id
stringlengths 12
12
| format
stringclasses 2
values | title_ko
stringlengths 0
811
⌀ | title_en
stringlengths 0
1.26k
⌀ | journal
dict | authors
listlengths 0
15
| abstract_ko
stringlengths 0
4k
⌀ | abstract_en
stringclasses 100
values | keywords
stringclasses 157
values | citation_count
stringclasses 5
values | doi
stringlengths 0
127
⌀ | url
stringclasses 101
values | file_source
stringlengths 23
23
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|
ART001497196
|
oai_dc
|
A review of health and operation monitoring technologies for trains
|
A review of health and operation monitoring technologies for trains
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"See Yenn Chong(Chonbuk National University); 이정율(전북대학교); Hye-Jin Shin(Chonbuk National University)"
] |
Railway transport of goods and passengers is effective in terms of energy conservation and travel time savings. Safety and ride quality have become important issues as train speeds have increased. Due to increased speeds, minor damage to railway structures and abnormal interactions between trains and structures have given rise to increasingly serious accidents. Therefore, structural health and operational conditions must be monitored continuously in all service environments. Currently, various health and operation management systems are being developed and these are reducing both maintenance frequency and costs associated with disassembly. In this review, major damage and malfunctions and their locations are first analyzed based on numerous references. Then advanced train health and operation management technologies are classified into wayside detection methods and advanced integrated sensor methods and their operating principle and functions are reviewed and analyzed.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470249
|
oai_dc
|
Non-destructive evaluation of concrete quality using PZT transducers
|
Non-destructive evaluation of concrete quality using PZT transducers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Tawie(KAIST); 이행기(한국과학기술원); S.H. Park(Sungkyunkwan University)"
] |
This paper presents a new concept of using PZT (lead zircornate titanate) transducers as a non-destructive testing (NDT) tool for evaluating quality of concrete. Detection of defects in concrete is very important in order to check the integrity of concrete structures. The electro-mechanical impedance (EMI) response of PZT transducers bonded onto a concrete specimen can be used for evaluating local condition of the specimen. Measurements are carried out by electrically exciting the bonded PZT transducers at high frequency range and taking response measurements of the transducers. In this study, the compression test results showed that concrete specimens without sufficient compaction are likely to fall below the desired strength. In addition, the strength of concrete was greatly reduced as the voids in concrete were increased. It was found that the root mean square deviation (RMSD) values yielded between the EMI signatures for concrete specimens in dry and saturated states showed good agreement with the specimens compressive strength and permeable voids. A quality metric was introduced for predicting the quality of concrete based on the dry-saturated state of concrete specimens. The simplicity of the method and the current development towards low cost and portable impedance measuring system, offer an advantage over other NDE methods for evaluating concrete quality.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470242
|
oai_dc
|
Integrated vibration control and health monitoring of building structures: a time-domain approach
|
Integrated vibration control and health monitoring of building structures: a time-domain approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"B. Chen(The Hong Kong Polytechnic University); Y.L. Xu(The Hong Kong Polytechnic University); X. Zhao(The Hong Kong Polytechnic University)"
] |
Vibration control and health monitoring of building structures have been actively investigated in recent years but treated separately according to the primary objective pursued. This paper presents a general approach in the time domain for integrating vibration control and health monitoring of a building structure to accommodate various types of control devices and on-line damage detection. The concept of the time-domain approach for integrated vibration control and health monitoring is first introduced. A parameter identification scheme is then developed to identify structural stiffness parameters and update the structural analytical model. Based on the updated analytical model, vibration control of the building using semi-active friction dampers against earthquake excitation is carried out. By assuming that the building suffers certain damage after extreme event or long service and by using the previously identified original structural parameters, a damage detection scheme is finally proposed and used for damage detection. The feasibility of the proposed approach is demonstrated through detailed numerical examples and extensive parameter studies.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470238
|
oai_dc
|
Semi-analytical solutions for optimal distributions of sensors and actuators in smart structure vibration control
|
Semi-analytical solutions for optimal distributions of sensors and actuators in smart structure vibration control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhanli Jin(Nanyang Technological University); Yaowen Yang(Nanyang Technological University); Chee Kiong Soh(Nanyang Technological University)"
] |
In this paper, the optimal design of vibration control system for smart structures has been investigated semi-analytically via the optimization of geometric parameters like the placements and sizes of piezoelectric sensors and actuators (S/As) bonded on the structures. The criterion based on the maximization of energy dissipation was adopted for the optimization of the control system. Based on the sensing and actuating equations, the total energy stored in the system which is used as the objective function was analytically derived with design variables explicitly presented. Two cases of single and combined vibration modes were addressed for a simply supported beam and a simply supported cylindrical shell. For single vibration mode, the optimal distributions of the piezoelectric S/As could be obtained analytically. However, the Sequential Quadratic Programming (SQP) method has to be employed to solve those which violated the prescribed constraints and to solve the case of combined vibration modes. The results of three examples, which include a simply supported beam, a simply supported cylindrical shell and a simply supported plate, showed good agreement with those obtained by the Genetic Algorithm (GA) method. Moreover, in comparison with the GA method, the proposed method is more effective in obtaining better optimization results and is much more efficient in terms of computation time.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470246
|
oai_dc
|
Piezo-activated guided wave propagation and interaction with damage in tubular structures
|
Piezo-activated guided wave propagation and interaction with damage in tubular structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ye Lu(Shanghai Jiao Tong University); Lin Ye(The University of Sydney); Dong Wang(The University of Sydney); Limin Zhou(The Hong Kong Polytechnic University); Li Cheng(The Hong Kong Polytechnic University)"
] |
This study investigated propagation characteristics of piezo-activated guided waves in an aluminium rectangular-section tube for the purpose of damage identification. Changes in propagating velocity and amplitude of the first wave packet in acquired signals were observed in the frequency range from 50 to 250 kHz. The difference in guided wave propagation between rectangular- and circular-section tubes was examined using finite element simulation, demonstrating a great challenge in interpretation of guided wave signals in rectangular-section tubes. An active sensor network, consisting of nine PZT elements bonded on different surfaces of the tube, was configured to collect the wave signals scattered from through-thickness holes of different diameters. It was found that guided waves were capable of propagating across the sharp tube curvatures while retaining sensitivity to damage, even that not located on the surfaces where actuators/sensors were attached. Signal correlation between the intact and damaged structures was evaluated with the assistance of a concept of digital damage fingerprints (DDFs). The probability of the presence of damage on the unfolded tube surface was thus obtained, by which means the position of damage was identified with good accuracy.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470252
|
oai_dc
|
A dragonfly inspired flapping wing actuated by electro active polymers
|
A dragonfly inspired flapping wing actuated by electro active polymers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sujoy Mukherjee(Indian Institute of Science); Ranjan Ganguli(Indian Institute of Science)"
] |
An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001470240
|
oai_dc
|
On the control of vibratory MEMS gyroscopes
|
On the control of vibratory MEMS gyroscopes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Choura(University of Sfax); N. Aouni(University of Houston); S. El-Borgi(Tunisia Polytechnic School)"
] |
This paper addresses the control issue of vibratory MEMS-based gyroscopes. This study considers a gyroscope that can be modeled by an inner mass attached to an outer mass by four springs and four dampers. The outer mass itself is attached to the rotating frame by an equal number of springs and dampers. In order to measure the angular rate of the rotating frame, a driving force is applied to the inner mass and the Coriolis force is sensed along the y-direction associated with the outer mass. Due to micro-fabrication imperfections, including anisoelasticity and damping effects, both gyroscopes do not allow accurate measurements, and therefore, it becomes necessary to devise feedback controllers to reduce the effects of such imperfections. Given an ideal gyroscope that meets certain performance specifications, a feedback control strategy is synthesized to reduce the error dynamics between the actual and ideal gyroscopes. For a dual-mass gyroscope, it is demonstrated that the error dynamics are remarkably decreased with the application of four actuators applied to both masses in the x and y directions. It is also shown that it is possible to reduce the error dynamics with only two actuators applied to the outer mass only. Simulation results are presented to prove the efficiency of the proposed control design.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544781
|
oai_dc
|
Monitoring of tension force and load transfer of groundanchor by using optical FBG sensors embedded tendon
|
Monitoring of tension force and load transfer of groundanchor by using optical FBG sensors embedded tendon
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Young-Sang Kim(Chonnam National University); 김재민(전남대학교); Hyun-Jong sung(Chonnam National University); Hyun-Woo Kim(Chonnam National University)"
] |
A specially designed tendon, which is proposed by embedding an FBG sensor into the center king cable of a 7-wire strand tendon, was applied to monitor the prestress force and load transfer of ground anchor. A series of tensile tests and a model pullout test were performed to verify the feasibility of the proposed smart tendon as a measuring sensor of tension force and load transfer along the tendon. The smart tendon has proven to be very effective for monitoring prestress force and load transfer by measuring the strain change of the tendon at the free part and the fixed part of ground anchor, respectively. Two 11.5 m long proto-type ground anchors were made simply by replacing a tendon with the proposed smart tendon and prestress forces of each anchor were monitored during the loading-unloading step using both FBG sensor embedded in the smart tendon and the conventional load cell. By comparing the prestress forces measured by the smart tendon and load cell, it was found that the prestress force monitored from the FBG sensor located at the free part is comparable to that measured from the conventional load cell. Furthermore, the load transfer of prestressing force at the tendon-grout interface was clearly measured from the FBGs distributed along the fixed part. From these pullout tests, the proposed smart tendon is not only expected to be an alternative monitoring tool for measuring prestress force from the introducing stage to the long-term period for health monitoring of the ground anchor but also can be used to improve design practice through determining the economic fixed length by practically measuring the load transfer depth.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544777
|
oai_dc
|
Ultrasonic characterization of exhumed cast ironwater pipes
|
Ultrasonic characterization of exhumed cast ironwater pipes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Paul Groves(University of Waterloo); Giovanni Cascante(University of Waterloo); Mark Knight(University of Waterloo)"
] |
Cast iron pipe has been used as a water distribution technology in North America since the early nineteenth century. The first cast iron pipes were made of grey cast iron which was succeeded by ductile iron as a pipe material in the 1940s. These different iron alloys have significantly different microstructures which give rise to distinct mechanical properties. Insight into the non-destructive structural condition assessment of aging pipes can be advantageous in developing mitigation strategies for pipe failures. This paper examines the relationship between the small-strain and large-strain properties of exhumed cast iron water pipes. Nondestructive and destructive testing programs were performed on eight pipes varying in age from 40 to 130 years. The experimental program included microstructure evaluation and ultrasonic, tensile, and flexural testing. New applications of frequency domain analysis techniques including Fourier and wavelet transforms of ultrasonic pulse velocity measurements are presented. A low correlation between wave propagation and large-strain measurements was observed. However, the wave velocities were consistently different between ductile and grey cast iron pipes (14% to 18% difference); the ductile iron pipes showed the smaller variation in wave velocities. Thus, the variation of elastic properties for ductile iron was not enough to define a linear correlation because all the measurements were practically concentrated in single cluster of points. The cross-sectional areas of the specimens tested varied as a result of minor manufacturing defects and levels of corrosion. These variations affect the large strain testing results; but, surface defects have limited effect on wave velocities and may also contribute to the low correlations observed. Lamb waves are typically not considered in the evaluation of ultrasonic pulse velocity. However, Lamb waves were found to contribute significantly to the frequency content of the ultrasonic signals possibly resulting in the poor correlations observed. Therefore, correlations between wave velocities and large strain properties obtained using specimens manufactured in the laboratory must be used with caution in the condition assessment of aged water pipes especially for grey cast iron pipes.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544782
