameters on the PCA solution quality is investigated in detail. There are low-dimensional functions, high-dimensional functions and systems of nonlinear equations that are used to test the global optimization ability of the PCA. Finally, comparative experiments between the PCA, standard genetic algorithm and particle swarm optimization were performed. The results showed that PCA has the best global convergence, smallest cycle indexes, and strongest stability when solving high-dimensional, multi-peak and complicated problems.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002145444
|
oai_dc
|
Sensing properties of optical fiber sensor to ultrasonic guided waves
|
Sensing properties of optical fiber sensor to ultrasonic guided waves
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wensong Zhou(Harbin Institute of Technology); Hui Li(Harbin Institute of Technology); Yongkang Dong(Harbin Institute of Technology); Anbang Wang(Harbin Institute of Technology)"
] |
Abstract Optical fiber sensors have been proven that they have the potential to detect high-frequency ultrasonic signals, in structural health monitoring field which generally refers to acoustic emission signals from active structural damages and guided waves excited by ultrasonic actuators and propagating in waveguide. In this work, the sensing properties of optical fiber sensors based on Mach-Zehnder interferometer were investigated in the metal plate. Analytical formulas were conducted first to explore the parameters affecting its sensing performances. Due to the simple and definable frequency component, the Lamb wave excited by the piezoelectric wafer was employed to study the sensitivity of the proposed optical fiber sensors with respect to the frequency, rather than the acoustic emission signals. In the experiments, according to above investigations, spiral shape optical fiber sensors with different size were selected to increase their sensitivity. Lamb waves were excited by a circular piezoelectric wafer, while another piezoelectric wafer was used to compare their voltage responses. Furthermore, by changing the excitation frequency, the tuning frequency characteristic of the proposed optical fiber sensor was also investigated experimentally.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056315
|
oai_dc
|
Damage detection in structural beam elements using hybrid neuro fuzzy systems
|
Damage detection in structural beam elements using hybrid neuro fuzzy systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kamil Aydin(Erciyes University); Ozgur Kisi(Canik Basari University)"
] |
A damage detection algorithm based on neuro fuzzy hybrid system is presented in this study for location and severity predictions of cracks in beam-like structures. A combination of eigenfrequencies and rotation deviation curves are utilized as input to the soft computing technique. Both single and multiple damage cases are considered. Theoretical expressions leading to modal properties of damaged beam elements are provided. The beam formulation is based on Euler-Bernoulli theory. The cracked section of beam is simulated employing discrete spring model whose compliance is computed from stress intensity factors of fracture mechanics. A hybrid neuro fuzzy technique is utilized to solve the inverse problem of crack identification. Two different neuro fuzzy systems including grid partitioning (GP) and subtractive clustering (SC) are investigated for the highlighted problem. Several error metrics are utilized for evaluating the accuracy of the hybrid algorithms. The study is the first in terms of 1) using the two models of neuro fuzzy systems in crack detection and 2) considering multiple damages in beam elements employing the fused neuro fuzzy procedures. At the end of the study, the developed hybrid models are tested by utilizing the noise-contaminated data. Considering the robustness of the models, they can be employed as damage identification algorithms in health monitoring of beam-like structures
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056308
|
oai_dc
|
An application of operational deflection shapes and spatial filtration for damage detection
|
An application of operational deflection shapes and spatial filtration for damage detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Krzysztof Mendrok(AGH University of Science and Technology); Jeremi Wójcicki(AGH University of Science and Technology); Tadeusz Uhl(AGH University of Science and Technology)"
] |
In the paper, the authors propose the application of operational deflection shapes (ODS) for the detection of structural changes in technical objects. The ODS matrix is used to formulate the spatial filter that is further used for damage detection as a classical modal filter (Meirovitch and Baruh 1982, Zhang et al. 1990). The advantage of the approach lies in the fact that no modal analysis is required, even on the reference spatial filter formulation and other components apart from structural ones can be filtered (e.g. harmonics of rotational velocity). The proposed methodology was tested experimentally on a laboratory stand, a frame-like structure, excited from two sources: an impact hammer, which provided a wide-band excitation of all modes, and an electro-dynamic shaker, which simulated a harmonic component in the output spectra. The damage detection capabilities of the proposed method were tested by changing the structural properties of the model and comparing the results with the original ones. The quantitative assessment of damage was performed by employing a damage index (DI) calculation. Comparison of the output of the ODS filter and the classical modal filter is also presented and analyzed in the paper. The closing section of the paper describes the verification of the method on a real structure – a road viaduct.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056310
|
oai_dc
|
The effect of arch geometry on the structural behavior of masonry bridges
|
The effect of arch geometry on the structural behavior of masonry bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet C. Altunisik(Karadeniz Technical University); Burcu Kanbur(Karadeniz Technical University); Ali F. Genc(Karadeniz Technical University)"
] |
Arch bridges consist of some important components for structural behavior such as arches, sidewalls, filling materials and foundations. But, arches are the most important part for this type of bridges. For this reason, investigation of arch is come into prominence. In this paper, it is aimed to investigate the arch thickness effect on the structural behavior of masonry arch bridges. For this purpose, Göderni historical arch bridge which was located in Kulp town, Diyarbakir Turkey and the bridge restoration process has still continued is selected as an application. The construction year of the bridge is not fully known, but the date is estimated to be the second half of the 19th century. The bridge has two arches with the 0.52 cm and 0.69 cm arch thickness, respectively. Finite element model of the bridge is constructed with ANSYS software to reflect the current situation using relievo drawings. Then the arch thickness is changed by increasing and decreasing respectively and finite element models are reconstructed. The structural responses of the bridge are obtained for all arch thickness under dead load and live load. Maximum displacements, maximum-minimum principal stresses and maximum-minimum elastic strains are given with detail using contours diagrams and compared with each other to determine the arch thickness effect. At the end of the study, it is seen that the maximum displacements, tensile stresses and strains have a decreasing trend, but compressive stress and strain have an increasing trend by the increasing of arch thickness.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056307
|
oai_dc
|
Optimal layout of a partially treated laminated composite magnetorheological fluid sandwich plate
|
Optimal layout of a partially treated laminated composite magnetorheological fluid sandwich plate
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Vasudevan(VIT University); R. Manoharan(VIT University); A.K. Jeevanantham(VIT University)"
] |
In this study, the optimal location of the MR fluid segments in a partially treated laminated composite sandwich plate has been identified to maximize the natural frequencies and the loss factors. The finite element formulation is used to derive the governing differential equations of motion for a partially treated laminated composite sandwich plate embedded with MR fluid and rubber material as the core layer and laminated composite plate as the face layers. An optimization problem is formulated and solved by combining finite element analysis (FEA) and genetic algorithm (GA) to obtain the optimal locations to yield maximum natural frequency and loss factor corresponding to first five modes of flexural vibration of the sandwich plate with various combinations of weighting factors under various boundary conditions. The proposed methodology is validated by comparing the natural frequencies evaluated at optimal locations of MR fluid pockets identified through GA coupled with FEA and the experimental measurements. The converged results suggest that the optimal location of MR fluid pockets is strongly influenced not only by the boundary conditions and modes of vibrations but also by the objectives of maximization of natural frequency and loss factors either individually or combined. The optimal layout could be useful to apply the MR fluid pockets at critical components of large structure to realize more efficient and compact vibration control mechanism with variable damping.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056317
|
oai_dc
|
Closed-loop structural control with real-time smart sensors
|
Closed-loop structural control with real-time smart sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lauren E. Linderman(University of Minnesota); Billie F. Spencer Jr.(University of Illinois)"
] |
Wireless smart sensors, which have become popular for monitoring applications, are an attractive option for implementing structural control systems, due to their onboard sensing, processing, and communication capabilities. However, wireless smart sensors pose inherent challenges for control, including delays from communication, acquisition hardware, and processing time. Previous research in wireless control, which focused on semi-active systems, has found that sampling rate along with time delays can significantly impact control performance. However, because semi-active systems are guaranteed stable, these issues are typically neglected in the control design. This work achieves active control with smart sensors in an experimental setting. Because active systems are not inherently stable, all the elements of the control loop must be addressed, including data acquisition hardware, processing performance, and control design at slow sampling rates. The sensing hardware is shown to have a significant impact on the control design and performance. Ultimately, the smart sensor active control system achieves comparable performance to the traditional tethered system
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056313
|
oai_dc
|
Active vibration control: considering effect of electric field on coefficients of PZT patches
|
Active vibration control: considering effect of electric field on coefficients of PZT patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sukesha Sharma(Panjab University); Renu Vig(Panjab University); Navin Kumar(IIT Ropar)"
] |
Piezoelectric coefficient and dielectric constant of PZT-5H vary with electric field. In this work, variations of these coefficients with electric field are included in finite element modelling of a cantilevered plate instrumented with piezoelectric patches. Finite element model is reduced using modal truncation and then converted into state-space. First three modal displacements and velocities are estimated using Kalman observer. Negative first modal velocity feedback is used to control the vibrations of the smart plate. Three cases are considered v.i.z case 1: in which variation of piezoelectric coefficient and dielectric constant with electric field is not considered in finite element model and not considered in Kalman observer, case 2: in which variation of piezoelectric coefficient and dielectric constant with electric field is considered in finite element model and not considered in Kalman observer and case 3: in which variation of piezoelectric coefficient and dielectric constant with electric field is considered in finite element model as well as in Kalman observer. Simulation results show that appreciable amount of change would appear if variation of piezoelectric coefficient and dielectric constant with r.m.s. value of electric field is considered.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056316
|
oai_dc
|
Nonlinear control of structure using neuro-predictive algorithm
|
Nonlinear control of structure using neuro-predictive algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Abbas Karamodin(Ferdowsi University); Amir Baghban(Ferdowsi University); Hasan Haji-Kazemi(Ferdowsi University)"
] |
A new neural network (NN) predictive controller (NNPC) algorithm has been developed and tested in the computer simulation of active control of a nonlinear structure. In the present method an NN is used as a predictor. This NN has been trained to predict the future response of the structure to determine the control forces. These control forces are calculated by minimizing the difference between the predicted and desired responses via a numerical minimization algorithm. Since the NNPC is very time consuming and not suitable for real-time control, it is then used to train an NN controller. To consider the effectiveness of the controller on probability of damage, fragility curves are generated. The approach is validated by using simulated response of a 3 story nonlinear benchmark building excited by several historical earthquake records. The simulation results are then compared with a linear quadratic Gaussian (LQG) active controller. The results indicate that the proposed algorithm is completely effective in relative displacement reduction.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056304
|
oai_dc
|
Optimum control system for earthquake-excited building structures with minimal number of actuators and sensors
|
Optimum control system for earthquake-excited building structures with minimal number of actuators and sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jia He(The Hong Kong Polytechnic University); You-Lin Xu(The Hong Kong Polytechnic University); Chao-Dong Zhang(The Hong Kong Polytechnic University); Xiao-Hua Zhang(The Hong Kong Polytechnic University)"
] |
For vibration control of civil structures, especially large civil structures, one of the important issues is how to place a minimal number of actuators and sensors at their respective optimal locations to achieve the predetermined control performance. In this paper, a methodology is presented for the determination of the minimal number and optimal location of actuators and sensors for vibration control of building structures under earthquake excitation. In the proposed methodology, the number and location of the actuators are first determined in terms of the sequence of performance index increments and the predetermined control performance. A multi-scale response reconstruction method is then extended to the controlled building structure for the determination of the minimal number and optimal placement of sensors with the objective that the reconstructed structural responses can be used as feedbacks for the vibration control while the predetermined control performance can be maintained. The feasibility and accuracy of the proposed methodology are finally investigated numerically through a 20-story shear building structure under the El-Centro ground excitation and the Kobe ground excitation. The numerical results show that with the limited number of sensors and actuators at their optimal locations, the predetermined control performance of the building structure can be achieved.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002056306