|
oai_dc
|
Measurements of dielectric constants of soil to develop a landslide prediction system
|
Measurements of dielectric constants of soil to develop a landslide prediction system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"임홍철(Yonsei University)"
] |
In this study, the measurements of the dielectric constants of soil at 900 MHz and 1 GHz were made to relate those properties to the moisture content of the soil. This study’s intention was to use the relationship between the dielectric constant and the moisture content to develop a landslide prediction system. By monitoring the change of the moisture content within the soil using ground penetrating radar (GPR) systems in the field, the possibility of a landslide is expected to be detected. To establish a database for the dielectric constants and the moisture content, the measurements of soil samples were made using both an open-ended dielectric coaxial probe and the GPR. Based on the measurement results, correlations between the GPR and reflector for each frequency at 900 MHz and 1 GHz were found for the dielectric constants and the moisture content. Finally, the mechanism of the measurement device to be implemented in the field is suggested.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544780
|
oai_dc
|
An experimental procedure for evaluating the consolidationstate of marine clay deposits using shear wave velocity
|
An experimental procedure for evaluating the consolidationstate of marine clay deposits using shear wave velocity
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"장일한(KAIST); 권태혁(Lawrence Berkeley National Laboratory); 조계춘(KAIST)"
] |
In marine clay deposits, naturally formed or artificially reclaimed, the evaluation and monitoring of the consolidation process has been a critical issue in civil engineering practices due to the time frame required for completing the consolidation process, which range from several days to several years. While complementing the conventional iconographic method suggested by Casagrande and recently developed in-situ techniques that measure the shear wave, this study suggests an alternative experimental procedure that can be used to evaluate the consolidation state of marine clay deposits using the shear wave velocity. A laboratory consolidation testing apparatus was implemented with bimorph-type piezoelectric bender elements to determine the effective stress-shear wave velocity (σ'-Vs) relationship with the marine clays of interest. The in-situ consolidation state was then evaluated by comparing the in-situ shear wave velocity data with the effective stress-shear wave velocity relationships obtained from laboratory experiments. The suggested methodology was applied and verified at three different sites in South Korea, i.e., a foreshore site in Incheon, a submarine deposit in Busan, and an estuary delta deposit in Busan. It is found that the shear wave-based experimental procedure presented in this paper can be effectively and reliably used to evaluate the consolidation state of marine clay deposits.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544778
|
oai_dc
|
Real-time unsaturated slope reliability assessmentconsidering variations in monitored matric suction
|
Real-time unsaturated slope reliability assessmentconsidering variations in monitored matric suction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jung Chan Choi(KAIST); 이승래(KAIST); Yunki Kim(Samsung C&T Corp.); Young Hoon Song(Hyundai Engineering & Construction Co., LTD.)"
] |
A reliability-based slope stability assessment method considering fluctuations in the monitored matric suction was proposed for real-time identification of slope risk. The assessment model was based on the limit equilibrium model for infinite slope failure. The first-order reliability method (FORM) was adopted to calculate the probability of slope failure, and results of the model were compared with Monte-Carlo Simulation (MCS) results to validate the accuracy and efficiency of the model. The analysis shows that a model based on Advanced First-Order Reliability Method (AFORM) generates results that are in relatively good agreement with those of the MCS, using a relatively small number of function calls. The contribution of random variables to the slope reliability index was also examined using sensitivity analysis. The results of sensitivity analysis indicate that the effective cohesion c' is a significant variable at low values of mean matric suction, whereasmatric suction (ua-uw) is the most influential factor at high mean suction values. Finally, the reliability indices of an unsaturated model soil slope, which was monitored by a wireless matric suction measurement system, were illustrated as 2D images using the suggested probabilistic model.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001544779
|
oai_dc
|
Evaluation of preconsolidation stress by shear wave velocity
|
Evaluation of preconsolidation stress by shear wave velocity
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"윤형구(Korea University); 이종섭(고려대학교); 이창호(전남대학교); 김현기(국민대학교)"
] |
The behaviors of saturated soils such as compressibility and permeability are distinguished by preconsolidation stress. Preconsolidation stress becomes an important design parameter in geotechnical structures. The goal of this study is to introduce a new method for the evaluation of preconsolidation stress based on the shear wave velocity at small strain, using Busan, Incheon, and Gwangyang clays in Korea. Standard consolidation tests are conducted by using an oedometer cell equipped with bender elements. The preconsolidation stresses estimated by shear wave velocity are compared with those evaluated by the Casagrande, constrained modulus, work, and logarithmic methods. The preconsolidation stresses estimated by the shear wave velocity produce very similar values to those evaluated by the Onitsuka method (one of the logarithmic methods), which yields an almost real preconsolidation stress. This study shows that the shear wave velocity method provides a reliable method for evaluating preconsolidation stress and can be used as a complementary method.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001518802
|
oai_dc
|
Fatigue laboratory tests toward the design of SMA portico-braces
|
Fatigue laboratory tests toward the design of SMA portico-braces
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"G. Carreras(ETSECCPB, UPC); F. Casciati(University of Pavia); S. Casciati(University of Catania); A. Isalgue(ETSECCPB, UPC); A. Marzi(University of Pavia); V. Torra(ETSECCPB, UPC)"
] |
A deeper understanding of the effectiveness of adopting devices mounting shape memory alloy (SMA) elements in applications targeted to the mitigation of vibrations is pursued via an experimental approach. During a seismic event, less than 1000 loading-unloading cycles of the alloy are required to mitigate the earthquake effects. However, the aging effects during the time of inactivity prior to the oscillations (several decades characterized by the yearly summer-winter temperature wave) should be considered in order to avoid and/or minimize them. In this paper, the results obtained by carrying out, in different laboratories, fatigue tests on SMA specimens are compared and discussed. Furthermore, the effects of seismic events on a steel structure, with and without SMA dampers, are numerically simulated using ANSYS. Under an earthquake excitation, the SMA devices halve the oscillation amplitudes and show re-centering properties. To confirm this result, an experimental campaign is conducted by actually installing the proposed devices on a physical model of the structure and by evaluating their performance under different excitations induced by an actuator.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001518795
|
oai_dc
|
Design and control of a proof-of-concept active jet engine intake using shape memory alloy actuators
|
Design and control of a proof-of-concept active jet engine intake using shape memory alloy actuators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gangbing Song(University of Houston); Ning Ma(University of Houston); Luyu Li(University of Houston); Nick Penney(Ohio Aerospace Institute (OAI)); Todd Barr(Jackson & Tull Aerospace Division); Ho-Jun Lee(NASA Glenn Research Center); Steve Arnold(NASA Glenn Research Center)"
] |
It has been shown in the literature that active adjustment of the intake area of a jet engine has potential to improve its fuel efficiency. This paper presents the design and control of a novel proof-of-concept active jet engine intake using Nickel-Titanium (Ni-Ti or Nitinol) shape memory alloy (SMA) wire actuators. The Nitinol SMA material is used in this research due to its advantages of high power-to-weight ratio and electrical resistive actuation. The Nitinol SMA material can be fabricated into a variety of shapes, such as strips, foils, rods and wires. In this paper, SMA wires are used due to its ability to generate a large strain: up to 6% for repeated operations. The proposed proof-of-concept engine intake employs overlapping leaves in a concentric configuration. Each leaf is mounted on a supporting bar than can rotate. The supporting bars are actuated by an SMA wire actuator in a ring configuration. Electrical resistive heating is used to actuate the SMA wire actuator and rotate the supporting bars. To enable feedback control, a laser range sensor is used to detect the movement of a leaf and therefore the radius of the intake area. Due to the hysteresis, an inherent nonlinear phenomenon associated with SMAs, a nonlinear robust controller is used to control the SMA actuators. The control design uses the sliding-mode approach and can compensate the nonlinearities associated with the SMA actuator. A proof-of-concept model is fabricated and its feedback control experiments show that the intake area can be precisely controlled using the SMA wire actuator and has the ability to reduce the area up to 25%. The experiments demonstrate the feasibility of engine intake area control using an SMA wire actuator under the proposed design.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001518800
|
oai_dc
|
Experimental evaluation of electrical conductivity of carbon fiber reinforced fly-ash based geopolymer
|
Experimental evaluation of electrical conductivity of carbon fiber reinforced fly-ash based geopolymer
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Saiprasad Vaidya(Louisiana Tech University); Erez N. Allouche(Louisiana Tech University)"
] |
Geopolymer concrete is finding a growing number of niche applications in the field of civil engineering due to its high compressive strength and strength gain rate, retainage of structural properties in elevated temperature environments, chemical stability in highly acidic conditions and environmental benefits. Combining the above mentioned characteristics with induced electrical conductivity, could enable geopolymer cement to serve as a smart and sustainable cementitious material suitable for health monitoring of civil structures. Carbon fibers were added to fresh geopolymer and OPC (ordinary Portland cement) mixes to enhance their electrical conductivities. AC-impedance spectroscopy analysis was performed on the specimens with fiber fraction ranging from 0.008 to 0.8 with respect to the weight of cementitious binder, to measure their electrical resistivity values and to determine the maximum beneficial fiber content required to attain electrical percolation. Experimental observations suggest that CFR-geopolymer cement exhibits superior performance to CFR-OPC in terms of conducting electrical current.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001518810
|
oai_dc
|
Output-only modal identification approach for time-unsynchronized signals from decentralized wireless sensor network for linear structural systems
|
Output-only modal identification approach for time-unsynchronized signals from decentralized wireless sensor network for linear structural systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박재형(부경대학교); 김정태(부경대학교); Jin-Hak Yi(Korea Ocean Research & Development Institute)"
] |
In this study, an output-only modal identification approach is proposed for decentralized wireless sensor nodes used for linear structural systems. The following approaches are implemented to achieve the objective. Firstly, an output-only modal identification method is selected for decentralized wireless sensor networks. Secondly, the effect of time-unsynchronization is assessed with respect to the accuracy of modal identification analysis. Time-unsynchronized signals are analytically examined to quantify uncertainties and their corresponding errors in modal identification results. Thirdly, a modified approach using complex mode shapes is proposed to reduce the unsynchronization-induced errors in modal identification. In the new way, complex mode shapes are extracted from unsynchronized signals to deal both with modal amplitudes and with phase angles. Finally, the feasibility of the proposed approach is evaluated from numerical and experimental tests by comparing with the performance of existing approach using real mode shapes.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001518799
|
oai_dc
|
Impedance-based health monitoring and mechanical testing of structures
|
Impedance-based health monitoring and mechanical testing of structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lizeth Vargas Palomino(Federal University of Uberlandia); Valder Steffen Jr.(Federal University of Uberlandia); Jose dos Reis Vieira de Moura Jr.(Federal University of Uberlandia); Karina Mayumi Tsuruta(Federal University of Uberlandia); Domingos Alves Rade(Federal University of Uberlandia)"
] |
The mechanical properties obtained from mechanical tests, such as tensile, buckling, impact and fatigue tests, are largely applied to several materials and are used today for preliminary studies for the investigation of a desired element in a structure and prediction of its behavior in use. This contribution focus on two widely used different tests: tensile and fatigue tests. Small PZT (Lead Titanate Zirconate) patches are bonded on the surface of test samples for impedance-based health monitoring purposes. Together with these two tests, the electromechanical impedance technique was performed by using aluminum test samples similar to those used in the aeronautical industry. The results obtained both from tensile and fatigue tests were compared with the impedance signatures. Finally, statistical meta-models were built to investigate the possibility of determining the state of the structure from the impedance signatures.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471518
|
oai_dc
|
Damage detection on two-dimensional structure based on active Lamb waves
|
Damage detection on two-dimensional structure based on active Lamb waves
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ge Peng(Nanjing University of Aeronautics and Astronautics); Shen Fang Yuan(Nanjing University of Aeronautics and Astronautics); Xin Xu(Nanjing University of Aeronautics and Astronautics)"
] |
This paper deals with damage detection using active Lamb waves. The wavelet transform and empirical mode decomposition methods are discussed for measuring the Lamb wave? arrival time of the group velocity. An experimental system to diagnose the damage in the composite plate is developed. A method to optimize this system is also given for practical applications of active Lamb waves, which involve optimal arrangement of the piezoelectric elements to produce single mode Lamb waves. In the paper, the single mode Lamb wave means that there exists no overlapping among different Lamb wave modes and the original Lamb wave signal with the boundary reflection signals. Based on this optimized PZT arrangement method, five damage localizations on different plates are completed and the results using wavelet transform and empirical mode decomposition methods are compared.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471516
|
oai_dc
|
Application of magnetoelastic stress sensors in large steel cables
|
Application of magnetoelastic stress sensors in large steel cables
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Guodun Wang(University of Illinois at Chicago); Ming L. Wang(University of Illinois at Chicago); Yang Zhao(University of Illinois at Chicago); Yong Chen(Zhejiang University); Bingnan Sun(Zhejiang University)"
] |
In this paper, the application of magnetoelasticity in static tension monitoring for large steel cables is discussed. Magnetoelastic (EM) stress sensors make contact-free tension monitoring possible for hanger cables and post-tensioned cables on suspension and cable-stayed bridges. By quantifying the correlation of magnetic relative permeability with tension and temperature, the EM sensors inspect the load levels in the steel cables. Cable tension monitoring on Qiangjiang (QJ) 4th Bridge demonstrates the reliability of the EM sensors.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471510
|
oai_dc
|
Covariance-driven wavelet technique for structural damage assessment
|
Covariance-driven wavelet technique for structural damage assessment
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Z. Sun(Tongji University); C.C. Chang(Hong Kong University of Science and Technology)"
] |
In this study, a wavelet-based covariance-driven system identification technique is proposed for damage assessment of structures under ambient excitation. Assuming the ambient excitation to be a white-noise process, the covariance computation is shown to be able to separate the effect of random excitation from the response measurement. Wavelet transform (WT) is then used to convert the covariance response in the time domain to the WT magnitude plot in the time-scale plane. The wavelet coefficients along the curves where energy concentrated are extracted and used to estimate the modal properties of the structure. These modal property estimations lead to the calculation of the stiffness matrix when either the spectral density of the random loading or the mass matrix is given. The predicted stiffness matrix hence provides a direct assessment on the possible location and severity of damage which results in stiffness alteration. To demonstrate the proposed wavelet-based damage assessment technique, a numerical example on a 3 degree-of-freedom (DOF) system and an experimental study on a three-story building model, which are all under a broad-band excitation, are presented. Both numerical and experimental results illustrate that the proposed technique can provide an accurate assessment on the damage location. It is however noted that the assessment of damage severity is not as accurate, which might be due to the errors associated with the mode shape estimations as well as the assumption of proportional damping adopted in the formulation.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471527
|
oai_dc
|
Smart sensors for monitoring crack growth under fatigue loading conditions
|
Smart sensors for monitoring crack growth under fatigue loading conditions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Victor Giurgiutiu(University of South Carolina); Buli Xu(University of South Carolina); Yuh Chao(University of South Carolina); Shu Liu(University of South Carolina); Rishi Gaddam(University of South Carolina)"
] |
Structural health monitoring results obtained with the electro-mechanical (E/M) impedance technique and Lamb wave transmission methods during fatigue crack propagation of an Arcan specimen instrumented with piezoelectric wafer active sensors (PWAS) are presented. The specimen was subjected in mixed-mode fatigue loading and a crack was propagated in stages. At each stage, an image of the crack and the location of the crack tip were recorded and the PWAS readings were taken. Hence, the crack-growth in the specimen could be correlated with the PWAS readings. The E/M impedance signature was recorded in the 100 - 500 kHz frequency range. The Lamb-wave transmission method used the pitch-catch approach with a 3-count sine tone burst of 474 kHz transmitted and received between various PWAS pairs. Fatigue loading was applied to initiate and propagate the crack damage of controlled magnitude. As damage progressed, the E/M impedance signatures and the waveforms received by receivers were recorded at predetermined intervals and compared. Data analysis indicated that both the E/M impedance signatures and the Lamb-wave transmission signatures are modified by the crack progression. Damage index values were observed to increase as the crack damage increases. These experiments demonstrated that the use of PWAS in conjunction with the E/M impedance and the Lamb-wave transmission is a potentially powerful tool for crack damage detection and monitoring in structural elements.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471512
|
oai_dc
|
HHT method for system identification and damage detection: an experimental study
|
HHT method for system identification and damage detection: an experimental study
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lily L. Zhou(Nanjing University of Aeronautics and Astronautics); Gang Yan(Nanjing University of Aeronautics and Astronautics)"
] |
Recently, the Hilbert-Huang transform (HHT) has gained considerable attention as a novel technique of signal processing, which shows promise for the system identification and damage detection of structures. This study investigates the effectiveness and accuracy of the HHT method for the system identification and damage detection of structures through a series of experiments. A multi-degree-of-freedom (MDOF) structural model has been constructed with modular members, and the columns of the model can be replaced or removed to simulate damages at different locations with different severities. The measured response data of the structure due to an impulse loading is first decomposed into modal responses using the empirical mode decomposition (EMD) approach with a band-pass filter technique. Then, the Hilbert transform is subsequently applied to each modal response to obtain the instantaneous amplitude and phase angle time histories. A linear least-square fit procedure is used to identify the natural frequencies and damping ratios from the instantaneous amplitude and phase angle for each modal response. When the responses at all degrees of freedom are measured, the mode shape and the physical mass, damping and stiffness matrices of the structure can be determined. Based on a comparison of the stiffness of each story unit prior to and after the damage, the damage locations and severities can be identified. Experimental results demonstrate that the HHT method yields quite accurate results for engineering applications, providing a promising tool for structural health monitoring.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471520
|
oai_dc
|
Sensor placement selection of SHM using tolerance domain and second order eigenvalue sensitivity
|
Sensor placement selection of SHM using tolerance domain and second order eigenvalue sensitivity
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. He(Harbin Institute of Technology); C.W. Zhang(Harbin Institute of Technology); J.P. Ou(Harbin Institute of Technology)"
] |
Monitoring large-scale civil engineering structures such as offshore platforms and high-large buildings requires a large number of sensors of different types. Innovative sensor data information technologies are very extremely important for data transmission, storage and retrieval of large volume sensor data generated from large sensor networks. How to obtain the optimal sensor set and placement is more and more concerned by researchers in vibration-based SHM. In this paper, a method of determining the sensor location which aims to extract the dynamic parameter effectively is presented. The method selects the number and place of sensor being installed on or in structure by through the tolerance domain statistical inference algorithm combined with second order sensitivity technology. The method proposal first finds and determines the sub-set sensors from the theoretic measure point derived from analytical model by the statistical tolerance domain procedure under the principle of modal effective independence. The second step is to judge whether the sorted out measured point set has sensitive to the dynamic change of structure by utilizing second order characteristic value sensitivity analysis. A 76-high-building benchmark mode and an offshore platform structure sensor optimal selection are demonstrated and result shows that the method is available and feasible.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001471509
|
oai_dc
|
Terra-Scope - a MEMS-based vertical seismic array
|
Terra-Scope - a MEMS-based vertical seismic array
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Steven D. Glaser(University of California); Min Chen(University of California); Thomas E. Oberheim(University of California)"
] |
The Terra-Scope system is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. They are expected to cost approximately $6000 each. An internal 16-bit, extremely low power MCU controls all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage. Each Pod measures 3-D acceleration, tilt, azimuth, temperature, and other parametric variables such as pore water pressure and pH. Each Pod communicates over a standard digital bus (RS-485) through a completely web-based GUI interface, and has a power consumption of less than 400 mW. Three-dimensional acceleration is measured by pure digital force-balance MEMS-based accelerometers. These accelerometers have a dynamic range of more than 115 dB and a frequency response from DC to 1000 Hz with a noise floor of less than 30 ngrms/Hz. Accelerations above 0.2 g are measured by a second set of MEMS- based accelerometers, giving a full 160 dB dynamic range. This paper describes the system design and the cooperative shared-time scheduler implemented for this project. Restraints accounted for include multiple data streams, integration of multiple free agents, interaction with the asynchronous world, and hardened time stamping of accelerometer data. The prototype of the device is currently undergoing evaluation. The first array will be installed in the spring of 2006.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364211
|
oai_dc
|
Optimal placement of piezoelectric curve beams in structural shape control
|
Optimal placement of piezoelectric curve beams in structural shape control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jian Wang(Dalian University of Technology); Guozhong Zhao(Dalian University of Technology); Hongwu Zhang(Dalian University of Technology)"
] |
Shape control of flexible structures using piezoelectric materials has attracted much attention due to its wide applications in controllable systems such as space and aeronautical engineering. The major work in the field is to find a best control voltage or an optimal placement of the piezoelectric actuators in order to actuate the structure shape as close as possible to the desired one. The current research focus on the investigation of static shape control of intelligent shells using spatially distributed piezoelectric curve beam
actuators. The finite element formulation of the piezoelectric model is briefly described. The piezoelectric curve beam element is then integrated into a collocated host shell element by using nodal displacement constraint equations. The linear least square method (LLSM) is employed to get the optimum voltage distributions in the control system so that the desired structure shape can be well matched. Furthermore, to find the optimal placement of the piezoelectric curve beam actuators, a genetic algorithm (GA) is introduced in the computation model as well as the consideration of the different objective functions. Numerical results are given to demonstrate the validity of the theoretical model and numerical algorithm developed.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364212
|
oai_dc
|
Fuzzy-sliding mode control of a full car semi-active suspension systems with MR dampers
|
Fuzzy-sliding mode control of a full car semi-active suspension systems with MR dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. Zheng(Chongqing University); Y. N. Li(Chongqing University); A. Baz(University of Maryland)"
] |
A fuzzy-sliding mode controller is presented to control the dynamics of semi-active suspension systems of vehicles using magneto-rheological (MR) fluid dampers. A full car model is used to design and evaluate the performance of the proposed semi-active controlled suspension system. Four mixed mode MR
dampers are designed, manufactured, and integrated with four independent sliding mode controllers. The siding mode controller is designed to decrease the energy consumption and maintain robustness. In order to overcome the
chattering of the sliding mode controllers, a fuzzy logic control strategy is merged into the sliding mode controller.