|
oai_dc
|
Full-scale experimental verification on the vibration control of stay cable using optimally tuned MR damper
|
Full-scale experimental verification on the vibration control of stay cable using optimally tuned MR damper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hongwei Huang(Tongji University); Jiangyun Liu(China Resources Land (Wuhan) Limited); Limin Sun(Tongji University)"
] |
MR dampers have been proposed for the control of cable vibration of cable-stayed bridge in recent years due to their high performance and low energy consumption. However, the highly nonlinear feature of MR dampers makes them difficult to be designed with efficient semi-active control algorithms. Simulation study has previously been carried out on the cable-MR damper system using a semi-active control algorithm derived based on the universal design curve of dampers and a bilinear mechanical model of the MR damper. This paper aims to verify the effectiveness of the MR damper for mitigating cable vibration through a full-scale experimental test, using the same semi-active control strategy as in the simulation study. A long stay cable fabricated for a real bridge was set-up with the MR damper installed. The cable was excited under both free and forced vibrations. Different test scenarios were considered where the MR damper was tuned as passive damper with minimum or maximum input current, or the input current of the damper was changed according to the proposed semi-active control algorithm. The effectiveness of the MR damper for controlling the cable vibration was assessed through computing the damping ratio of the cable for free vibration and the root mean square value of acceleration of the cable for forced vibration.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079448
|
oai_dc
|
A two-stage damage detection method for truss structures using a modal residual vector based indicator and differential evolution algorithm
|
A two-stage damage detection method for truss structures using a modal residual vector based indicator and differential evolution algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Seyed Mohammad Seyedpoor(Shomal University); Maryam Montazer(Shomal University)"
] |
A two-stage method for damage detection in truss systems is proposed. In the first stage, a modal residual vector based indicator (MRVBI) is introduced to locate the potentially damaged elements and reduce the damage variables of a truss structure. Then, in the second stage, a differential evolution (DE) based optimization method is implemented to find the actual site and extent of damage in the structure. In order to assess the efficiency of the proposed damage detection method, two numerical examples including a 2D-truss and 3D-truss are considered. Simulation results reveal the high performance of the method for accurately identifying the damage location and severity of trusses with considering the measurement noise.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079417
|
oai_dc
|
An approach to design and fabrication of resonant giant magnetostrictive transducer
|
An approach to design and fabrication of resonant giant magnetostrictive transducer
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad R. Sheykholeslami(Arak University); Yousef Hojjat(Tarbiat Modares University); M. Karafi(Tarbiat Modares University); Simone Cinquemani(Politecnico di Milano); Mojtaba Ghodsi(Sultan Qaboos University)"
] |
The paper provides a comprehensive procedure for the mechanical and magnetic design of Langevin transducer based on giant magnetostrictive material. The the transducer is designed to work at its second mode of vibration, having high mechanical quality factor and low damping coefficient. The design procedure is based on an analytical model and it is verified by finite-element analysis. Experimental tests based on impedance response analysis in first and second modes are carried out on the prototype. Results confirm the appropriate design of this transducer, demonstrating the highest mechanical quality factor between the resonant transducers in the literature.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079447
|
oai_dc
|
SH-wave in a piezomagnetic layer overlying an initially stressed orthotropic half-space
|
SH-wave in a piezomagnetic layer overlying an initially stressed orthotropic half-space
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rajneesh Kakar(Chotti Baradari, 163/1, Jalandhar-144022); Shikha Kakar(SBBSIET)"
] |
The existence of SH-wave in a piezomagnetic layer overlying an initially stressed orthotropic half-space is investigated. The coupled of differential equations are solved for piezomagnetic layer overlying an orthotropic elastic half-space. The general dispersion equation has been derived for both magnetically open circuit and magnetically closed circuits under the four types of boundary conditions. In the absence of the piezomagnetic properties, initial stress and orthotropic properties of the medium, the dispersion equations reduce to classical Love equation. The SH-wave velocity has been calculated numerically for both magnetically open circuit and closed circuits. The effect of initial stress and magnetic permeability are illustrated by graphs in both the cases. The velocity of SH-wave decreases with the increment of wave number.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079414
|
oai_dc
|
On bending, buckling and vibration of graphene nanosheets based on the nonlocal theory
|
On bending, buckling and vibration of graphene nanosheets based on the nonlocal theory
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jinjian Liu(Soochow University); Ling Chen(Soochow University); Feng Xie(Soochow University); Xueliang Fan (Soochow University); Cheng Li(Soochow University)"
] |
The nonlocal static bending, buckling, free and forced vibrations of graphene nanosheets are examined based on the Kirchhoff plate theory and Taylor expansion approach. The nonlocal nanoplate model incorporates the length scale parameter which can capture the small scale effect. The governing equations are derived using Hamilton\'s principle and the Navier-type solution is developed for simply-supported graphene nanosheets. The analytical results are proposed for deflection, natural frequency, amplitude of forced vibration and buckling load. Moreover, the effects of nonlocal parameter, half wave number and three-dimensional sizes on the static, dynamic and stability responses of the graphene nanosheets are discussed. Some illustrative examples are also addressed to verify the present model, methodology and solution. The results show that the new nanoplate model produces larger deflection, smaller circular frequencies, amplitude and buckling load compared with the classical model.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079413
|
oai_dc
|
Closed-form optimum tuning formulas for passive Tuned Mass Dampers under benchmark excitations
|
Closed-form optimum tuning formulas for passive Tuned Mass Dampers under benchmark excitations
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jonathan Salvi(Universita di Bergamo); Egidio Rizzi(Universita di Bergamo)"
] |
This study concerns the derivation of optimum tuning formulas for a passive Tuned Mass Damper (TMD) device, for the case of benchmark ideal excitations acting on a single-degree-of-freedom (SDOF) damped primary structure. The free TMD parameters are tuned first through a non-linear gradient-based optimisation algorithm, for the case of harmonic or white noise excitations, acting either as force on the SDOF primary structure or as base acceleration. The achieved optimum TMD parameters are successively interpolated according to appropriate analytical fitting proposals, by non-linear least squares, in order to produce simple and effective TMD tuning formulas. In particular, two fitting models are presented. The main proposal is composed of a simple polynomial relationship, refined within the fitting process, and constitutes the optimum choice. A second model refers to proper modifications of literature formulas for the case of an undamped primary structure. The results in terms of final (interpolated) optimum TMD parameters and of device effectiveness in reducing the structural dynamic response are finally displayed and discussed in detail, showing the wide and ready-to-use validity of the proposed optimisation procedure and achieved tuning formulas. Several post-tuning trials have been carried out as well on SDOF and MDOF shear-type frame buildings, by confirming the effective benefit provided by the proposed optimum TMD.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079410
|
oai_dc
|
Synergetics based damage detection of frame structures using piezoceramic patches
|
Synergetics based damage detection of frame structures using piezoceramic patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiaobin Hong(South China University of Technology); Jiaobiao Ruan(University of Houston); Guixiong Liu(South China University of Technology); Tao Wang(University of Houston); Youyong Li(Wuhan University of Science and Technology); Gangbing Song(University of Houston)"
] |
This paper investigates the Synergetics based Damage Detection Method (SDDM) for frame structures by using surface-bonded PZT (Lead Zirconate Titanate) patches. After analyzing the mechanism of pattern recognition from Synergetics, the operating framework with cooperation-competition-update process of SDDM was proposed. First, the dynamic identification equation of structural conditions was established and the adjoint vector (AV) set of original vector (OV) set was obtained by Generalized Inverse Matrix (GIM).Then, the order parameter equation and its evolution process were deduced through the strict mathematics ratiocination. Moreover, in order to complete online structural condition update feature, the iterative update algorithm was presented. Subsequently, the pathway in which SDDM was realized through the modified Synergetic Neural Network (SNN) was introduced and its assessment indices were confirmed. Finally, the experimental platform with a two-story frame structure was set up. The performances of the proposed methodology were tested for damage identifications by loosening various screw nuts group scenarios. The experiments were conducted in different damage degrees, the disturbance environment and the noisy environment, respectively. The results show the feasibility of SDDM using piezoceramic sensors and actuators, and demonstrate a strong ability of anti-disturbance and anti-noise in frame structure applications. This proposed approach can be extended to the similar structures for damage identification.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079416
|
oai_dc
|
Performance evaluation of soil-embedded plastic optical fiber sensors for geotechnical monitoring
|
Performance evaluation of soil-embedded plastic optical fiber sensors for geotechnical monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cheng-Cheng Zhang(Nanjing University); Hong-Hu Zhu(Nanjing University); Bin Shi(Nanjing University); Jun-Kuan She(Nanjing University); Dan Zhang(Nanjing University)"
] |
Based on the distributed fiber optic sensing (DFOS) technique, plastic optical fibers (POFs) are attractive candidates to measure deformations of geotechnical structures because they can withstand large strains before rupture. Understanding the mechanical interaction between an embedded POF and the surrounding soil or rock is a necessary step towards establishing an effective POF-based sensing system for geotechnical monitoring. This paper describes a first attempt to evaluate the feasibility of POF-based soil deformation monitoring considering the POF–soil interfacial properties. A series of pullout tests were performed under various confining pressures (CPs) on a jacketed polymethyl methacrylate (PMMA) POF embedded in soil specimens. The test results were interpreted using a fiber–soil interaction model, and were compared with previous test data of silica optical fibers (SOFs). The results showed that the range of CP in this study did not induce plastic deformation of the POF; therefore, the POF–soil and the SOF–soil interfaces had similar behavior. CP was found to play an important role in controlling the fiber–soil interfacial bond and the fiber measurement range. Moreover, an expression was formulated to determine whether a POF would undergo plastic deformation when measuring soil deformation. The plasticity of POF may influence the reliability of measurements, especially for monitored geo-structures whose deformation would alternately increase and decrease. Taken together, these results indicate that in terms of the interfacial parameters studied here the POF is feasible for monitoring soil deformation as long as the plastic deformation issue is carefully addressed.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079411
|
oai_dc
|
Vibration control of hysteretic base-isolated structures: an LMI approach
|
Vibration control of hysteretic base-isolated structures: an LMI approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Francesc Pozo(Universitat Politècnica de Catalunya (UPC)); Gisela Pujol(Universitat Politècnica de Catalunya (UPC)); Leonardo Acho(Universitat Politècnica de Catalunya (UPC))"
] |
Seismic isolation systems are essentially designed to preserve structural safety, prevent occupants injury and properties damage. An active saturated LMI-based control design is proposed to attenuate seismic disturbances in base-isolated structures under saturation actuators. Using a mathematical model of an eight-storied building structure, an active control algorithm is designed. Performance evaluation of the controller is carried out in a simplified model version of a benchmark building system, which is recognized as a state-of-the-art model for numerical experiments of structures under seismic perturbations. Experimental results show that the proposed algorithm is robust with respect to model and seismic perturbations. Finally, the performance indices show that the proposed controller behaves satisfactorily and with a reasonable control effort.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079412
|
oai_dc
|
Operational modal analysis of Canton Tower by a fast frequency domain Bayesian method
|
Operational modal analysis of Canton Tower by a fast frequency domain Bayesian method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Feng-Liang Zhang(Tongji University); Yan-Chun Ni(Tongji University); Yan-Chun Ni(The Hong Kong Polytechnic University); You-Wu Wang(The Hong Kong Polytechnic University)"
] |
The Canton Tower is a high-rise slender structure with a height of 610 m. A structural health monitoring system has been instrumented on the structure, by which data is continuously monitored. This paper presents an investigation on the identified modal properties of the Canton Tower using ambient vibration data collected during a whole day (24 hours). A recently developed Fast Bayesian FFT method is utilized for operational modal analysis on the basis of the measured acceleration data. The approach views modal identification as an inference problem where probability is used as a measure for the relative plausibility of outcomes given a model of the structure and measured data. Focusing on the first several modes, the modal properties of this supertall slender structure are identified on non-overlapping time windows during the whole day under normal wind speed. With the identified modal parameters and the associated posterior uncertainty, the distribution of the modal parameters in the future is predicted and assessed. By defining the modal root-mean-square value in terms of the power spectral density of modal force identified, the identified natural frequencies and damping ratios versus the vibration amplitude are investigated with the associated posterior uncertainty considered. Meanwhile, the correlations between modal parameters and temperature, modal parameters and wind speed are studied. For comparison purpose, the frequency domain decomposition (FDD) method is also utilized to identify the modal parameters. The identified results obtained by the Bayesian method, the FDD method and a finite element model are compared and discussed.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002079415