The proposed fuzzy-sliding mode controller is designed and fabricated. The performance of the semi-active suspensions is evaluated in both the time and frequency domains. The obtained results demonstrate that the proposed fuzzy-sliding mode controller can effectively suppress the vibration of vehicles and improve their ride comfort and handling stability. Furthermore, it is shown that the “chattering” of the sliding mode controller is smoothed when it is integrated with a fuzzy logic control strategy. Although the cost function of the fuzzy-sliding mode control is a slightly higher than that of a classical LQR controller, the control effectiveness and robustness are enhanced considerably.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364204
|
oai_dc
|
Sliding mode control for structures based on the frequency content of the earthquake loading
|
Sliding mode control for structures based on the frequency content of the earthquake loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nikos G. Pnevmatikos(National Technical University of Athens); Charis J. Gantes(National Technical University of Athens)"
] |
A control algorithm for seismic protection of building structures based on the theory of variable structural control or sliding mode control is presented. The paper focus in the design of sliding surface. A method for determining the sliding surface by pole assignment algorithm where the poles of the system in the sliding surface are obtained on-line, based on the frequency content of the incoming earthquake signal applied to the structure, is proposed. The proposed algorithm consists of the following steps: (i) On-line FFT process is applied to the incoming part of the signal and its frequency content is recognized. (ii) A transformation of the frequency content to the complex plane is performed and the desired location of poles of the controlled structure on the sliding surface is estimated. (iii) Based on the estimated poles the sliding surface is obtained. (iv) Then, the control force which will drive the response trajectory into the estimated sliding surface and force it to stay there all the subsequent time is obtained using Lyapunov stability theory. The above steps are repeated continuously for the entire duration of the incoming earthquake. The potential applications and the effectiveness of the improved control algorithm are demonstrated by numerical examples. The simulation results indicate that the response of a structure is reduced significantly compared to the response of the uncontrolled structure, while the required control demand is achievable.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364215
|
oai_dc
|
Damage detection for truss or frame structures using an axial strain flexibility
|
Damage detection for truss or frame structures using an axial strain flexibility
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Guirong Yan(Harbin Institute of Technology); Zhongdong Duan(Harbin Institute of Technology); Jinping Ou(Harbin Institute of Technology)"
] |
Damage detection using structural classical deflection flexibility has received considerable attention due to the unique features of the flexibility in the last two decades. However, for relatively complex structures, most methods based on classical deflection flexibility fail to locate damage sites to the exact members. In this study, for structures whose members are dominated by axial forces, such as truss structures, a more feasible flexibility for damage detection is proposed, which is called the Axial Strain (AS) flexibility. It is synthesized from measured modal frequencies and axial strain mode shapes which are expressed in terms of translational mode shapes. A damage indicator based on AS flexibility is proposed. In addition, how to integrate the AS flexibility into the Damage Location Vector (DLV) approach (Bernal and Gunes 2004) to improve its performance of damage localization is presented. The methods based on AS flexbility localize multiple damages to the exact
members and they are suitable for the cases where the baseline data of the intact structure is not available. The proposed methods are demonstrated by numerical simulations of a 14-bay planar truss and a five-story steel frame
and experiments on a five-story steel frame.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364208
|
oai_dc
|
Health Monitoring System (HMS) for structural assessment
|
Health Monitoring System (HMS) for structural assessment
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"José Campos e Matos(University of Porto); Oscar Garcia(University of Girona); António Abel Henriques(University of Porto); Josep Vehí(University of Girona); Joan Ramon Casas(Technical University of Catalonia)"
] |
As in any engineering application, the problem of structural assessment should face the different uncertainties present in real world. The main source of uncertainty in Health Monitoring System (HMS) applications are those related to the sensor accuracy, the theoretical models and the variability in structural parameters and applied loads. In present work, two methodologies have been developed to deal with these uncertainties in order to adopt reliable decisions related to the presence of damage. A simple example, a steel beam analysis, is considered in order to establish a liable comparison between them. Also, such methodologies are used with a developed structural assessment algorithm that consists in a direct and consistent comparison between sensor data and numerical model results, both affected by uncertainty. Such algorithm is applied to a simple concrete laboratory beam, tested till rupture, to show it feasibility and operational process. From these applications several conclusions are derived with a high value, regarding the final objective of the work, which is the implementation of this algorithm within a HMS, developed and applied into a prototype structure.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364214
|
oai_dc
|
Microcontroller based split mass resonant sensor for absolute and differential sensing
|
Microcontroller based split mass resonant sensor for absolute and differential sensing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"G. Uma(National Institute of Technology, India); M. Umapathy(National Institute of Technology, India); K. Suneel Kumar(National Institute of Technology, India); K. Suresh(National Institute of Technology); A. Maria Josephine(National Institute of Technology, India)"
] |
Two degrees of freedom resonant systems are employed to improve the resonant property of resonant sensor, as compared to a single degree of freedom resonant system. This paper presents design, development and
testing of two degrees of freedom resonant sensor. To measure absolute mass, cantilever shaped two different masses (smaller/absorber mass and bigger/drive mass) with identical resonant frequency are mechanically linked
to form 2 - Degree-of-Freedom (DOF) resonator which exhibits higher amplitude of displacement at the smaller mass. The same concept is extended for measuring differential quantity, by having two bigger mass and one
smaller mass. The main features of this work are the 3 - DOF resonator for differential detection and the microcontroller based closed loop electronics for resonant sensor with piezoelectric sensing and excitation. The advantage of using microcontroller is that the method can be easily extended for any range of measurand.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415966
|
oai_dc
|
Electromagnetic actuator design for the control of light structures
|
Electromagnetic actuator design for the control of light structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Johan Der Hagopian(Institut National des Sciences Appliquées de Lyon); Jarir Mahfoud(Institut National des Sciences Appliquées de Lyon)"
] |
An ElectroMagnetic Actuator (EMA) is designed and assessed numerically and experimentally. The EMA has the advantage to be without contact with the structure so it could be applied to light and small mechanism. Nevertheless, the open-loop instability and the nonlinear dynamic behavior with respect to the excitation frequency could limit its application field. The EMA is designed and dimensioned as a function of the experimental structure to be controlled. An inverse model of the EMA is proposed in order to implement a linear action block for the used frequency range. The control strategy is a fuzzy controller with displacements and velocities as inputs. A fuzzy controller of Takagi-Sugeno type is used. The air gap is estimated by using a modal approximation of the displacements issued from all measurements. Several configurations of control are assessed by using numerical simulations. The block diagram used for numerical simulations is implemented under Dspace?environment. The implemented controller was tested experimentally in the context of impact perturbations. The results obtained show the effectiveness of the developed procedures and the robustness of the implemented control.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415973
|
oai_dc
|
Structural health monitoring of the Manitoba Golden Boy
|
Structural health monitoring of the Manitoba Golden Boy
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bogdan A. Bogdanovic(Crosier Kilgour Partners. Ltd.); Ashutosh Bagchi(Concordia University); Aftab A. Mufti(University of Manitoba)"
] |
토목공학
| null |
kci_detailed_000093.xml
|
||||
ART001415968
|
oai_dc
|
Smart pattern recognition of structural systems
|
Smart pattern recognition of structural systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Maguid H. M. Hassan(The British University in Egypt)"
] |
Structural Control relies, with a great deal, on the ability of the control algorithm to identify the current state of the system, at any given point in time. When such algorithms are designed to perform in a smart manner, several smart technologies/devices are called upon to perform tasks that involve pattern recognition and control. Smart pattern recognition is proposed to replace/enhance traditional state identification techniques, which require the extensive manipulation of intricate mathematical equations. Smart pattern recognition techniques attempt to emulate the behavior of the human brain when performing abstract pattern identification. Since these techniques are largely heuristic in nature, it is reasonable to ensure their reliability under real life situations. In this paper, a neural network pattern recognition scheme is explored. The pattern identification of three structural systems is considered. The first is a single bay three-story frame. Both the second and the third models are variations on benchmark problems, previously published for control strategy evaluation purposes. A Neural Network was developed and trained to identify the deformed shape of structural systems under earthquake excitation. The network was trained, for each individual model system, then tested under the effect of a different set of earthquake records. The proposed smart pattern identification scheme is considered an integral component of a Smart Structural System. The Reliability assessment of such component represents an important stage in the evaluation of an overall reliability measure of Smart Structural Systems. Several studies are currently underway aiming at the identification of a reliability measure for such smart pattern recognition technique.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415962
|
oai_dc
|
Design of a smart MEMS accelerometer using nonlinear control principles
|
Design of a smart MEMS accelerometer using nonlinear control principles
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Faezeh Arab Hassani(University of Tehran); Amir Farrokh Payam(University of Tehran); Morteza Fathipour(University of Tehran)"
] |
This paper presents a novel smart MEMS accelerometer which employs a hybrid control algorithm and an estimator. This scheme is realized by adding a sliding-mode controller to a conventional PID closed loop system to achieve higher stability and higher dynamic range and to prevent pull-in phenomena by preventing finger displacement from passing a maximum preset value as well as adding an adaptive nonlinear observer to a conventional PID closed loop system. This estimator is used for online estimation of the parameter variations for MEMS accelerometers and gives the capability of self testing to the system. The analysis of convergence and resolution show that while the proposed control scheme satisfies these criteria it also keeps resolution performance better than what is normally obtained in conventional PID controllers. The performance of the proposed hybrid controller investigated here is validated by computer simulation.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415964
|
oai_dc
|
Statistical approach to a SHM benchmark problem
|
Statistical approach to a SHM benchmark problem
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sara Casciati(University of Catania)"
] |
The approach to damage detection and localization adopted in this paper is based on a statistical comparison of models built from the response time histories collected at different stages during the structure lifetime. Some of these time histories are known to have been recorded when the structural system was undamaged. The consistency of the models associated to two different stages, both undamaged, is first recognized. By contrast, the method detects the discrepancies between the models from measurements collected for a damaged situation and for the undamaged reference situation. The damage detection and localization is pursued by a comparison of the SSE (sum of the squared errors) histograms. The validity of the proposed approach is tested by applying it to the analytical benchmark problem developed by the ASCE Task Group on Structural Health Monitoring (SHM). In the paper, the results of the benchmark studies are presented and the performance of the method is discussed.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415971
|
oai_dc
|
Experimental studies on the fatigue life of shape memory alloy bars
|
Experimental studies on the fatigue life of shape memory alloy bars
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sara Casciati(University of Catania); Alessandro Marzi(University of Pavia)"
] |
The potential offered by the thermo-mechanical properties of shape memory alloys (SMA) in structural engineering applications has been the topic of many research studies during the last two decades. The main issues concern the long-term predictability of the material behaviour and the fatigue lifetime of the macro structural elements (as different from the one of wire segments). The laboratory tests reported in this paper are carried out on bar specimens and they were planned in order to pursue two objectives. First, the creep phenomenon is investigated for two different alloys, a classical Ni-Ti alloy and a Cu-based alloy. The attention is then focused on the Cu-based alloy only and its fatigue characteristics at given temperatures are investigated. Stress and thermal cycles are alternated to detect any path dependency.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001415970
|
oai_dc
|
Small scale experimental testing to verify the effectiveness of the base isolation and tuned mass dampers combined control strategy
|
Small scale experimental testing to verify the effectiveness of the base isolation and tuned mass dampers combined control strategy
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Luigi Petti(University of Salerno); Giovanni Giannattasio(University of Salerno); Massimiliano De Iuliis(University of Salerno); Bruno Palazzo(University of Salerno)"
] |
This paper presents the most significant results obtained within a broad-ranging experimental program aiming to evaluate both the effectiveness and the robustness of a Base Isolation (BIS) and a Tuned Mass Damper (TMD) combined control strategy (BI & TMD). Following a brief description of the experimental model set-up and the adopted kinematic scaling technique, this paper describes the identification procedures carried out to characterize the system뭩 model. The dynamic response of a small-scale model to recorded earthquake excitations, which has been scaled by using the Buckingham pi-theorem, are later presented and discussed. Finally, the effectiveness and robustness of the combined control strategy is evaluated by comparing the model뭩 dynamic response. In particular, reduction in relative displacements and absolute accelerations due to the application of different mass damping systems is investigated.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364184
|
oai_dc
|
Middleware services for structural health monitoring using smart sensors
|
Middleware services for structural health monitoring using smart sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. Nagayama(University of Tokyo); B. F. Spencer, Jr.(University of Illinois); K. A. Mechitov(University of Illinois); G. A. Agha(University of Illinois)"
] |
Smart sensors densely distributed over structures can use their computational and wireless communication capabilities to provide rich information for structural health monitoring (SHM). Though smart sensor technology has seen substantial advances during recent years, implementation of smart sensors on full-scale structures has been limited. Hardware resources available on smart sensors restrict data acquisition capabilities;
intrinsic to these wireless systems are packet loss, data synchronization errors, and relatively slow communication speeds. This paper addresses these issues under the hardware limitation by developing corresponding middleware services. The reliable communication service requires only a few acknowledgement packets to compensate for packet loss. The synchronized sensing service employs a resampling approach leaving the need for strict control of sensing timing. The data aggregation service makes use of application specific knowledge and distributed computing to suppress data transfer requirements. These middleware services are implemented on the Imote2 smart sensor platform, and their efficacy demonstrated experimentally.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364188
|
oai_dc
|
Model-based and wavelet-based fault detection and diagnosis for biomedical and manufacturing applications: Leading Towards Better Quality of Life
|
Model-based and wavelet-based fault detection and diagnosis for biomedical and manufacturing applications: Leading Towards Better Quality of Life
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Imin Kao(SUNY); Xiaolin Li(SUNY); Chia-Hung Dylan Tsai(SUNY)"
] |
In this paper, the analytical fault detection and diagnosis (FDD) is presented using model-based and signal-based methodology with wavelet analysis on signals obtained from sensors and sensor networks. In the model-based FDD, we present the modeling of contact interface found in soft materials, including the biomedical contacts. Fingerprint analysis and signal-based FDD are also presented with an experimental framework consisting of a mechanical pneumatic system typically found in manufacturing automation. This diagnosis system focuses on the signal-based approach which employs multi-resolution wavelet decomposition of various sensor signals such as pressure, flow rate, etc., to determine leak configuration. Pattern recognition technique and analytical vectorized maps are developed to diagnose an unknown leakage based on the established FDD information using
the affine mapping. Experimental studies and analysis are presented to illustrate the FDD methodology. Both model-based and wavelet-based FDD applied in contact interface and manufacturing automation have implication
towards better quality of life by applying theory and practice to understand how effective diagnosis can be made using intelligent FDD. As an illustration, a model-based contact surface technology an benefit the diabetes with the
detection of abnormal contact patterns that may result in ulceration if not detected and treated in time, thus, improving the quality of life of the patients. Ultimately, effective diagnosis using FDD with wavelet analysis, whether it is employed in biomedical applications or manufacturing automation, can have impacts on improving our quality of life.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364187
|
oai_dc
|
Bio-inspired self powered nervous system for civil structures
|
Bio-inspired self powered nervous system for civil structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rahmat A. Shoureshi(University of Denver); Sun W. Lim(University of Denver)"
] |
Globally, civil infrastructures are deteriorating at an alarming rate caused by overuse, overloading, aging, damage or failure due to natural or man-made hazards. With such a vast network of deteriorating infrastructure,
there is a growing interest in continuous monitoring technologies. In order to provide a true distributed sensor and control system for civil structures, we are developing a Structural Nervous System that mimics key attributes
of a human nervous system. This nervous system is made up of building blocks that are designed based on mechanoreceptors as a fundamentally new approach for the development of a structural health monitoring and
diagnostic system that utilizes the recently developed piezo-fibers capable of sensing and actuation. In particular, our research has been focused on producing a sensory nervous system for civil structures by using piezo-fibers as sensory receptors, nerve fibers, neuronal pools, and spinocervical tract to the nodal and central processing units.
This paper presents up to date results of our research, including the design and analysis of the structural nervous system.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364201
|
oai_dc
|
A remotely controllable structural health monitoring framework for bridges using 3.5 generation mobile telecommunication technology
|
A remotely controllable structural health monitoring framework for bridges using 3.5 generation mobile telecommunication technology
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"구기영(KAIST); Jun-Young Hong(KAIST); 박승희(성균관대학교); 이종재(세종대학교); 윤정방(한국과학기술원)"
] |
A framework for structural health monitoring (SHM) systems is presented utilizing a recent 3.5 generation mobile telecommunication technology, HSDPA (High Speed Downlink Packet Access). It may be effectively applied to monitoring bridges, cut-slopes, and other facilities located in rural areas where the conventional Internet service is not readily available, since HSDPA is currently commercialized in 86 countries to make the Internet access possible in anywhere the mobile phone service is available. The proposed SHM framework is also incorporating remote desktop software to have remote control/operation of the SHM systems.
The feasibility of the proposed framework has been demonstrated by field tests on a highway bridge in operation.
One can expect that fast advances in the mobile telecommunication technology will further enhance the performance of the SHM network using the proposed framework for bridges and other facilities located in remote
areas without the conventional wired Internet service.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364189
|
oai_dc
|
The needs for advanced sensor technologies in risk assessment of civil infrastructures
|
The needs for advanced sensor technologies in risk assessment of civil infrastructures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yozo Fujino(The University of Tokyo); Dionysius M. Siringoringo(The University of Tokyo); Masato Abe(BMC Corporation)"
] |
Civil infrastructures are always subjected to various types of hazard and deterioration. These conditions require systematic efforts to assess the exposure and vulnerability of infrastructure, as well as producing strategic countermeasures to reduce the risks. This paper describes the needs for and concept of advanced sensor technologies for risk assessment of civil infrastructure in Japan. Backgrounds of the infrastructure problems such as natural disasters, difficult environment, limited resource for maintenance, and
increasing requirement for safety are discussed. The paper presents a concept of risk assessment, which is defined as a combination of hazard and structural vulnerability assessment. An overview of current practices
and research activities toward implementing the concept is presented. This includes implementation of structural health monitoring (SHM) systems for environment and natural disaster prevention, improvement of stock management, and prevention of structural failure.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001440573
|
oai_dc
|
Application of principal component analysis and wavelet transform to fatigue crack detection in waveguides
|
Application of principal component analysis and wavelet transform to fatigue crack detection in waveguides
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marcello Cammarata(University of Pittsburgh); Piervincenzo Rizzo(University of Pittsburgh); Debaditya Dutta(Carnegie Mellon University); 손훈(KAIST, Korea)"
] |
Ultrasonic Guided Waves (UGWs) are a useful tool in structural health monitoring (SHM) applications that can benefit from built-in transduction, moderately large inspection ranges and high sensitivity to small flaws. This paper describes a SHM method based on UGWs, discrete wavelet transform (DWT), and principal component analysis (PCA) able to detect and quantify the onset and propagation of fatigue cracks in structural waveguides. The method combines the advantages of guided wave signals processed through the DWT with the outcomes of selecting defect-sensitive features to perform a multivariate diagnosis of damage. This diagnosis is based on the PCA. The framework presented in this paper is applied to the detection of fatigue cracks in a steel beam. The probing hardware consists of a PXI platform that controls the generation and measurement of the ultrasonic signals by means of piezoelectric transducers made of Lead Zirconate Titanate. Although the approach is demonstrated in a beam test, it is argued that the proposed method is general and applicable to any structure that can sustain the propagation of UGWs.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001442288
|
oai_dc
|
Early warning of hazard for pipelines by acoustic recognition using principal component analysis and one-class support vector machines
|
Early warning of hazard for pipelines by acoustic recognition using principal component analysis and one-class support vector machines
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chunfeng Wan(Southeast University); Akira Mita(Keio University)"
] |
This paper proposes a method for early warning of hazard for pipelines. Many pipelines transport dangerous contents so that any damage incurred might lead to catastrophic consequences. However, most of these damages are usually a result of surrounding third-party activities, mainly the constructions. In order to prevent accidents and disasters, detection of potential hazards from third-party activities is indispensable. This paper focuses on recognizing the running of construction machines because they indicate the activity of the constructions. Acoustic information is applied for the recognition and a novel pipeline monitoring approach is proposed. Principal Component Analysis (PCA) is applied. The obtained Eigenvalues are regarded as the special signature and thus used for building feature vectors. One-class Support Vector Machine (SVM) is used for the classifier. The denoising ability of PCA can make it robust to noise interference, while the powerful classifying ability of SVM can provide good recognition results. Some related issues such as standardization are also studied and discussed. On-site experiments are conducted and results prove the effectiveness of the proposed early warning method. Thus the possible hazards can be prevented and the integrity of pipelines can be ensured.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001441350
|
oai_dc
|
Finite element model updating of Kömürhan highway bridge based on experimental measurements
|
Finite element model updating of Kömürhan highway bridge based on experimental measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Alemdar Bayraktar(Karadeniz Technical University); Ahmet Can Altunisik(Karadeniz Technical University); Baris Sevim(Karadeniz Technical University); Temel Türker(Karadeniz Technical University)"
] |
The updated finite element model of Kömürhan Highway Bridge on the Flrat River located on the 51st km of Elazl-Malatya highway is obtained by using analytical and experimental results. The 2D and 3D finite element model of the bridge is created by using SAP2000 structural analyses software, and the dynamic characteristics of the bridge are determined analytically. The experimental measurements are carried out by Operational Modal Analysis Method under traffic induced vibrations and the dynamic characteristics are obtained experimentally. The vibration data are gathered from the both box girder and the deck of the bridge, separately. Due to the expansion joint in the middle of the bridge, special measurement points are selected when experimental test setups constitute. Measurement duration, frequency span and effective mode number are determined by considering similar studies in literature. The Peak Picking method in the frequency domain is used in the modal identification. At the end of the study, analytical and experimental dynamic characteristic are compared with each other and the finite element model of the bridge is updated by changing some uncertain parameters such as material properties and boundary conditions. Maximum differences between the natural frequencies are reduced from 10% to 2%, and a good agreement is found between natural frequencies and mode shapes after model updating.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001440595
|
oai_dc
|
Probabilistic distribution of displacement response of frictionally damped structures excited by seismic loads
|
Probabilistic distribution of displacement response of frictionally damped structures excited by seismic loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이상현(단국대학교); K.J. Youn(Dankook University); 민경원(단국대학교); 박지훈(인천대학교)"