|
oai_dc
|
A new configuration in a prosthetic knee using of hybrid concept of an MR brake with a T-shaped drum incorporating an arc form surface
|
A new configuration in a prosthetic knee using of hybrid concept of an MR brake with a T-shaped drum incorporating an arc form surface
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hassan Sayyaadi(Sharif University of Technology); Seiyed Hamid Zareh(Sharif University of Technology)"
] |
This paper focuses on developing a new configuration on magnetorheological (MR) brake damper as prosthetic knee. Prosthetic knee uses magnetic fields to vary the viscosity of the MR fluid, and thereby its flexion resistance. Exerted transmissibility torque of the knee greatly depends on the magnetic field intensity in the MR fluid. In this study a rotary damper using MR fluid is addressed in which a single rotary disc will act as a brake while MR fluid is activated by magnetic field in different walking gait. The main objective of this study is to investigate a prosthetic knee with one activating rotary disc to accomplish necessary braking torque in walking gait via T-shaped drum with arc surface boundary and implementing of Newton\'s equation of motion to derive generated torque at the inner surface of the rotary drum. For this purpose a novel configuration of a T-shaped drum based on the effects of a material deformation process is proposed. In this new design, the T-shaped disc will increase the effective areas of influences in between drum and MR fluid together and the arc wall crushes the particles chains (fibrils) of the MR fluid together instead of breaking them via strain in a conventional MR brake. To verify the proposed MR brake, results of the proposed and conventional MR brakes are compared together and demonstrated that the resisting torque of the proposed MR brake is almost two times greater than that of the conventional brake.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114738
|
oai_dc
|
Statistical analysis and probabilistic modeling of WIM monitoring data of an instrumented arch bridge
|
Statistical analysis and probabilistic modeling of WIM monitoring data of an instrumented arch bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.W. Ye(Zhejiang University); Y.H. Su(Zhejiang University); P.S. Xi(Zhejiang University); B. Chen(Zhejiang University); J.P. Han(Lanzhou University of Technology)"
] |
Traffic load and volume is one of the most important physical quantities for bridge safety evaluation and maintenance strategies formulation. This paper aims to conduct the statistical analysis of traffic volume information and the multimodal modeling of gross vehicle weight (GVW) based on the monitoring data obtained from the weigh-in-motion (WIM) system instrumented on the arch Jiubao Bridge located in Hangzhou, China. A genetic algorithm (GA)-based mixture parameter estimation approach is developed for derivation of the unknown mixture parameters in mixed distribution models. The statistical analysis of one-year WIM data is firstly performed according to the vehicle type, single axle weight, and GVW. The probability density function (PDF) and cumulative distribution function (CDF) of the GVW data of selected vehicle types are then formulated by use of three kinds of finite mixed distributions (normal, lognormal and Weibull). The mixture parameters are determined by use of the proposed GA-based method. The results indicate that the stochastic properties of the GVW data acquired from the field-instrumented WIM sensors are effectively characterized by the method of finite mixture distributions in conjunction with the proposed GA-based mixture parameter identification algorithm. Moreover, it is revealed that the Weibull mixture distribution is relatively superior in modeling of the WIM data on the basis of the calculated Akaike
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114733
|
oai_dc
|
Operational modal analysis of reinforced concrete bridges using autoregressive model
|
Operational modal analysis of reinforced concrete bridges using autoregressive model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kyeongtaek Park(Ulsan National Institute of Science and Technology); Sehwan Kim(Dankook University); Marco Torbol(Ulsan National Institute of Science and Technology)"
] |
This study focuses on the system identification of reinforced concrete bridges using vector autoregressive model (VAR). First, the time series output response from a bridge establishes the autoregressive (AR) models. AR models are one of the most accurate methods for stationary time series. Burg\'s algorithm estimates the autoregressive coefficients (ARCs) at p-lag by reducing the sum of the forward and the backward errors. The computed ARCs are assembled in the state system matrix and the eigen-system realization algorithm (ERA) computes: the eigenvector matrix that contains the vectors of the mode shapes, and the eigenvalue matrix that contains the associated natural frequencies. By taking advantage of the characteristic of the AR model with ERA (ARMERA), civil engineering can address problems related to damage detection. Operational modal analysis using ARMERA is applied to three experiments. One experiment is coupled with an artificial neural network algorithm and it can detect damage locations and extension. The neural network uses a specific number of ARCs as input and multiple submatrix scaling factors of the structural stiffness matrix as output to represent the damage.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114734
|
oai_dc
|
Canonical correlation analysis based fault diagnosis method for structural monitoring sensor networks
|
Canonical correlation analysis based fault diagnosis method for structural monitoring sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hai-Bin Huang(Dalian University of Technology); Ting-Hua Yi (Dalian University of Technology); Hong-Nan Li(Shenyang Jianzhu University)"
] |
The health conditions of in-service civil infrastructures can be evaluated by employing structural health monitoring technology. A reliable health evaluation result depends heavily on the quality of the data collected from the structural monitoring sensor network. Hence, the problem of sensor fault diagnosis has gained considerable attention in recent years. In this paper, an innovative sensor fault diagnosis method that focuses on fault detection and isolation stages has been proposed. The dynamic or auto-regressive characteristic is firstly utilized to build a multivariable statistical model that measures the correlations of the currently collected structural responses and the future possible ones in combination with the canonical correlation analysis. Two different fault detection statistics are then defined based on the above multivariable statistical model for deciding whether a fault or failure occurred in the sensor network. After that, two corresponding fault isolation indices are deduced through the contribution analysis methodology to identify the faulty sensor. Case studies, using a benchmark structure developed for bridge health monitoring, are considered in the research and demonstrate the superiority of the new proposed sensor fault diagnosis method over the traditional principal component analysis-based and the dynamic principal component analysis-based methods.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114736
|
oai_dc
|
An anisotropic ultrasonic transducer for Lamb wave applications
|
An anisotropic ultrasonic transducer for Lamb wave applications
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wensong Zhou(Harbin Institute of Technology); Hui Li (Harbin Institute of Technology); Fuh-Gwo Yuan(North Carolina State University)"
] |
An anisotropic ultrasonic transducer is proposed for Lamb wave applications, such as passive damage or impact localization based on ultrasonic guided wave theory. This transducer is made from a PMNPT single crystal, and has different piezoelectric coefficients d31 and d32, which are the same for the conventional piezoelectric materials, such as Lead zirconate titanate (PZT). Different piezoelectric coefficients result in directionality of guided wave generated by this transducer, in other words, it is an anisotropic ultrasonic transducer. And thus, it has different sensitivity in comparison with conventional ultrasonic transducer. The anisotropic one can provide more information related to the direction when it is used as sensors. This paper first shows its detailed properties, including analytical formulae and finite elements simulations. Then, its application is described.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114730
|
oai_dc
|
A hybrid self-adaptive Firefly-Nelder-Mead algorithm for structural damage detection
|
A hybrid self-adaptive Firefly-Nelder-Mead algorithm for structural damage detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chu-Dong Pan(Jinan University); Ling Yu(Jinan University); Ze-Peng Chen(Jinan University); Wen-Feng Luo(Jinan University); Huan-Lin Liu(Jinan University)"
] |
Structural damage detection (SDD) is a challenging task in the flied of structural health monitoring (SHM). As an exploring attempt to the SDD problem, a hybrid self-adaptive Firefly-Nelder-Mead (SA-FNM) algorithm is proposed for the SDD problem in this study. First of all, the basic principle of firefly algorithm (FA) is introduced. The Nelder-Mead (NM) algorithm is incorporated into FA for improving the local searching ability. A new strategy for exchanging the information in the firefly group is introduced into SA-FNM for reducing the computation cost. A random walk strategy for the best firefly and a self-adaptive control strategy of three key parameters,such as light absorption, randomization parameter and critical distance, are proposed for preferably balancing the exploitation and exploration ability of the SA-FNM. The computing performance of the SA-FNM is evaluated and compared with the basic FA by three benchmark functions. Secondly, the SDD problem is mathematically converted into a constrained optimization problem, which is then hopefully solved by the SA-FNM algorithm. A multi-step method is proposed for finding the minimum fitness with a big probability. In order to assess the accuracy and the feasibility of the proposed method, a two-storey rigid frame structure without considering the finite element model (FEM) error and a steel beam with considering the model error are taken examples for numerical simulations. Finally, a series of experimental studies on damage detection of a steel beam with four damage patterns are performed in laboratory. The illustrated results show that the proposed method can accurately identify the structural damage. Some valuable conclusions are made and related issues are discussed as well.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114724
|
oai_dc
|
Compensation of temperature effect on impedance responses of PZT interface for prestress-loss monitoring in PSC girders
|
Compensation of temperature effect on impedance responses of PZT interface for prestress-loss monitoring in PSC girders
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Thanh-Canh Huynh(Pukyong National University); Jeong-Tae Kim(Pukyong National University)"
] |
In this study, a method to compensate the effect of temperature variation on impedance responses which are used for prestress-loss monitoring in prestressed concrete (PSC) girders is presented. Firstly, an impedance-based technique using a mountable lead-zirconate-titanate (PZT) interface is presented for prestress-loss monitoring in the local tendon-anchorage member. Secondly, a cross-correlation-based algorithm to compensate the effect of temperature variation in the impedance signatures is outlined. Thirdly, lab-scale experiments are performed on a PSC girder instrumented with a mountable PZT interface at the tendon-anchorage. A series of temperature variation and prestress-loss events are simulated for the lab-scale PSC girder. Finally, the feasibility of the proposed method is experimentally verified for prestress-loss monitoring in the PSC girder under temperature-varying conditions and prestress-loss events.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114726
|
oai_dc
|
Improved Kalman filter with unknown inputs based on data fusion of partial acceleration and displacement measurements
|
Improved Kalman filter with unknown inputs based on data fusion of partial acceleration and displacement measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lijun Liu(Xiamen University); Jiajia Zhu(Xiamen University); Ying Su(Xiamen University); Ying Lei(Xiamen University)"
] |
The classical Kalman filter (KF) provides a practical and efficient state estimation approach for structural identification and vibration control. However, the classical KF approach is applicable only when external inputs are assumed known. Over the years, some approaches based on Kalman filter with unknown inputs (KF-UI) have been presented. However, these approaches based solely on acceleration measurements are inherently unstable which leads poor tracking and so-called drifts in the estimated unknown inputs and structural displacement in the presence of measurement noises. Either on-line regularization schemes or post signal processing is required to treat the drifts in the identification results, which prohibits the real-time identification of joint structural state and unknown inputs. In this paper, it is aimed to extend the classical KF approach to circumvent the above limitation for real time joint estimation of structural states and the unknown inputs. Based on the scheme of the classical KF, analytical recursive solutions of an improved Kalman filter with unknown excitations (KF-UI) are derived and presented. Moreover, data fusion of partially measured displacement and acceleration responses is used to prevent in real time the so-called drifts in the estimated structural state vector and unknown external inputs. The effectiveness and performance of the proposed approach are demonstrated by some numerical examples.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114732
|
oai_dc
|
Extrapolation of extreme traffic load effects on bridges based on long-term SHM data
|
Extrapolation of extreme traffic load effects on bridges based on long-term SHM data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.X. Xia(The Hong Kong Polytechnic University); Y.Q. Ni(The Hong Kong Polytechnic University)"
] |
In the design and condition assessment of bridges, it is usually necessary to take into consideration the extreme conditions which are not expected to occur within a short time period and thus require an extrapolation from observations of limited duration. Long-term structural health monitoring (SHM) provides a rich database to evaluate the extreme conditions. This paper focuses on the extrapolation of extreme traffic load effects on bridges using long-term monitoring data of structural strain. The suspension Tsing Ma Bridge (TMB), which carries both highway and railway traffic and is instrumented with a long-term SHM system, is taken as a testbed for the present study. Two popular extreme value extrapolation methods: the block maxima approach and the peaks-over-threshold approach, are employed to extrapolate the extreme stresses induced by highway traffic and railway traffic, respectively. Characteristic values of the extreme stresses with a return period of 120 years (the design life of the bridge) obtained by the two methods are compared. It is found that the extrapolated extreme stresses are robust to the extrapolation technique. It may owe to the richness and good quality of the long-term strain data acquired. These characteristic extremes are also compared with the design values and found to be much smaller than the design values, indicating conservative design values of traffic loading and a safe traffic-loading condition of the bridge. The results of this study can be used as a reference for the design and condition assessment of similar bridges carrying heavy traffic, analogous to the TMB.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114727