] |
Accurate peak response estimation of a seismically excited structure with frictional damping system (FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated the peak response of the structure with FDS by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In case that earthquake excitation is defined probabilistically, corresponding response of the structure with FDS becomes to have probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake excitation generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Coefficients of the proposed PDF are obtained by regression of the statistical distribution of the time history responses. Finally, the correlation between the resulting PDFs and statistical response distribution is investigated.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001442263
|
oai_dc
|
Image recognition technology in rotating machinery fault diagnosis based on artificial immune
|
Image recognition technology in rotating machinery fault diagnosis based on artificial immune
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhu Dachang(Jiangxi University of Science and Technology); Feng Yanping(Jiangxi University of Science and Technology); Chen Qiang(Jiangxi University of Science and Technology); Cai Jinbao(Jiangxi University of Science and Technology)"
] |
By using image recognition technology, this paper presents a new fault diagnosis method for rotating machinery with artificial immune algorithm. This method focuses on the vibration state parameter image. The main contribution of this paper is as follows: firstly, 3-D spectrum is created with raw vibrating signals. Secondly, feature information in the state parameter image of rotating machinery is extracted by using Wavelet Packet transformation. Finally, artificial immune algorithm is adopted to diagnose rotating machinery fault. On the modeling of 600MW turbine experimental bench, rotor normal rate, fault of unbalance, misalignment and bearing pedestal looseness are being examined. It demonstrated from the diagnosis example of rotating machinery that the proposed method can improve the accuracy rate and diagnosis system robust quality effectively.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437732
|
oai_dc
|
Assessment of London underground tube tunnels - investigation, monitoring and analysis
|
Assessment of London underground tube tunnels - investigation, monitoring and analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Peter Wright(Tube Lines)"
] |
Tube Lines has carried out a knowledge and investigation programme on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a wish-list. Assessment reports have now been produced for all assets forming Tube Lines deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437735
|
oai_dc
|
Wireless structural health monitoring of bridges: present and future
|
Wireless structural health monitoring of bridges: present and future
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Neil A. Hoult(Queen's University); Paul R.A. Fidler(University of Cambridge); Peter G. Hill(Humber Bridge Board); Campbell R. Middleton(University of Cambridge)"
] |
Internationally the load carrying capacity of bridges is decreasing due to material deterioration while at the same time increasing live loads mean that they are often exposed to stresses for which they were not designed. However there are limited resources available to ensure that these bridges are fit for purpose, meaning that new approaches to bridge maintenance are required that optimize both their service lives as well as maintenance costs. Wireless sensor networks (WSNs) provide a tool that could support such an optimized maintenance program. In many situations WSNs have advantages over conventional wired monitoring systems in terms of installation time and cost. In order to evaluate the potential of these systems two WSNs were installed starting in July 2007 on the Humber Bridge and on a nearby approach bridge. As part of a corrosion prevention strategy, a relative humidity and temperature monitoring system was installed in the north anchorage chambers of the main suspension bridge where the main cables of the bridge are anchored into the foundation. This system allows the Bridgemaster to check whether the maximum relative humidity threshold, above which corrosion of the steel wires might occur, is not crossed. A second WSN which monitors aspects of deterioration on a reinforced concrete bridge located on the approach to the main suspension bridge was also installed. Though both systems have provided useful data to the owners, there are still challenges that must be overcome in terms of monitoring corrosion of steel, measuring live loading and data management before WSNs can become an effective tool for bridge managers.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437737
|
oai_dc
|
Sensor enriched infrastructure system
|
Sensor enriched infrastructure system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ming L. Wang(Northeastern University); 임진석(Intelligent Instrument System)"
] |
Civil infrastructure, in both its construction and maintenance, represents the largest societal investment in this country, outside of the health care industry. Despite being the lifeline of US commerce, civil infrastructure has scarcely benefited from the latest sensor technological advances. Our future should focus on harnessing these technologies to enhance the robustness, longevity and economic viability of this vast, societal investment, in light of inherent uncertainties and their exposure to service and even extreme loadings. One of the principal means of insuring the robustness and longevity of infrastructure is to strategically deploy smart sensors in them. Therefore, the objective is to develop novel, durable, smart sensors that are especially applicable to major infrastructure and the facilities to validate their reliability and long-term functionality. In some cases, this implies the development of new sensing elements themselves, while in other cases involves innovative packaging and use of existing sensor technologies. In either case, a parallel focus will be the integration and networking of these smart sensing elements for reliable data acquisition, transmission, and fusion, within a decision-making framework targeting efficient management and maintenance of infrastructure systems. In this paper, prudent and viable sensor and health monitoring technologies have been developed and used in several large structural systems. Discussion will also include several practical bridge health monitoring applications including their design, construction, and operation of the systems.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437736
|
oai_dc
|
A sensor for confident identification of structural damage in reinforced concrete buildings
|
A sensor for confident identification of structural damage in reinforced concrete buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mete A. Sözen(Purdue University); Santiago Pujol(Purdue University)"
] |
A specific type of structural damage that would benefit from remote sensing is discussed and a solution is suggested.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437734
|
oai_dc
|
Wireless sensor networks for long-term structural health monitoring
|
Wireless sensor networks for long-term structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jonas Meyer(Swiss Federal Laboratories for Materials Testing and Research); Reinhard Bischoff(Swiss Federal Laboratories for Materials Testing and Research); Glauco Feltrin(Swiss Federal Laboratories for Materials Testing and Research); Masoud Motavalli(Swiss Federal Laboratories for Materials Testing and Research)"
] |
In the last decade, wireless sensor networks have emerged as a promising technology that could accelerate progress in the field of structural monitoring. The main advantages of wireless sensor networks compared to conventional monitoring technologies are fast deployment, small interference with the surroundings, self-organization, flexibility and scalability. These features could enable mass application of monitoring systems, even on smaller structures. However, since wireless sensor network nodes are battery powered and data communication is the most energy consuming task, transferring all the acquired raw data through the network would dramatically limit system lifetime. Hence, data reduction has to be achieved at the node level in order to meet the system lifetime requirements of real life applications. The objective of this paper is to discuss some general aspects of data processing and management in monitoring systems based on wireless sensor networks, to present a prototype monitoring system for civil engineering structures, and to illustrate long-term field test results.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437708
|
oai_dc
|
Structural monitoring of wind turbines using wireless sensor networks
|
Structural monitoring of wind turbines using wireless sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Andrew Swartz(Michigan Technological University); Jerome P. Lynch(University of Michigan); Stephan Zerbst(Leibniz University of Hanover); Bert Sweetman(Texas A&M Galveston); Raimund Rolfes(Leibniz University of Hanover)"
] |
Monitoring and economical design of alternative energy generators such as wind turbines is becoming increasingly critical; however acquisition of the dynamic output data can be a time-consuming and costly process. In recent years, low-cost wireless sensors have emerged as an enabling technology for structural monitoring applications. In this study, wireless sensor networks are installed in three operational turbines in order to demonstrate their efficacy in this unique operational environment. The objectives of the first installation are to verify that vibrational (acceleration) data can be collected and transmitted within a turbine tower and that it is comparable to data collected using a traditional tethered system. In the second instrumentation, the wireless network includes strain gauges at the base of the structure. Also, data is collected regarding the performance of the wireless communication channels within the tower. In both turbines, collected wireless sensor data is used for off-line, output-only modal analysis of the ambiently (wind) excited turbine towers. The final installation is on a turbine with embedded braking capabilities within the nacelle to generate an impulse-like load at the top of the tower. This ability to apply such a load improves the modal analysis results obtained in cases where ambient excitation fails to be sufficiently broad-band or white. The improved loading allows for computation of true mode shapes, a necessary precursor to many conditional monitoring techniques.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437711
|
oai_dc
|
Initial development of wireless acoustic emission sensor Motes for civil infrastructure state monitoring
|
Initial development of wireless acoustic emission sensor Motes for civil infrastructure state monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Christian U. Grosse(Technische Universitat Munchen); Steven D. Glaser(University of California); Markus Kruger(Materialprufungsanstalt Universitat)"
] |
The structural state of a bridge is currently examined by visual inspection or by wired sensor techniques, which are relatively expensive, vulnerable to inclement conditions, and time consuming to undertake. In contrast, wireless sensor networks are easy to deploy and flexible in application so that the network can adjust to the individual structure. Different sensing techniques have been used with such networks, but the acoustic emission technique has rarely been utilized. With the use of acoustic emission (AE) techniques it is possible to detect internal structural damage, from cracks propagating during the routine use of a structure, e.g. breakage of prestressing wires. To date, AE data analysis techniques are not appropriate for the requirements of a wireless network due to the very exact time synchronization needed between multiple sensors, and power consumption issues. To unleash the power of the acoustic emission technique on large, extended structures, recording and local analysis techniques need better algorithms to handle and reduce the immense amount of data generated. Preliminary results from utilizing a new concept called Acoustic Emission Array Processing to locally reduce data to information are presented. Results show that the azimuthal location of a seismic source can be successfully identified, using an array of six to eight poor-quality AE sensors arranged in a circular array approximately 200 mm in diameter. AE beamforming only requires very fine time synchronization of the sensors within a single array, relative timing between sensors of 1 ms can easily be performed by a single Mote servicing the array. The method concentrates the essence of six to eight extended waveforms into a single value to be sent through the wireless network, resulting in power savings by avoiding extended radio transmission.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437715
|
oai_dc
|
Ionic Polymer Transducers in sensing: the streaming potential hypothesis
|
Ionic Polymer Transducers in sensing: the streaming potential hypothesis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lisa Mauck Weiland(University of Pittsburgh); Barbar Akle(Lebanese American University)"
] |
Accurate sensing of mechanical strains in civil structures is critical for optimizing structure reliability and lifetime. For instance, combined with intelligent control systems, electromechanical sensor output feedback has the potential to be employed for nondestructive damage evaluation. Application of Ionic Polymer Transducers (IPTs) represents a relatively new sensing approach with more than an order of magnitude higher sensitivity than traditional piezoelectric sensors. The primary reason this sensor has not been widely used to date is an inadequate understanding of the physics responsible for IPT sensing. This paper presents models and experiments defending the hypothesis of a streaming potential sensing mechanism.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437723
|
oai_dc
|
Fabrication and packaging techniques for the application of MEMS strain sensors to wireless crack monitoring in ageing civil infrastructures
|
Fabrication and packaging techniques for the application of MEMS strain sensors to wireless crack monitoring in ageing civil infrastructures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Matteo Ferri(National Research Council of Italy); Fulvio Mancarella(National Research Council of Italy); Ashwin Seshia(University of Cambridge); James Ransley(University of Cambridge); Kenichi Soga(University of Cambridge); Jan Zalesky(Czech Technical University in Prague); Alberto Roncaglia(National Research Council of Italy)"
] |