|
oai_dc
|
Synergic identification of prestress force and moving load on prestressed concrete beam based on virtual distortion method
|
Synergic identification of prestress force and moving load on prestressed concrete beam based on virtual distortion method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ziru Xiang(Queensland University of Technology (QUT)); Tommy H.T. Chan(Queensland University of Technology (QUT)); David P. Thambiratnam(Queensland University of Technology (QUT)); Theanh Nguyen(Queensland University of Technology (QUT))"
] |
In a prestressed concrete bridge, the magnitude of the prestress force (PF) decreases with time. This unexpected loss can cause failure of a bridge which makes prestress force identification (PFI) critical to evaluate bridge safety. However, it has been difficult to identify the PF non-destructively. Although some research has shown the feasibility of vibration based methods in PFI, the requirement of having a determinate exciting force in these methods hinders applications onto in-service bridges. Ideally, it will be efficient if the normal traffic could be treated as an excitation, but the load caused by vehicles is difficult to measure. Hence it prompts the need to investigate whether PF and moving load could be identified together. This paper presents a synergic identification method to determine PF and moving load applied on a simply supported prestressed concrete beam via the dynamic responses caused by this unknown moving load. This method consists of three parts: (i) the PF is transformed into an external pseudo-load localized in each beam element via virtual distortion method (VDM); (ii) then these pseudo-loads are identified simultaneously with the moving load via Duhamel Integral; (iii) the time consuming problem during the inversion of Duhamel Integral is overcome by the load-shape function (LSF). The method is examined against different cases of PFs, vehicle speeds and noise levels by means of simulations. Results show that this method attains a good degree of accuracy and efficiency, as well as robustness to noise.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114728
|
oai_dc
|
Image-based structural dynamic displacement measurement using different multi-object tracking algorithms
|
Image-based structural dynamic displacement measurement using different multi-object tracking algorithms
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.W. Ye(Zhejiang University); C.Z. Dong(Zhejiang University); T. Liu(Zhejiang University)"
] |
With the help of advanced image acquisition and processing technology, the vision-based measurement methods have been broadly applied to implement the structural monitoring and condition identification of civil engineering structures. Many noncontact approaches enabled by different digital image processing algorithms are developed to overcome the problems in conventional structural dynamic displacement measurement. This paper presents three kinds of image processing algorithms for structural dynamic displacement measurement, i.e., the grayscale pattern matching (GPM) algorithm, the color pattern matching (CPM) algorithm, and the mean shift tracking (MST) algorithm. A vision-based system programmed with the three image processing algorithms is developed for multi-point structural dynamic displacement measurement. The dynamic displacement time histories of multiple vision points are simultaneously measured by the vision-based system and the magnetostrictive displacement sensor (MDS) during the laboratory shaking table tests of a three-story steel frame model. The comparative analysis results indicate that the developed vision-based system exhibits excellent performance in structural dynamic displacement measurement by use of the three different image processing algorithms. The field application experiments are also carried out on an arch bridge for the measurement of displacement influence lines during the loading tests to validate the effectiveness of the vision-based system.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114737
|
oai_dc
|
Stationary and nonstationary analysis on the wind characteristics of a tropical storm
|
Stationary and nonstationary analysis on the wind characteristics of a tropical storm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tianyou Tao(Southeast University); Hao Wang(Southeast University); Aiqun Li(Southeast University)"
] |
Nonstationary features existing in tropical storms have been frequently captured in recent field measurements, and the applicability of the stationary theory to the analysis of wind characteristics needs to be discussed. In this study, a tropical storm called Nakri measured at Taizhou Bridge site based on structural health monitoring (SHM) system in 2014 is analyzed to give a comparison of the stationary and nonstationary characteristics. The stationarity of the wind records in the view of mean and variance is first evaluated with the run test method. Then the wind data are respectively analyzed with the traditional stationary model and the wavelet-based nonstationary model. The obtained wind characteristics such as the mean wind velocity, turbulence intensity, turbulence integral scale and power spectral density (PSD) are compared accordingly. Also, the stationary and nonstationary PSDs are fitted to present the turbulence energy distribution in frequency domain, among which a modulating function is included in the nonstationary PSD to revise the non-monotonicity. The modulated nonstationary PSD can be utilized to unconditionally simulate the turbulence presented by the nonstationary wind model. The results of this study recommend a transition from stationarity to nonstationarity in the analysis of wind characteristics, and further in the accurate prediction of wind-induced vibrations for engineering structures.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114723
|
oai_dc
|
Damage detection of a cable-stayed bridge based on the variation of stay cable forces eliminating environmental temperature effects
|
Damage detection of a cable-stayed bridge based on the variation of stay cable forces eliminating environmental temperature effects
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chien-Chou Chen(National Yunlin University of Science and Technology); Wen-Hwa Wu(National Yunlin University of Science and Technology); Chun-Yan Liu(National Yunlin University of Science and Technology); Gwolong Lai(National Yunlin University of Science and Technology)"
] |
This study aims to establish an effective methodology for the detection of instant damages occurred in cable-stayed bridges with the measurements of cable vibration and structural temperatures. A transfer coefficient for the daily temperature variation and another for the long-term temperature variation are firstly determined to eliminate the environmental temperature effects from the cable force variation. Several thresholds corresponding to different levels of exceedance probability are then obtained to decide four upper criteria and four lower criteria for damage detection. With these criteria, the monitoring data for three stay cables of Ai-Lan Bridge are analyzed and compared to verify the proposed damage detection methodology. The simulated results to consider various damage scenarios unambiguously indicate that the damages with cable force changes larger than +-1.5% can be detected within 12 hours. Even though not exhaustively reflecting the environmental temperature effects on the cable force variation, both the effective temperature and the air temperature can be considered as valid indices to eliminate these effects at high and low monitoring costs.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114739
|
oai_dc
|
Field monitoring of the train-induced hanger vibration in a high-speed railway steel arch bridge
|
Field monitoring of the train-induced hanger vibration in a high-speed railway steel arch bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Youliang Ding(Southeast University); Yonghui An (Dalian University of Technology); Chao Wang(Southeast University)"
] |
Studies on dynamic characteristics of the hanger vibration using field monitoring data are important for the design and evaluation of high-speed railway truss arch bridges. This paper presents an analysis of the hanger\'s dynamic displacement responses based on field monitoring of Dashengguan Yangtze River Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The three vibration parameters, i.e., dynamic displacement amplitude, dynamic load factor and vibration amplitude, are selected to investigate the hanger\'s vibration characteristics in each railway load case including the probability statistical characteristics and coupled vibration characteristics. The influences of carriageway and carriage number on the hanger\'s vibration characteristics are further investigated. The results indicate that: (1) All the eight railway load cases can be successfully identified according to the relationship of responses from strain sensors and accelerometers in the structural health monitoring system. (2) The hanger\'s three vibration parameters in each load case in the longitudinal and transverse directions have obvious probabilistic characteristics. However, they fall into different distribution functions. (3) There is good correlation between the hanger\'s longitudinal/transverse dynamic displacement and the main girder\'s transverse dynamic displacement in each load case, and their relationships are shown in the hysteresis curves. (4) Influences of the carriageway and carriage number on the hanger\'s three parameters are different in both longitudinal and transverse directions; while the influence on any of the three parameters presents an obvious statistical trend. The present paper lays a good foundation for the further analysis of train-induced hanger vibration and control.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002114731
|
oai_dc
|
Performance indicator of the atmospheric corrosion monitor and concrete corrosion sensors in Kuwait field research station
|
Performance indicator of the atmospheric corrosion monitor and concrete corrosion sensors in Kuwait field research station
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Husain(Kuwait Institute for Scientific Research); Suad Kh. Al-Bahar(Kuwait Institute for Scientific Research); Safaa A. Abdul Salam(Kuwait Institute for Scientific Research)"
] |
Two field research stations based upon atmospheric corrosivity monitoring combined with reinforced concrete corrosion rate sensors have been established in Kuwait. This was established for the purpose of remote monitoring of building materials performance for concrete under Kuwait atmospheric environment. The two field research sites for concrete have been based upon an outcome from a research investigation intended for monitoring the atmospheric corrosivity from weathering station distributed in eight areas, and in different regions in Kuwait. Data on corrosivity measurements are essential for the development of specification of an optimized corrosion resistance system for reinforced concrete manufactured products. This study aims to optimize, characterize, and utilize long-term concrete structural health monitoring through on line corrosion measurement and to determine the feasibility and viability of the integrated anode ladder corrosion sensors embedded in concrete. The atmospheric corrosivity categories supported with GSM remote data acquisition system from eight corrosion monitoring stations at different regions in Kuwait are being classified according to standard ISO 9223. The two nominated field sites where based upon time of wetness and bimetallic corrosion rate from atmospheric data where metals and rebar\'s concrete are likely to be used. Eight concrete blocks with embeddable anodic ladder corrosion sensors were placed in the atmospheric zone adjacent to the sea shore at KISR site. The anodic ladder corrosion rate sensors for concrete were installed to provide an early warning system on prediction of the corrosion propagation and on developing new insights on the long‐term durability performance and repair of concrete structures to lower labor cost. The results show the atmospheric corrosivity data of the environment and the feasibility of data retrieval of the corrosion potential of concrete from the embeddable sets of anodic ladder corrosion sensors.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040929
|
oai_dc
|
Building structural health monitoring using dense and sparse topology wireless sensor network
|
Building structural health monitoring using dense and sparse topology wireless sensor network
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad E. Haque(Universiti Kebangsaan Malaysia (UKM)); Mohammad F.M. Zain(Universiti Kebangsaan Malaysia (UKM)); Mohammad A. Hannan(Universiti Kebangsaan Malaysia (UKM)); Mohammad H. Rahman(UNSW at the Australian Defense Force Academy)"
] |
Wireless sensor technology has been opened up numerous opportunities to advanced health and maintenance monitoring of civil infrastructure. Compare to the traditional tactics, it offers a better way of providing relevant information regarding the condition of building structure health at a lower price. Numerous domestic buildings, especially longer-span buildings have a low frequency response and challenging to measure using deployed numbers of sensors. The way the sensor nodes are connected plays an important role in providing the signals with required strengths. Out of many topologies, the dense and sparse topologies wireless sensor network were extensively used in sensor network applications for collecting health information. However, it is still unclear which topology is better for obtaining health information in terms of greatest components, node\'s size and degree. Theoretical and computational issues arising in the selection of the optimum topology sensor network for estimating coverage area with sensor placement in building structural monitoring are addressed. This work is an attempt to fill this gap in high-rise building structural health monitoring application. The result shows that, the sparse topology sensor network provides better performance compared with the dense topology network and would be a good choice for monitoring high-rise building structural health damage.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040942
|
oai_dc
|
Life cycle cost analysis and smart operation mode of ground source heat pump system
|
Life cycle cost analysis and smart operation mode of ground source heat pump system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"윤석(한국원자력연구원); 이승래(Korean Advanced Institute for Science and Technology)"
] |
This paper presents an advanced life cycle cost (LCC) analysis of a ground source heat pump (GSHP) system and suggests a smart operation mode with a thermal performance test (TPT) and an energy pile system constructed on the site of the Incheon International Airport (IIA). First, an economic analysis of the GSHP system was conducted for the second passenger terminal of the IIA considering actual influencing factors such as government support and the residual value of the equipment. The analysis results showed that the economic efficiency of the GSHP system could be increased owing to several influential factors. Second, a multiple regression analysis was conducted using different independent variables in order to analyze the influence indices with regard to the LCC results. Every independent index, in this case the initial construction cost, lifespan of the equipment, discount rate and the amount of price inflation can affect the LCC results. Third, a GSHP system using an energy pile was installed on the site of the construction laboratory institute of the IIA. TPTs of W-shape and spiral-coil-type GHEs were conducted in continuous and intermittent operation modes, respectively, prior to system operation of the energy pile. A cooling GSHP system in the energy pile was operated in both the continuous and intermittent modes, and the LCC was calculated. Furthermore, the smart operation mode and LCC were analyzed considering the application of a thermal storage tank.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040931