We report on the development of a new technology for the fabrication of Micro-Electro-Mechanical-System (MEMS) strain sensors to realize a novel type of crackmeter for health monitoring of ageing civil infrastructures. The fabrication of micromachined silicon MEMS sensors based on a Silicon On Insulator (SOI) technology, designed according to a Double Ended Tuning Fork (DETF) geometry is presented, using a novel process which includes a gap narrowing procedure suitable to fabricate sensors with low motional resistance. In order to employ these sensors for crack monitoring, techniques suited for bonding the MEMS sensors on a steel surface ensuring good strain transfer from steel to silicon and a packaging technique for the bonded sensors are proposed, conceived for realizing a low-power crackmeter for ageing infrastructure monitoring. Moreover, the design of a possible crackmeter geometry suited for detection of crack contraction and expansion with a resolution of 10 and very low power consumption requirements (potentially suitable for wireless operation) is presented. In these sensors, the small crackmeter range for the first field use is related to long-term observation on existing cracks in underground tunnel test sections.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001437740
|
oai_dc
|
Vibration-based structural health monitoring using large sensor networks
|
Vibration-based structural health monitoring using large sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Deraemaeker(Universitaires de Bruxelles); A. Preumont(Universitaires de Bruxelles); E. Reynders(Katholieke Universiteit Leuven); G. De Roeck(Katholieke Universiteit Leuven); J. Kullaa(Aalto University); V. Lämsä(Aalto University); K. Worden(University of Sheffield); G. Manson(University of Sheffield); R. Barthorpe(University of Sheffield); E. Papatheou(University of Sheffield); P. Kudela(Polish Academy of Science); P. Malinowski(Polish Academy of Science); W. Ostachowicz(Polish Academy of Science); T. Wandowski(Polish Academy of Science)"
] |
Recent advances in hardware and instrumentation technology have allowed the possibility of deploying very large sensor arrays on structures. Exploiting the huge amount of data that can result in order to perform vibration-based structural health monitoring (SHM) is not a trivial task and requires research into a number of specific problems. In terms of pressing problems of interest, this paper discusses: the design and optimisation of appropriate sensor networks, efficient data reduction techniques, efficient and automated feature extraction methods, reliable methods to deal with environmental and operational variability, efficient training of machine learning techniques and multi-scale approaches for dealing with very local damage. The paper is a result of the ESF-S3T Eurocores project Smart Sensing For Structural Health Monitoring(S3HM) in which a consortium of academic partners from across Europe are attempting to address issues in the design of automated vibration-based SHM systems for structures.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424583
|
oai_dc
|
Modeling and identification of a class of MR fluid foam dampers
|
Modeling and identification of a class of MR fluid foam dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mauricio Zapateiro(University of Girona); Ningsu Luo(University of Girona); Ellen Taylor(Washington University); Shirley J. Dyke(Purdue University)"
] |
This paper presents the results of a series of experiments conducted to model a magnetorheological damper operated in shear mode. The prototype MR damper consists of two parallel steel plates; a paddle covered with an MR fluid coated foam is placed between the plates. The force is generated when the paddle is in motion and the MR fluid is reached by the magnetic field of the coil in one end of the device. Two approaches were considered in this experiment: a parametric approach based on the Bingham, Bouc-Wen and Hyperbolic Tangent models and a non parametric approach based on a Neural Network model. The accuracy to reproduce the MR damper behavior is compared as well as some aspects related to performance are discussed.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424612
|
oai_dc
|
Damage assessment of structures - an US air force office of scientific research structural mechanics perspective
|
Damage assessment of structures - an US air force office of scientific research structural mechanics perspective
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Victor Giurgiutiu(University of South Carolina)"
] |
This paper presents the perspective of the Structural Mechanics program of the Air Force Office of Scientific Research (AFOSR) on the damage assessment of structures for the period 2006-2009 when the author was serving as Program Manager at AFOSR. It is found that damage assessment of structures plays a very important role in assuring the safety and operational readiness of US Air Force fleet. The current fleet has many aging aircraft, which poses a considerable challenge for the operators and maintainers. The nondestructive evaluation technology is rather mature and able to detect damage with considerable reliability during the periodic maintenance inspections. The emerging structural health monitoring methodology has great potential, because it will use on-board damage detection sensors and systems, will be able to offer on-demand structural health bulletins. Considerable fundamental and applied research is still needed to enable the development, implementation, and dissemination of structural health monitoring technology.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424623
|
oai_dc
|
Experimental studies on impact damage location in composite aerospace structures using genetic algorithms and neural networks
|
Experimental studies on impact damage location in composite aerospace structures using genetic algorithms and neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shahruddin Mahzan(Sheffield University); Wieslaw J. Staszewski(Sheffield University); Keith Worden(Sheffield University)"
] |
Impact damage detection in composite structures has gained a considerable interest in many engineering areas. The capability to detect damage at the early stages reduces any risk of catastrophic failure. This paper compares two advanced signal processing methods for impact location in composite aircraft structures. The first method is based on a modified triangulation procedure and Genetic Algorithms whereas the second technique applies Artificial Neural Networks. A series of impacts is performed experimentally on a composite aircraft wing-box structure instrumented with low-profile, bonded piezoceramic sensors. The strain data are used for learning in the Neural Network approach. The triangulation procedure utilises the same data to establish impact velocities for various angles of strain wave propagation. The study demonstrates that both approaches are capable of good impact location estimates in this complex structure.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424645
|
oai_dc
|
Control of PKM machine tools using piezoelectric self-sensing actuators on basis of the functional principle of a scale with a vibrating string
|
Control of PKM machine tools using piezoelectric self-sensing actuators on basis of the functional principle of a scale with a vibrating string
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Christian Rudolf(Universität Karlsruhe); Thomas Martin(Institut für Angewandte Informatik); Jörg Wauer(Universität Karlsruhe)"
] |
An adaptronic strut for machine tools with parallel kinematics for compensation of the influence of geometric errors is introduced. Implemented within the strut is a piezoelectric sensor-actuator unit separated in function. In the first part of this contribution, the functional principle of the strut is presented. For use of one piezoelectric transducer as both, sensor and actuator as so-called self-sensing actuator, the acquisition of the sensing signal while actuating simultaneously using electrical bridge circuits as well as filter properties are examined. In the second part the control concept developed for the adaptronic strut is presented. A co-simulation model of the strut for simulating the controlled multi-body behavior of the strut is set-up. The control design for the strut as a stand-alone system is tested under various external loads. Finally, the strut is implemented into a model of the complete machine tool and the influence of the controlled strut onto the behavior of the machine tool is examined.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424567
|
oai_dc
|
Active shape change of an SMA hybrid composite plate
|
Active shape change of an SMA hybrid composite plate
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Federica Daghia(University of Bologna); Daniel J. Inman(Virginia Polytechnic Institute and State University); Francesco Ubertini(University of Bologna); Erasmo Viola(University of Bologna)"
] |
An experimental study was carried out to investigate the shape control of plates via embedded shape memory alloy (SMA) wires. An extensive body of literature proposes the use of SMA wires to actively modify the shape or stiffness of a structure; in most cases, however, the study focuses on modeling and little experimental data is available. In this work, a simple proof of concept specimen was built by attaching four prestrained SMA wires to one side of a carbon fiber laminate plate strip. The specimen was clamped at one end and tested in an environmental chamber, measuring the tip displacement and the SMA temperature. At heating, actuation of the SMA wires bends the plate; at cooling deformation is partially recovered. The specimen was actuated a few times between two fixed temperatures Tc and Th, whereas in the last actuation a temperature Tf > Th was reached. Contrary to most model predictions, in the first actuation the transformation temperatures are significantly higher than in the following cycles, which are stable. Moreover, if the temperature Th is exceeded, two separate actuations occur during heating: the first follows the path of the stable cycles; the second, starting at Th, is similar to the first cycle. An interpretation of the phenomenon is given using some differential scanning calorimeter (DSC) measurements. The observed behavior emphasizes the need to build a more comprehensive constitutive model able to include these effects.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001424600
|
oai_dc
|
The application of modal filters for damage detection
|
The application of modal filters 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); Tadeusz Uhl(AGH University of Science and Technology)"
] |
A modal filter is a tool used to extract the modal coordinates of each individual mode from a system's output. This is achieved by mapping the response vector from the physical space to the modal space. It decomposes the system's responses into modal coordinates, and thus, on the output of the filter, the frequency response with only one peak corresponding to the natural frequency to which the filter was tuned can be obtained. As was shown in the paper (Deraemecker and Preumont 2006), structural modification (e.g. a drop in stiffness or mass due to damage) causes the appearance of spurious peaks on the output of the modal filter. A modal filter is, therefore, a great indicator of damage detection, with such advantages as low computational effort due to data reduction, ease of automation and lack of sensitivity to environmental changes. This paper presents the application of modal filters for the detection of stiffness changes. Two experiments were conducted: the first one using the simulation data obtained from the numerical 7DOF model, and the second one on the experimental data from a laboratory stand in 4 states of damage.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364175
|
oai_dc
|
A semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers
|
A semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Z. G. Ying(Zhejiang University); Y. Q. Ni(The Hong Kong Polytech. Univ.); J. M. Ko(The Hong Kong Polytechnic University)"
] |
A non-clipped semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers is developed based on the stochastic averaging method and stochastic dynamical programming principle. A nonlinear stochastic control structure is first modeled as a semi-actively controlled, stochastically excited and dissipated Hamiltonian system. The control force of an MR damper is separated into passive and semiactive
parts. The passive control force components, coupled in structural mode space, are incorporated in the drift coefficients by directly using the stochastic averaging method. Then the stochastic dynamical programming
principle is applied to establish a dynamical programming equation, from which the semi-active optimal control law is determined and implementable by MR dampers without clipping in terms of the Bingham model. Under the
condition on the control performance function given in section 3, the expressions of nonlinear and linear nonclipped semi-active optimal control force components are obtained as well as the non-clipped semi-active LQG
control force, and thus the value function and semi-active nonlinear optimal control force are actually existent according to the developed strategy. An example of the controlled stochastic hysteretic column is given to
illustrate the application and effectiveness of the developed semi-active optimal control strategy.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364182
|
oai_dc
|
Vibration and impedance monitoring for prestress-loss prediction in PSC girder bridges
|
Vibration and impedance monitoring for prestress-loss prediction in PSC girder bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김정태(부경대학교); 박재형(부경대학교); 홍동수(부경대학교); 조현만(부경대학교); 나원배(부경대학교); 이진학(Korea Ocean Research & Development Institute)"
] |
A vibration-impedance-based monitoring method is proposed to predict the loss of prestress forces in prestressed concrete (PSC) girder bridges. Firstly, a global damage alarming algorithm using the change in frequency responses is formulated to detect the occurrence of damage in PSC girders. Secondly, a local damage detection algorithm using the change in electro-mechanical impedance features is selected to identify the prestressloss in tendon and anchoring members. Thirdly, a prestress-loss prediction algorithm using the change in natural frequencies is selected to estimate the extent of prestress-loss in PSC girders. Finally, the feasibility of the proposed method is experimentally evaluated on a scaled PSC girder model for which acceleration responses and electro-mechanical impedances were measured for several damage scenarios of prestress-loss.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364170
|
oai_dc
|
A decentralized approach to damage localization through smart wireless sensors
|
A decentralized approach to damage localization through smart wireless sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"정민중(한국과학기술정보연구원); 고봉환(동국대학교)"
] |
This study introduces a novel approach for locating damage in a structure using wireless sensor system with local level computational capability to alleviate data traffic load on the centralized computation.