|
oai_dc
|
Modelling and experimental investigations on stepped beam with cavity for energy harvesting
|
Modelling and experimental investigations on stepped beam with cavity for energy harvesting
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Rami Reddy(National Institute of Technology); M. Umapathy(National Institute of Technology); D. Ezhilarasi(National Institute of Technology); G. Uma(National Institute of Technology)"
] |
This paper presents techniques to harvest higher voltage from piezoelectric cantilever energy harvester by structural alteration. Three different energy harvesting structures are considered namely, stepped cantilever beam, stepped cantilever beam with rectangular and trapezoidal cavity. The analytical model of three energy harvesting structures are developed using Euler-Bernoulli beam theory. The thickness, position of the rectangular cavity and the taper angle of the trapezoidal cavity is found to shift the neutral axis away from the surface of the piezoelectric element which in turn increases the generated voltage. The performance of the energy harvesters is evaluated experimentally and is compared with regular piezoelectric cantilever energy harvester. The analytical and experimental investigations reveal that, the proposed energy harvesting structures generate higher output voltage as compared to the regular piezoelectric cantilever energy harvesting structure. This work suggests that through simple structural modifications higher energy can be harvested from the widely reported piezoelectric cantilever energy harvester.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040933
|
oai_dc
|
A simple and efficient 1-D macroscopic model for shape memory alloys considering ferro-elasticity effect
|
A simple and efficient 1-D macroscopic model for shape memory alloys considering ferro-elasticity effect
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.R. Damanpack(The Chinese University of Hong Kong); M. Bodaghi(The Chinese University of Hong Kong); W.H. Liao(The Chinese University of Hong Kong); M.M. Aghdam(Amirkabir University of Technology); M. Shakeri(Amirkabir University of Technology)"
] |
In this paper, a simple and efficient phenomenological macroscopic one-dimensional model is proposed which is able to simulate main features of shape memory alloys (SMAs) particularly ferro-elasticity effect. The constitutive model is developed within the framework of thermodynamics of irreversible processes to simulate the one-dimensional behavior of SMAs under uniaxial simple tension-compression as well as pure torsion+/- loadings. Various functions including linear, cosine and exponential functions are introduced in a unified framework for the martensite transformation kinetics and an analytical description of constitutive equations is presented. The presented model can be used to reproduce primary aspects of SMAs including transformation/orientation of martensite phase, shape memory effect, pseudo-elasticity and in particular ferro-elasticity. Experimental results available in the open literature for uniaxial tension, torsion and bending tests are simulated to validate the present SMA model in capturing the main mechanical characteristics. Due to simplicity and accuracy, it is expected the present SMA model will be instrumental toward an accurate analysis of SMA components in various engineering structures particularly when the ferro-elasticity is obvious.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040938
|
oai_dc
|
Design, analyses, and evaluation of a spiral TDR sensor with high spatial resolution
|
Design, analyses, and evaluation of a spiral TDR sensor with high spatial resolution
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Quan Gao(Case Western Reserve University); Guangxi Wu(Case Western Reserve University); Xiong Yu(Case Western Reserve University)"
] |
Time Domain Reflectometry (TDR) has been extensively applied for various laboratory and field studies. Numerous different TDR probes are currently available for measuring soil moisture content and detecting interfaces (i.e., due to landslides or structural failure). This paper describes the development of an innovative spiral-shaped TDR probe that features much higher sensitivity and resolution in detecting interfaces than existing ones. Finite element method (FEM) simulations were conducted to assist the optimization of sensor design. The influence of factors such as wire interval spacing and wire diameter on the sensitivity of the spiral TDR probe were analyzed. A spiral TDR probe was fabricated based on the results of computer-assisted design. A laboratory experimental program was implemented to evaluate its performance. The results show that the spiral TDR sensor featured excellent performance in accurately detecting thin water level variations with high resolution, to the thickness as small as 0.06 cm. Compared with conventional straight TDR probe, the spiral TDR probe has 8 times the resolution in detecting the water level changes. It also achieved 3 times the sensitivity of straight TDR probe.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040925
|
oai_dc
|
Wideband and 2D vibration energy harvester using multiple magnetoelectric transducers
|
Wideband and 2D vibration energy harvester using multiple magnetoelectric transducers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jin Yang(Research Center of Sensors and Instruments); Qiangmo Yu(Research Center of Sensors and Instruments); Jiangxin Zhao(Research Center of Sensors and Instruments); Nian Zhao(Research Center of Sensors and Instruments); Yumei Wen(Research Center of Sensors and Instruments); Ping Li (Research Center of Sensors and Instruments)"
] |
This paper investigates a magnetoelectric (ME) vibration energy harvester that can scavenge energy in arbitrary directions in a plane as well as wide working bandwidth. In this harvester, a circular cross-section cantilever rod is adopted to extract the external vibration energy due to the capability of it\'s free end oscillating in arbitrary in-plane directions. And permanent magnets are fixed to the free end of the cantilever rod, causing it to experience a non-linear force as it moves with respect to stationary ME transducers and magnets. The magnetically coupled cantilever rod exhibits a nonlinear and two-mode motion, and responds to vibration over a much broader frequency range than a standard cantilever. The effects of the magnetic field distribution and the magnetic force on the harvester\'s voltage response are investigated with the aim to obtain the optimal vibration energy harvesting performances. A prototype harvester was fabricated and experimentally tested, and the experimental results verified that the harvester can extract energy from arbitrary in-plane directions, and had maximum bandwidth of 5.5 Hz, and output power of 0.13 mW at an acceleration of 0.6 g (with g=9.8 ms-2).
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040937
|
oai_dc
|
Scour-monitoring techniques for offshore foundations
|
Scour-monitoring techniques for offshore foundations
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yong-Hoon Byun(Korea University); Kiwon Park(Korea University); 이종섭(고려대학교)"
] |
The scour induced by strong currents and wave action decreases the embedded length of monopiles and leads to a decrease of their structural stability. The objective of this study is the development and consideration of scour-monitoring techniques for offshore monopile foundations. Tests on physical models are carried out with a model monopile and geo-materials prepared in a cylindrical tank. A strain gauge, two coupled ultrasonic transducers, and ten electrodes are used for monitoring the scour. The natural frequency, ultrasonic reflection images, and electrical resistivity profiles are obtained at various scour depths. The experimental results show that the natural frequency of the model monopile decreases with an increase in the scour depth and that the ultrasonic reflection images clearly detect the scour shape and scour depth. In addition, the electrical resistivity decreases with an increase in scour depth. This study suggests that natural frequency measurement, ultrasonic reflection imaging, and electrical resistivity profiling may be used as effective tools to monitor the scour around an offshore monopile foundation.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040941
|
oai_dc
|
Performance of TMDs on nonlinear structures subjected to near-fault earthquakes
|
Performance of TMDs on nonlinear structures subjected to near-fault earthquakes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Martín Domizio(National University); Daniel Ambrosini(National University); Oscar Curadelli(National University)"
] |
Tuned mass dampers (TMD) are devices employed in vibration control since the beginning of the twentieth century. However, their implementation for controlling the seismic response in civil structures is more recent. While the efficiency of TMD on structures under far-field earthquakes has been demonstrated, the convenience of its employment against near-fault earthquakes is still under discussion. In this context, the study of this type of device is raised, not as an alternative to the seismic isolation, which is clearly a better choice for new buildings, but rather as an improvement in the structural safety of existing buildings. Seismic records with an impulsive character have been registered in the vicinity of faults that cause seismic events. In this paper, the ability of TMD to control the response of structures that experience inelastic deformations and eventually reach collapse subject to the action of such earthquakes is studied.
The results of a series of nonlinear dynamic analyses are presented. These analyses are performed on a numerical model of a structure under the action of near-fault earthquakes. The structure analyzed in this study is a steel frame which behaves as a single degree of freedom (SDOF) system. TMD with different mass values are added on the numerical model of the structure, and the TMD performance is evaluated by comparing the response of the structure with and without the control device.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040927
|
oai_dc
|
Application of self-healing technique to fibre reinforced polymer wind turbine blade
|
Application of self-healing technique to fibre reinforced polymer wind turbine blade
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Omosola Fifo(Trinity College Dublin); Kevin Ryan(Trinity College Dublin); Biswajit Basu(Trinity College Dublin)"
] |
This paper presents a novel concept of healing some of the damages in wind turbine blades (WTBs) such as cracks and delamination. This is achieved through an inherent functioning autonomous repairing system. Such wind turbine blades have the benefit of reduced maintenance cost and increased operational period. Previous techniques of developing autonomous healing systems uses hollow glass fibres (HGFs) to deliver repairing fluids to damaged sites. HGFs have been reported with some limitations like, failure to fracture, which undermines their further usage. The self-healing technique described in this paper represents an advancement in the engineering of the delivery mechanism of a self-healing system. It is analogous to the HGF system but without the HGFs, which are replaced by multiple hollow channels created within the composite, inherently in the FRP matrix at fabrication. An in-house fabricated NACA 4412 WTB incorporating this array of network hollow channels was damaged in flexure and then autonomously repaired using the vascular channels. The blade was re-tested under flexure to ascertain the efficiency of the recovered mechanical properties.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002040940
|
oai_dc
|
Comparison of seismic behavior of long period SDOF systems mounted on friction isolators under near-field earthquakes
|
Comparison of seismic behavior of long period SDOF systems mounted on friction isolators under near-field earthquakes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vahid Loghman(AmirKabir University); Faramarz Khoshnoudian(AmirKabir University)"
] |
Friction isolators are one of the most important types of bearings used to mitigate damages of earthquakes. The adaptive behavior of these isolators allows them to achieve multiple levels of performances and predictable seismic behavior during different earthquake hazard levels. There are three main types of friction isolators. The first generation with one sliding surface is known as Friction Pendulum System (FPS) isolators. The double concave friction pendulum (DCFP) with two sliding surfaces is an advanced form of FPS, and the third one, with fully adaptive behavior, is named as triple concave friction pendulum (TCFP). The current study has been conducted to investigate and compare seismic responses of these three types of isolators. The structure is idealized as a two-dimensional single degree of freedom (SDOF) resting on isolators. The coupled differential equations of motion are derived and solved using state space formulation. Seismic responses of isolated structures using each one of these isolators are investigated under seven near fault earthquake motions. The peak values of bearing displacement and base shear are studied employing the variation of essential parameters such as superstructure period, effective isolation period and effective damping of isolator. The results demonstrate a more efficient seismic behavior of TCFP isolator comparing to the other types of isolators. This efficiency depends on the selected effective isolation period as well as effective isolation damping. The investigation shows that increasing the effective isolation period or decreasing the effective isolation damping improves the seismic behavior of TCFP compared to the other isolators. The maximum difference in seismic responses, the base shear and the bearing displacement, for the TCFP isolator are calculated 26.8 and 13.4 percent less than the DCFP and FPS in effective isolation damping equal to10%, respectively.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128781
|
oai_dc
|
Perturbation method for the dynamic analysis of a bistable oscillator under slow harmonic excitation
|
Perturbation method for the dynamic analysis of a bistable oscillator under slow harmonic excitation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Angelo Luongo(University of L'Aquila); Sara Casciati(University of Catania); Daniele Zulli(University of L'Aquila)"
] |
In this paper a nonlinear, bistable, single degree of freedom system is considered. It consists of a Duffing oscillator externally excited by a non-resonant, harmonic force. A customized perturbation scheme is proposed to achieve an approximate expression for periodic solutions. It is based on the evaluation of the quasi-steady (slow) solution, and then on a variable change followed by two perturbation steps which aim to capture the fast, decaying contribution of the response. The reconstructed solution, given by the sum of the slow and fast contributions, is in a good agreement with the one obtained by numerical integration.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128764
|
oai_dc
|
An experimental study of vibration control of wind-excited high-rise buildings using particle tuned mass dampers
|
An experimental study of vibration control of wind-excited high-rise buildings using particle tuned mass dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zheng Lu(Tongji University); Dianchao Wang(Tongji University); Sami F. Masri(University of Southern California); Xilin Lu(Tongji University)"
] |
A particle tuned mass damper (PTMD) system is the combination of a traditional tuned mass damper (TMD) and a particle damper (PD). This paper presents the results of an experimental and analytical study of the damping performance of a PTMD attached to the top of a benchmark model under wind load excitation. The length ratio of the test model is 1:200. The vibration reduction laws of the system were explored by changing some system parameters (including the particle material, total auxiliary mass ratio, the mass ratio between container and particles, the suspending length, and wind velocity). An appropriate analytical solution based on the concept of an equivalent single-unit impact damper is presented. Comparison between the experimental and analytical results shows that, with the proper use of the equivalent method, reasonably accurate estimates of the dynamic response of a primary system under wind load excitation can be obtained. The experimental and simulation results show the robustness of the new damper and indicate that the damping performance can be improved by controlling the particle density, increasing the amount of particles, and aggravating the impact of particles etc.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128761
|
oai_dc
|
Active tendon control of suspension bridges
|
Active tendon control of suspension bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"André Preumont(Université Libre de Bruxelles (ULB)); Matteo Voltan(Polytecnico di Milano, 1); Andrea Sangiovanni(Polytecnico di Milano, 1); Bilal Mokrani(Université Libre de Bruxelles (ULB)); David Alaluf(Université Libre de Bruxelles (ULB))"
] |
The paper first reviews the theory of active tendon control with decentralized Integral Force Feedback (IFF) and collocated displacement actuator and force sensor; a formal proof of the formula giving the maximum achievable damping is provided for the first time. Next, the potential of the control strategy for the control of suspension bridges with active stay cables is evaluated on a numerical model of an existing footbridge; several configurations are investigated where the active cables connect the pylon to the deck or the deck to the catenary. The analysis confirms that it is possible to provide a set of targeted modes with a considerable amount of damping, reaching s=15% . Finally, the control strategy is demonstrated experimentally on a laboratory mock-up equipped with four control stay cables equipped with piezoelectric actuators. The experimental results confirm the excellent performance and robustness of the control system and the very good agreement with the predictions.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128779
|
oai_dc
|
Displacement tracking of pre-deformed smart structures
|
Displacement tracking of pre-deformed smart structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hans Irschik(Johannes Kepler University of Linz); Michael Krommer(Vienna University of Technology); Christian Zehetner(Linz Center of Mechatronics)"
] |
This paper is concerned with the dynamics of hyperelastic solids and structures. We seek for a smart control actuation that produces a desired (prescribed) displacement field in the presence of transient imposed forces. In the literature, this problem is denoted as displacement tracking, or also as shape morphing problem. One talks about shape control, when the displacements to be tracked do vanish. In the present paper, it is assumed that the control actuation is provided by imposed eigenstrains, e.g., by the electric field in piezoelectric actuators, or by thermal actuators, or via analogous physical effects, such as magneto-striction or pre-stress. Structures with a controlled eigenstrain-type actuation belong to the class of smart structures. The action of the eigenstrains can be conveniently characterized by actuation stresses. Our theoretical derivations are performed in the framework of the theory of small incremental dynamic deformations superimposed upon a statically pre-deformed configuration of a hyperelastic solid or structure. We particularly ask for a distribution of incremental actuation stresses, such that the incremental displacements follow exactly a prescribed trajectory field, despite the imposed incremental forces are present. An exact solution of this problem is presented under the assumption that the actuation stresses can be tailored freely and applied everywhere within the body. Extending a Neumann-type solution strategy, it is shown that the actuation stresses due to the distributed control eigenstrains must satisfy certain quasi-static equilibrium conditions, where auxiliary body-forces and auxiliary surface tractions are to be taken into account. The latter auxiliary loading can be directly computed from the imposed forces and from the desired displacement field to be tracked. Hence, despite the problem is a dynamic one, a straightforward computation of proper actuator distributions can be obtained in the framework of quasi-static equilibrium conditions. Necessary conditions for the functioning of this concept are presented. Particularly, it must be required that the intermediate configuration is infinitesimally superstable. Previous results of our group for the case of shape control and displacement tracking in linear elastic structures are included as special cases. The high potential of the solution is demonstrated via Finite Element computations for an irregularly shaped four-corner plate in a state of plain strain.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128759
|
oai_dc
|
Dynamic transient analysis of systems with material nonlinearity: a model order reduction approach
|
Dynamic transient analysis of systems with material nonlinearity: a model order reduction approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"F. Casciati(University of Pavia); L. Faravelli(University of Pavia)"
] |
Model Order Reduction (MOR) denotes the theory by which one tries to catch a model of order lower than that of the real model. This is conveniently pursued in view of the design of an efficient structural control scheme, just passive within this paper. When the nonlinear response of the reference structural system affects the nature of the reduced model, making it dependent on the visited subset of the input-output space, standard MOR techniques do not apply. The mathematical theory offers some specific alternatives, which however involve a degree of sophistication unjustified in the presence of a few localized nonlinearities. This paper suggests applying standard MOR to the linear parts of the structural system, the interface remaining the original unreduced nonlinear components. A case study focused on the effects of a helicopter land crash is used to exemplify the proposal.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128760
|
oai_dc
|
Human induced vibration vs. cable-stay footbridge deterioration
|
Human induced vibration vs. cable-stay footbridge deterioration
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Casciati(University of Catania)"
] |
In this paper, the possibility of using human induced loading (HIL) to detect a decrease of tension in the cable-stays of an existing footbridge is investigated. First, a reliable finite elements model of an existing footbridge is developed by calibration with experimental data. Next, estimates of the tension in the cables are derived and their dependency on the modal features of the deck is investigated. The modelling of the HIL is briefly discussed and used to perform the nonlinear, large strain, dynamic finite elements analyses. The results of these analyses are assessed with focus on characterizing the time histories of the tension in the cables under pedestrian crossing and their effects on the deck response for different initial conditions. Finally, the control perspective is introduced in view of further research.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128765
|
oai_dc
|
Innovative modeling of tuned liquid column damper controlled structures
|
Innovative modeling of tuned liquid column damper controlled structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Alberto Di Matteo(Università degli Studi di Palermo); Mario Di Paola(Università degli Studi di Palermo); Antonina Pirrotta(Università degli Studi di Palermo)"
] |
In this paper a different formulation for the response of structural systems controlled by Tuned Liquid Column Damper (TLCD) devices is developed, based on the mathematical tool of fractional calculus. Although the increasing use of these devices for structural vibration control, it has been demonstrated that existing model may lead to inaccurate prediction of liquid motion, thus reflecting in a possible imprecise description of the structural response. For this reason the recently proposed fractional formulation introduced to model liquid displacements in TLCD devices, is here extended to deal with TLCD controlled structures under base excitations. As demonstrated through an extensive experimental analysis, the proposed model can accurately capture structural responses both in time and in frequency domain. Further, the proposed fractional formulation is linear, hence making identification of the involved parameters extremely easier.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128762
|
oai_dc
|
An experimental study on constructing MR secondary suspension for high-speed trains to improve lateral ride comfort
|
An experimental study on constructing MR secondary suspension for high-speed trains to improve lateral ride comfort
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.Q. Ni(The Hong Kong Polytechnic University); S.Q. Ye(The Hong Kong Polytechnic University); S.D. Song(Dalian University of Technology)"
] |
This paper presents an experimental study on constructing a tunable secondary suspension for high-speed trains using magneto-rheological fluid dampers (referred to as MR dampers hereafter), in the interest of improving lateral ride comfort. Two types of MR dampers (type-A and type-B) with different control ranges are designed and fabricated. The developed dampers are incorporated into a secondary suspension of a full-scale high-speed train carriage for rolling-vibration tests. The integrated rail vehicle runs at a series of speeds from 40 to 380 km/h and with different current inputs to the MR dampers. The dynamic performance of the two suspension systems and the ride comfort rating of the rail vehicle are evaluated using the accelerations measured during the tests. In this way, the effectiveness of the developed MR dampers for attenuating vibration is assessed. The type-A MR dampers function like a stiffness component, rather than an energy dissipative device, during the tests with different running speeds. While, the type-B MR dampers exhibit significant damping and high current input to the dampers may adversely affect the ride comfort. As part of an ongoing investigation on devising an effective MR secondary suspension for lateral vibration suppression, this preliminary study provides an insight into dynamic behavior of high-speed train secondary suspensions and unique full-scale experimental data for optimal design of MR dampers suitable for high-speed rail applications.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128763
|
oai_dc
|
Design and calibration of a semi-active control logic to mitigate structural vibrations in wind turbines
|
Design and calibration of a semi-active control logic to mitigate structural vibrations in wind turbines
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nicola Caterino(University of Naples); Christos T. Georgakis(Technical University of Denmark); Mariacristina Spizzuoco (University of Naples Federico II); Antonio Occhiuzzi(University of Naples)"
] |
The design of a semi-active (SA) control system addressed to mitigate wind induced structural demand to high wind turbine towers is discussed herein. Actually, the remarkable growth in height of wind turbines in the last decades, for a higher production of electricity, makes this issue pressing than ever. The main objective is limiting bending moment demand by relaxing the base restraint, without increasing the top displacement, so reducing the incidence of harmful \"p-delta\" effects. A variable restraint at the base, able to modify in real time its mechanical properties according to the instantaneous response of the tower, is proposed. It is made of a smooth hinge with additional elastic stiffness and variable damping respectively given by springs and SA magnetorheological (MR) dampers installed in parallel. The idea has been physically realized at the Denmark Technical University where a 1/20 scale model of a real, one hundred meters tall wind turbine has been assumed as case study for shaking table tests. A special control algorithm has been purposely designed to drive MR dampers. Starting from the results of preliminary laboratory tests, a finite element model of such structure has been calibrated so as to develop several numerical simulations addressed to calibrate the controller, i.e., to achieve as much as possible different, even conflicting, structural goals. The results are definitely encouraging, since the best configuration of the controller leaded to about 80% of reduction of base stress, as well as to about 30% of reduction of top displacement in respect to the fixed base case.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002128780
|
oai_dc
|
Nonlinear modelling and analysis of thin piezoelectric plates: Buckling and post-buckling behaviour
|
Nonlinear modelling and analysis of thin piezoelectric plates: Buckling and post-buckling behaviour
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Michael Krommer(Vienna University of Technology); Yury Vetyukov(Vienna University of Technology); Elisabeth Staudigl(Vienna University of Technology)"
] |
In the present paper we discuss the stability and the post-buckling behaviour of thin piezoelastic plates. The first part of the paper is concerned with the modelling of such plates. We discuss the constitutive modelling, starting with the three-dimensional constitutive relations within Voigt\'s linearized theory of piezoelasticity. Assuming a plane state of stress and a linear distribution of the strains with respect to the thickness of the thin plate, two-dimensional constitutive relations are obtained. The specific form of the linear thickness distribution of the strain is first derived within a fully geometrically nonlinear formulation, for which a Finite Element implementation is introduced. Then, a simplified theory based on the von Karman and Tsien kinematic assumption and the Berger approximation is introduced for simply supported plates with polygonal planform. The governing equations of this theory are solved using a Galerkin procedure and cast into a non-dimensional formulation. In the second part of the paper we discuss the stability and the post-buckling behaviour for single term and multi term solutions of the non-dimensional equations. Finally, numerical results are presented using the Finite Element implementation for the fully geometrically nonlinear theory. The results from the simplified von Karman and Tsien theory are then verified by a comparison with the numerical solutions.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133930
|
oai_dc
|
Cone penetrometer incorporated with dynamic cone penetration method for investigation of track substructures
|
Cone penetrometer incorporated with dynamic cone penetration method for investigation of track substructures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Won-Taek Hong(Korea University); Yong-Hoon Byun(University of Illinois at Urbana-Champaign); Sang Yeob Kim(Korea University); Jong-Sub Lee(Korea University)"
] |
The increased speed of a train causes increased loads that act on the track substructures. To ensure the safety of the track substructures, proper maintenance and repair are necessary based on an accurate characterization of strength and stiffness. The objective of this study is to develop and apply a cone penetrometer incorporated with the dynamic cone penetration method (CPD) for investigating track substructures. The CPD consists of an outer rod for dynamic penetration in the ballast layer and an inner rod with load cells for static penetration in the subgrade. Additionally, an energy-monitoring module composed of strain gauges and an accelerometer is connected to the head of the outer rod to measure the dynamic responses during the dynamic penetration. Moreover, eight strain gauges are installed in the load cells for static penetration to measure the cone tip resistance and the friction resistance during static penetration. To investigate the applicability of the developed CPD, laboratory and field tests are performed. The results of the CPD tests, i.e., profiles of the corrected dynamic cone penetration index (CDI), profiles of the cone tip and friction resistances, and the friction ratio are obtained at high resolution. Moreover, the maximum shear modulus of the subgrade is estimated using the relationships between the static penetration resistances and the maximum shear modulus obtained from the laboratory tests. This study suggests that the CPD test may be a useful method for the characterization of track substructures.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133939
|
oai_dc
|
Seismic isolation performance sensitivity to potential deviations from design values
|
Seismic isolation performance sensitivity to potential deviations from design values
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cenk Alhan(Istanbul University); Kemal Hisman(Istanbul University)"
] |
Seismic isolation is often used in protecting mission-critical structures including hospitals, data centers, telecommunication buildings, etc. Such structures typically house vibration-sensitive equipment which has to provide continued service but may fail in case sustained accelerations during earthquakes exceed threshold limit values. Thus, peak floor acceleration is one of the two main parameters that control the design of such structures while the other one is peak base displacement since the overall safety of the structure depends on the safety of the isolation system. And in case peak base displacement exceeds the design base displacement during an earthquake, rupture and/or buckling of isolators as well as bumping against stops around the seismic gap may occur. Therefore, obtaining accurate peak floor accelerations and peak base displacement is vital. However, although nominal design values for isolation system and superstructure parameters are calculated in order to meet target peak design base displacement and peak floor accelerations, their actual values may potentially deviate from these nominal design values. In this study, the sensitivity of the seismic performance of structures equipped with linear and nonlinear seismic isolation systems to the aforementioned potential deviations is assessed in the context of a benchmark shear building under different earthquake records with near-fault and far-fault characteristics. The results put forth the degree of sensitivity of peak top floor acceleration and peak base displacement to superstructure parameters including mass, stiffness, and damping and isolation system parameters including stiffness, damping, yield strength, yield displacement, and post-yield to pre-yield stiffness ratio.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133931
|
oai_dc
|
Percolation threshold and piezoresistive response of multi-wall carbon nanotube/cement composites
|
Percolation threshold and piezoresistive response of multi-wall carbon nanotube/cement composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"I.W. Nam(K-water Institute); H. Souri(The University of Auckland); H.K. Lee(KAIST)"
] |
The present work aims to develop piezoresistive sensors of excellent piezoresistive response attributable to change in nanoscale structures of multi-wall carbon nanotube (MWNT) embedded in cement. MWNT was distributed in a cement matrix by means of polymer wrapping method in tandem with the ultrasonication process. DC conductivity of the prepared samples exhibited the electrical percolation behavior and therefore the dispersion method adopted in this study was deemed effective. The integrity of piezoresistive response of the sensors was assessed in terms of stability, the maximum electrical resistance change rate, and sensitivity. A composite sensor with MWNT 0.2 wt.% showed the lowest stability and sensitivity, while the maximum electrical resistance change rate exhibited by this sample was the highest (96 %) among others and even higher than those found in the literature. This observation was presumably attributed by the percolation threshold and the tunneling effect. As a result of the MWNT content (0.2 wt.%) of the sensor being near the percolation threshold (0.25 wt.%), MWNTs were close to each other to trigger tunneling in response of external loading. The sensor with MWNT 0.2 wt.% was able to maintain the repeatable sensing capability while sustaining a vehicular loading on road, demonstrating the feasibility in traffic flow sensing application.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133935
|
oai_dc
|
Bimorph piezoelectric energy harvester structurally integrated on a trapezoidal plate
|
Bimorph piezoelectric energy harvester structurally integrated on a trapezoidal plate
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet Levent Avsar(Middle East Technical University); Melin Sahin(Middle East Technical University)"
] |
A bimorph piezoelectric energy harvester is developed for harvesting energy under the vortex induced vibration and it is integrated to a host structure of a trapezoidal plate without changing its passive dynamic properties. It is aimed to select trapezoidal plate as similar to a vertical fin-like structure which could be a part of an air vehicle. The designed energy harvester consists of an aluminum beam and two identical multi fiber composite (MFC) piezoelectric patches. In order to understand the dynamic characteristic of the trapezoidal plate, finite element analysis is performed and it is validated through an experimental study. The bimorph piezoelectric energy harvester is then integrated to the trapezoidal plate at the most convenient location with minimal structural displacement. The finite element model is constructed for the new combined structure in ANSYS Workbench 14.0 and the analyses performed on this particular model are then validated via experimental techniques. Finally, the energy harvesting performance of the bimorph piezoelectric energy harvester attached to the trapezoidal plate is also investigated through wind tunnel tests under the air load and the obtained results indicate that the system is a viable one for harvesting reasonable amount of energy.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133937
|
oai_dc
|
Thermal buckling response of functionally graded sandwich plates with clamped boundary conditions
|
Thermal buckling response of functionally graded sandwich plates with clamped boundary conditions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zohra Abdelhak(Université Ahmed Zabana); Lazreg Hadji(Université de Sidi Bel Abbes); T. Hassaine Daouadji(Université de Sidi Bel Abbes); E.A. Adda Bedia(Université de Sidi Bel Abbes)"
] |
In this research work, an exact analytical solution for thermal buckling analysis of functionally graded material (FGM) sandwich plates with clamped boundary condition subjected to uniform, linear, and non-linear temperature rises across the thickness direction is developed. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory accounts for parabolic distribution of the transverse shear strains, and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factor. A power law distribution is used to describe the variation of volume fraction of material compositions. Equilibrium and stability equations are derived based on the present refined theory. The non-linear governing equations are solved for plates subjected to simply supported and clamped boundary conditions. The thermal loads are assumed to be uniform, linear and non-linear distribution through-the-thickness. The effects of aspect and thickness ratios, gradient index, on the critical buckling are all discussed.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133933
|
oai_dc
|
Vibration characteristic analysis of sandwich cylindrical shells with MR elastomer
|
Vibration characteristic analysis of sandwich cylindrical shells with MR elastomer
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jia-Yi Yeh(Chung Hwa University of Medical Technology)"
] |
The vibration characteristic analysis of sandwich cylindrical shells subjected with magnetorheological (MR) elastomer and constraining layer are considered in this study. And, the discrete finite element method is adopted to calculate the vibration and damping characteristics of the sandwich cylindrical shell system. The effects of thickness of the MR elastomer, constraining layer, applied magnetic fields on the vibration characteristics of the sandwich shell system are also studied in this paper. Additionally, the rheological properties of the MR elastomer can be changed by applying various magnetic fields and the properties of the MR elastomer are described by complex quantities. The natural frequencies and modal loss factor of the sandwich cylindrical shells are calculated for many designed parameters. The core layer of MR elastomer is found to have significant effects on the damping behavior of the sandwich cylindrical shells.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133941
|
oai_dc
|
Structural health monitoring system for Sutong Cable-stayed Bridge
|
Structural health monitoring system for Sutong Cable-stayed Bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hao Wang(Southeast University); Tianyou Tao(Southeast University); Aiqun Li(Southeast University); Yufeng Zhang(Jiangsu Transportation Institute)"
] |
Structural Health Monitoring System (SHMS) works as an efficient platform for monitoring the health status and performance deterioration of engineering structures during long-term service periods. The objective of its installation is to provide reasonable suggestions for structural maintenance and management, and therefore ensure the structural safety based on the information extracted from the real-time measured data. In this paper, the SHMS implemented on a world-famous kilometer-level cable-stayed bridge, named as Sutong Cable-stayed Bridge (SCB), is introduced in detail. The composition and core functions of the SHMS on SCB are elaborately presented. The system consists of four main subsystems including sensory subsystem, data acquisition and transmission subsystem, data management and control subsystem and structural health evaluation subsystem. All of the four parts are decomposed to separately describe their own constitutions and connected to illustrate the systematic functions. Accordingly, the main techniques and strategies adopted in the SHMS establishment are presented and some extension researches based on structural health monitoring are discussed. The introduction of the SHMS on SCB is expected to provide references for the establishment of SHMSs on long-span bridges with similar features as well as the implementation of potential researches based on structural health monitoring.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133945
|
oai_dc
|
Transverse dynamics of slender piezoelectric bimorphs with resistive-inductive electrodes [Open access article]
|
Transverse dynamics of slender piezoelectric bimorphs with resistive-inductive electrodes [Open access article]
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Juergen Schoeftner(Johannes Kepler University); Gerda Buchberger(Johannes Kepler University); Ayech Benjeddou(SUPMECA)"
] |
This paper presents and compares a one-dimensional (1D) bending theory for piezoelectric thin beam-type structures with resistive-inductive electrodes to ANSYS three-dimensional (3D) finite element (FE) analysis. In particular, the lateral deflections and vibrations of slender piezoelectric beams are considered. The peculiarity of the piezoelectric beam model is the modeling of electrodes in such a manner that is does not fulfill the equipotential area condition. The case of ideal, perfectly conductive electrodes is a special case of our 1D model. Two-coupled partial differential equations are obtained for the lateral deflection and for the voltage distribution along the electrodes: the first one is an extended Bernoulli-Euler beam equation (second-order in time, forth order in space) and the second one the so-called Telegrapher\'s equation (second-order in time and space). Analytical results of our theory are validated by 3D electromechanically coupled FE simulations with ANSYS. A clamped-hinged beam is considered with various types of electrodes for the piezoelectric layers, which can be either resistive and/or inductive. A natural frequency analysis as well as quasi-static and dynamic simulations are performed. A good agreement between the extended beam theory and the FE results is found. Finally, the practical relevance of this type of electrodes is shown. It is found that the damping capability of properly tuned resistive or resistive-inductive electrodes exceeds the damping performance of beams, where the electrodes are simply linked to an optimized impedance.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART002133943
|
oai_dc
|
Slender piezoelectric beams with resistive-inductive electrodes – modeling and axial wave propagation
|
Slender piezoelectric beams with resistive-inductive electrodes – modeling and axial wave propagation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Juergen Schoeftner(Johannes Kepler University); Gerda Buchberger(Johannes Kepler University); Ayech Benjeddou(SUPMECA)"
] |
This contribution presents an extended one-dimensional theory for piezoelectric beam-type structures with non-ideal electrodes. For these types of electrodes the equipotential area condition is not satisfied. The main motivation of our research is originated from passive vibration control: when an elastic structure is covered by several piezoelectric patches that are linked via resistances and inductances, vibrational energy is efficiently dissipated if the electric network is properly designed. Assuming infinitely small piezoelectric patches that are connected by an infinite number of electrical, in particular resistive and inductive elements, one obtains the Telegrapher\'s equation for the voltage across the piezoelectric transducer. Embedding this outcome into the framework of Bernoulli-Euler, the final equations are coupled to the wave equations for the longitudinal motion of a bar and to the partial differential equations for the lateral motion of the beam. We present results for the wave propagation of a longitudinal bar for several types of electrode properties. The frequency spectra are computed (phase angle, wave number, wave speed), which point out the effect of resistive and inductive electrodes on wave characteristics. Our results show that electrical damping due to the resistivity of the electrodes is different from internal (=strain velocity dependent) or external (=velocity dependent) mechanical damping. Finally, results are presented, when the structure is excited by a harmonic single force, yielding that resistive-inductive electrodes are suitable candidates for passive vibration control that might be of great interest for practical applications in the future.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001789360
|
oai_dc
|
Piezoelectric nanocomposite sensors assembled using zinc oxide nanoparticles and poly(vinylidene fluoride)
|
Piezoelectric nanocomposite sensors assembled using zinc oxide nanoparticles and poly(vinylidene fluoride)
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"John S. Dodds(University of California); Kenneth J. Loh(University of California); Frederick N. Meyers(University of California)"
] |
Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for sensing and damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory/field tests and possess significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and SHM applications. These films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. This study started with spin coating dispersed ZnO- and PVDF-TrFE-based solutions to fabricate the piezoelectric nanocomposites. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5 % increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled (at 50 MV-m-1) to permanently align their electrical domains and to enhance their bulk film piezoelectricity. Then, a series of hammer impact tests were conducted, and the voltage generated by poled ZnO-based thin films was compared to commercially poled PVDF copolymer thin films. The hammer impact tests showed comparable results between the prototype and commercial samples, and increasing ZnO content provided enhanced piezoelectric performance. Lastly, the films were further validated for sensing using different energy levels of hammer impact, different distances between the impact locations and the film electrodes, and cantilever free vibration testing for dynamic strain sensing.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001789357
|
oai_dc
|
In situ analysis of capturing dynamics of magnetic nanoparticles in a microfluidic system
|
In situ analysis of capturing dynamics of magnetic nanoparticles in a microfluidic system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahsan Munir(Worcester Polytechnic Institute); H. Susan Zhou(Worcester Polytechnic Institute); Zanzan Zhu(Worcester Polytechnic Institute); Jianlong Wang(Northwest A&F University)"
] |
Magnetic nanoparticle based bioseparation in microfluidics is a multiphysics phenomenon that involves interplay of various parameters. The ability to understand the dynamics of these parameters is a prerequisite for designing and developing more efficient magnetic cell/bio-particle separation systems. Therefore, in this work proof-of-concept experiments are combined with advanced numerical simulation to design and optimize the capturing process of magnetic nanoparticles responsible for efficient microfluidic bioseparation. A low cost generic microfluidic platform was developed using a novel micromolding method that can be done without a clean room techniques and at much lower cost and time. Parametric analysis using both experiments and theoretical predictions were performed. It was found that flow rate and magnetic field strength greatly influence the transport of magnetic nanoparticles in the microchannel and control the capturing efficiency. The results from mathematical model agree very well with experiments. The model further demonstrated that a 12% increase in capturing efficiency can be achieved by introducing of iron-grooved bar in the microfluidic setup that resulted in increase in magnetic field gradient. The numerical simulations were helpful in testing and optimizing key design parameters. Overall, this work demonstrated that a simple low cost experimental proof-of-concept setup can be synchronized with advanced numerical simulation not only to enhance the functional performance of magneto-fluidic capturing systems but also to efficiently design and develop microfluidic bioseparation systems for biomedical applications.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001789358
|
oai_dc
|
Investigation of smart multifunctional optical sensor platform and its application in optical sensor networks
|
Investigation of smart multifunctional optical sensor platform and its application in optical sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. Pang(University of Maryland); M. Yu(University of Maryland); A.K. Gupta(University of Maryland); K.M. Bryden(Iowa State University)"
] |
In this article, a smart multifunctional optical system-on-a-chip (SOC) sensor platform is presented and its application for fiber Bragg grating (FBG) sensor interrogation in optical sensor networks is investigated. The smart SOC sensor platform consists of a superluminescent diode as a broadband source, a tunable microelectromechanical system (MEMS) based Fabry-Pérot filter, photodetectors, and an integrated microcontroller for data acquisition, processing, and communication. Integrated with a wireless sensor network (WSN) module in a compact package, a smart optical sensor node is developed. The smart multifunctional sensor platform has the capability of interrogating different types of optical fiber sensors, including Fabry-Pérot sensors and Bragg grating sensors. As a case study, the smart optical sensor platform is demonstrated to interrogate multiplexed FBG strain sensors. A time domain signal processing method is used to obtain the Bragg wavelength shift of two FBG strain sensors through sweeping the MEMS tunable Fabry-Pérot filter. A tuning range of 46 nm and a tuning speed of 10 Hz are achieved. The smart optical sensor platform will open doors to many applications that require high performance optical WSNs.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001789361
|
oai_dc
|
DNA-functionalized single-walled carbon nanotube-based sensor array for gas monitoring
|
DNA-functionalized single-walled carbon nanotube-based sensor array for gas monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wenjun Zhang(Northeastern University); Yu Liu(Northeastern University); Ming. L Wang(Northeastern University)"
] |
Nine deoxyribonucleic acid (DNA) sequences were used to functionalize single-walled carbon nanotube (SWNT) sensors to detect the trace amount of methanol, acetone, and HCl in vapor. DNA 24 Ma (24 randomly arranged nitrogenous bases with one amine at each end of it) decorated SWNT sensor and DNA 24 A (only adenine (A) base with a length of 24) decorated SWNT sensor have demonstrated the largest sensing responses towards acetone and HCl, respectively. On the other hand, for the DNA GT decorated SWNT sensors with different sequence lengths, the optimum DNA sequence length for acetone and HCl sensing is 32 and 8, separately. The detection of methanol, acetone, and HCl have identified that DNA functionalized SWNT sensors exhibit great selectivity, sensitivity, and repeatability with an accuracy of more than 90%. Further, a sensor array composed of SWNT functionalized with various DNA sequences was utilized to identify acetone and HCl through pattern recognition. The sensor array is a combination of four different DNA functionalized SWNT sensors and two bare SWNT sensors (work as reference). This wireless sensing system has enabled real-time gas monitoring and air quality assurance for safety and security.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001789359
|
oai_dc
|
A novel Fabry-Perot fiber optic temperature sensor for early age hydration heat study in Portland cement concrete
|
A novel Fabry-Perot fiber optic temperature sensor for early age hydration heat study in Portland cement concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiaotian Zou(University of Massachusetts); Xingwei Wang(University of Massachusetts); Alice Chao(University of Massachusetts); Nan Wu(University of Massachusetts); Tzu-Yang Yu(University of Massachusetts)"
] |
Concrete is known as a heterogeneous product which is composed of complex chemical composition and reaction. The development of concrete thermal effect during early age is critical on its future structural health and long term durability. When cement is mixed with water, the exothermic chemical reaction generates hydration heat, which raises the temperature within the concrete. Consequently, cracking may occur if the concrete temperature rises too high or if there is a large temperature difference between the interior and the exterior of concrete structures during early age hydration. This paper describes the contribution of novel Fabry-Perot (FP) fiber optic temperature sensors to investigate the thermal effects of concrete hydration process. Concrete specimens were manufactured under various water-to-cement (w/c) ratios from 0.40 to 0.60. During the first 24 hours of concreting, two FP fiber optic temperature sensors were inserted into concrete specimens with the protection of copper tubing to monitor the surface and core temperature change. The experimental results revealed effects of w/c ratios on surface and core temperature developments during early age hydration, as well as demonstrating that FP fiber optic sensors are capable of capturing temperature variation in the concrete with reliable performance. Temperature profiles are used for calculating the apparent activation energy (Ea) and the heat of hydration (H(t)) of concrete, which can help us to better understand cement hydration.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001775725
|
oai_dc
|
Structural health monitoring of the Jiangyin Bridge: system upgrade and data analysis
|
Structural health monitoring of the Jiangyin Bridge: system upgrade and data analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"H.F. Zhou(Wenzhou University); Y.Q. Ni(The Hong Kong Polytechnic University); J.M. Ko(The Hong Kong Polytechnic University)"
] |
The Jiangyin Bridge is a suspension bridge with a main span of 1385 m over the Yangtze River in Jiangsu Province, China. Being the first bridge with a main span exceeding 1 km in Chinese mainland, it had been instrumented with a structural health monitoring (SHM) system when completed in 1999. After operation for several years, it was found with malfunction in sensors and data acquisition units, and insufficient sensors to provide necessary information for structural health evaluation. This study reports the SHM system upgrade project on the Jiangyin Bridge. Although implementations of SHM system have been reported worldwide, few studies are available on the upgrade of SHM system so far. Recognizing this, the upgrade of original SHM system for the bridge is first discussed in detail. Especially, lessons learned from the original SHM system are applied to the design of upgraded SHM system right away. Then, performance assessment of the bridge, including: (i) characterization of temperature profiles and effects; (ii) recognition of wind characteristics and effects; and (iii) identification of modal properties, is carried out by making use of the long-term monitoring data obtained from the upgraded SHM system. Emphasis is placed on the verification of design assumptions and prediction of bridge behavior or extreme responses. The results may provide the baseline for structural health evaluation.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001775715
|
oai_dc
|
Experimental evaluation of discrete sliding mode controller for piezo actuated structure with multisensor data fusion
|
Experimental evaluation of discrete sliding mode controller for piezo actuated structure with multisensor data fusion
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Arunshankar(PSG College of Technology); M. Umapathy(National Institute of Technology); B. Bandhopadhyay(Indian Institute of Technology Bombay)"
] |
This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001775720
|
oai_dc
|
A full-range hybrid device for sound reproduction
|
A full-range hybrid device for sound reproduction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Francesco Braghin(Politecnico di Milano); Francesco Castelli-Dezza(Politecnico di Milano); Simone Cinquemani(Politecnico di Milano); Ferruccio Resta(Politecnico di Milano)"
] |
The paper deals with the design of a device for sound reproduction to be fixed to a supporting surface. The device is made up of two different types of acoustic actuators based on different technologies. This allows to reproduce sound in the range of frequencies from 20 Hz to 20 kHz. The generation of sound at high frequencies is demanded to a magnetostrictive actuator, while a more traditional magnetodynamics actuator is used to generate sound at low frequencies. The coupling between these two actuators leads to a device having small overall dimensions and high performance.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001775717
|
oai_dc
|
Reduced wavelet component energy-based approach for damage detection of jacket type offshore platform
|
Reduced wavelet component energy-based approach for damage detection of jacket type offshore platform
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sajad Shahverdi(University of Tabriz); Mohammad Ali Lotfollahi-Yaghin(University of Tabriz); Behrouz Asgarian(K.N. Toosi University of Technology)"
] |
Identification of damage has become an evolving area of research over the last few decades with increasing the need of online health monitoring of the large structures. The visual damage detection can be impractical, expensive and ineffective in case of large structures, e.g., offshore platforms, offshore pipelines, multi-storied buildings and bridges. Damage in a system causes a change in the dynamic properties of the system. The structural damage is typically a local phenomenon, which tends to be captured by higher frequency signals. Most of vibration-based damage detection methods require modal properties that are obtained from measured signals through the system identification techniques. However, the modal properties such as natural frequencies and mode shapes are not such good sensitive indication of structural damage.
Identification of damaged jacket type offshore platform members, based on wavelet packet transform is presented in this paper. The jacket platform is excited by simple wave load. Response of actual jacket needs to be measured. Dynamic signals are measured by finite element analysis result. It is assumed that this is actual response of the platform measured in the field. The dynamic signals first decomposed into wavelet packet components. Then eliminating some of the component signals (eliminate approximation component of wavelet packet decomposition), component energies of remained signal (detail components) are calculated and used for damage assessment. This method is called Detail Signal Energy Rate Index (DSERI). The results show that reduced wavelet packet component energies are good candidate indices which are sensitive to structural damage. These component energies can be used for damage assessment including identifying damage occurrence and are applicable for finding damages' location.
|
토목공학
| null |
kci_detailed_000089.xml
|
|||
ART001775722
|
oai_dc
|
Active vibration suppression of a 1D piezoelectric bimorph structure using model predictive sliding mode control
|
Active vibration suppression of a 1D piezoelectric bimorph structure using model predictive sliding mode control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김병일(현대기아자동차); Gregory N. Washington(University of California); 윤환식(The University of Alabama)"
] |
This paper investigates application of a control algorithm called model predictive sliding mode control (MPSMC) to active vibration suppression of a cantilevered aluminum beam. MPSMC is a relatively new control algorithm where model predictive control is employed to enhance sliding mode control by enforcing the system to reach the sliding surface in an optimal manner. In previous studies, it was shown that MPSMC can be applied to reduce hysteretic effects of piezoelectric actuators in dynamic displacement tracking applications. In the current study, a cantilevered beam with unknown mass distribution is selected as an experimental test bed in order to verify the robustness of MPSMC in active vibration control applications. Experimental results show that MPSMC can reduce vibration of an aluminum cantilevered beam at least by 29% regardless of modified mass distribution.
|
토목공학
| null |
kci_detailed_000090.xml
|
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