Smart wireless sensor systems, capable of iterative damage-searching, mimic an optimization process in a decentralized way. The proposed algorithm tries to detect damage in a structure by monitoring abnormal increases in strain measurements from a group of wireless sensors. Initially, this clustering technique provides a reasonably effective sensor placement within a structure. Sensor clustering also assigns a certain number of master sensors in each cluster so that they can constantly monitor the structural health of a structure. By adopting a voting system, a group of wireless sensors iteratively forages for a damage location as they can be activated as needed. Since all of the damage searching process occurs within a small group of wireless sensors, no global control or data traffic to a central system is required. Numerical simulation demonstrates that the newly developed searching algorithm implemented on wireless sensors successfully localizes stiffness damage in a plate through the local level reconfigurable function of smart sensors.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364173
|
oai_dc
|
Simulation and experimental analysis of active vibration control of smart beams under harmonic excitation
|
Simulation and experimental analysis of active vibration control of smart beams under harmonic excitation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. Malgaca(Dokuz Eylül University); H. Karagülle(Dokuz Eylül University)"
] |
In the present study, active control of a smart beam under forced vibration is analyzed. The aluminum smart beam is composed of two piezoelectric patches and strain gauge. One of the piezoelectric patches is used as controlling actuator while the other piezoelectric patch is used as vibration generating shaker. The smart beam is harmonically excited by the piezoelectric shaker at its fundamental frequency. The strain gauge is utilized
to sense the vibration level. Active vibration reduction under harmonic excitation is achieved using both strain and displacement feedback control. Control actions, the finite element (FE) modeling and analyses are directly carried out by using ANSYS parametric design language (APDL). Experimental applications are performed with LabVIEW.
Dynamic behavior at the tip of the beam is evaluated for the uncontrolled and controlled responses. The simulation and experimental results are compared. Good agreement is observed between simulation and experimental results
under harmonic excitation.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364168
|
oai_dc
|
Static analysis of rubber components with piezoelectric patches using nonlinear finite element
|
Static analysis of rubber components with piezoelectric patches using nonlinear finite element
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. C. Manna(B. E. College); A. H. Sheikh(The University of Adelaide); R. Bhattacharyya(Indian Institute of Technology)"
] |
In order to reduce vibration or to control shape of structures made of metal or composites, piezoelectric materials have been extensively used since their discovery in 1880’s. A recent trend is also seen to apply piezoelectric materials to flexible structures made of rubber-like materials. In this paper a non-linear finite element model using updated Lagrangian (UL) approach has been developed for static analysis of rubber-elastic material with surface-bonded piezoelectric patches. A compressible stain energy function has been used for modeling the rubber as hyperelastic material. For formulation of the nonlinear finite element model a twenty-node brick element is used. Four degrees of freedom u, v and w and electrical potential ϕ per node are considered as the field variables. PVDF (polyvinylidene fluoride) patches are applied as sensors/actuators or sensors and actuators.
The present model has been applied to bimorph PVDF cantilever beam to validate the formulation. It is then applied to study the smart rubber components under different boundary and loading conditions. The results
predicted by the present formulation are compared with the analytical solutions as well as the available published results. Some results are given as new ones as no published solutions available in the literatures to the best of the authors’ knowledge.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364165
|
oai_dc
|
A two-stage damage detection approach based on subset selection and genetic algorithms
|
A two-stage damage detection approach based on subset selection and genetic algorithms
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gun Jin Yun(The University of Akron); Kenneth A. Ogorzalek(University of Wisconsin-Milwaukee); Shirley J. Dyke(Washington University); Wei Song(Washington University)"
] |
A two-stage damage detection method is proposed and demonstrated for structural health monitoring. In the first stage, the subset selection method is applied for the identification of the multiple damage locations. In the second stage, the damage severities of the identified damaged elements are determined applying SSGA to solve the optimization problem. In this method, the sensitivities of residual force vectors with respect to damage
parameters are employed for the subset selection process. This approach is particularly efficient in detecting multiple damage locations. The SEREP is applied as needed to expand the identified mode shapes while using a
limited number of sensors. Uncertainties in the stiffness of the elements are also considered as a source of modeling errors to investigate their effects on the performance of the proposed method in detecting damage in real-life structures. Through a series of illustrative examples, the proposed two-stage damage detection method is demonstrated to be a reliable tool for identifying and quantifying multiple damage locations within diverse structural systems.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364181
|
oai_dc
|
Application of time series based damage detection algorithms to the benchmark experiment at the National Center for Research on Earthquake Engineering (NCREE) in Taipei, Taiwan
|
Application of time series based damage detection algorithms to the benchmark experiment at the National Center for Research on Earthquake Engineering (NCREE) in Taipei, Taiwan
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hae Young Noh(Stanford University); Krishnan Nair(Stanford University); Anne S. Kiremidjian(Stanford University); C-H. Loh(National Taiwan University)"
] |
In this paper, the time series based damage detection algorithms developed by Nair, et al. (2006) and Nair and Kiremidjian (2007) are applied to the benchmark experimental data from the National Center for Research on Earthquake Engineering (NCREE) in Taipei, Taiwan. Both acceleration and strain data are analyzed. The data are modeled as autoregressive (AR) processes, and damage sensitive features (DSF) and feature vectors are defined in terms of the first three AR coefficients. In the first algorithm developed by Nair, et al. (2006), hypothesis tests using the t-statistic are applied to evaluate the damaged state. A damage measure (DM) is defined to measure the damage extent. The results show that the DSF’s from the
acceleration data can detect damage while the DSF from the strain data can be used to localize the damage.
The DM can be used for damage quantification. In the second algorithm developed by Nair and Kiremidjian (2007) a Gaussian Mixture Model (GMM) is used to model the feature vector, and the Mahalanobis distance is defined to measure damage extent. Additional distance measures are defined and applied in this paper to quantify damage. The results show that damage measures can be used to detect, quantify, and localize the damage for the high intensity and the bidirectional loading cases.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362541
|
oai_dc
|
Health monitoring of a bridge system using strong motion data
|
Health monitoring of a bridge system using strong motion data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. M. Mosalam(University of California); Y. Arici(Middle East Technical University)"
] |
In this paper, the acceptability of system identification results for health monitoring of instrumented bridges is addressed. This is conducted by comparing the confidence intervals of identified modal parameters for a
bridge in California, namely Truckee I80/Truckee river bridge, with the change of these parameters caused by several damage scenarios. A challenge to the accuracy of the identified modal parameters involves consequences
regarding the damage detection and health monitoring, as some of the identified modal information is essentially not useable for acquiring a reliable damage diagnosis of the bridge system. Use of strong motion data has
limitations that should not be ignored. The results and conclusions underline these limitations while presenting the opportunities offered by system identification using strong motion data for better understanding and monitoring
the health of bridge systems.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362457
|
oai_dc
|
Real time crack detection using mountable comparative vacuum monitoring sensors
|
Real time crack detection using mountable comparative vacuum monitoring sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"D. Roach(Sandia National Laboratories)"
] |
Current maintenance operations and integrity checks on a wide array of structures require personnel entry into normally-inaccessible or hazardous areas to perform necessary nondestructive inspections. To gain access for these inspections, structure must be disassembled and removed or personnel must be transported to remote locations. The use of in-situ sensors, coupled with remote interrogation, can be employed to overcome a myriad of inspection impediments stemming from accessibility limitations, complex geometries, the location and depth of hidden damage, and the isolated location of the structure. Furthermore, prevention of unexpected flaw growth and structural failure could be improved if on-board health monitoring systems were used to more regularly assess structural integrity. A research program has been completed to develop and validate Comparative Vacuum Monitoring (CVM) Sensors for surface crack detection. Statistical methods using one-sided tolerance intervals were employed to derive Probability of Detection (POD) levels for a wide array of application scenarios.
Multi-year field tests were also conducted to study the deployment and long-term operation of CVM sensors on aircraft. This paper presents the quantitative crack detection capabilities of the CVM sensor, its performance in
actual flight environments, and the prospects for structural health monitoring applications on aircraft and other civil structures.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362506
|
oai_dc
|
Diagnostic/prognostic health monitoring system and evaluation of a composite bridge
|
Diagnostic/prognostic health monitoring system and evaluation of a composite bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Mosallam(University of California); R. Miraj(University of California); F. Abdi(AlphaSTAR Corporation)"
] |
Composite bridges offer many advantages compared to current steel and aluminum bridges. This paper presents the results of a comprehensive on-going research program to develop innovative Diagnostic Prognostic System (DPS) and a structural evaluation of Composite Army Bridge (CAB) system. The DPS is founded on three technologies: optical fiber sensing, remote data transmission, and virtual testing. In developing this system, both laboratory and virtual test were used in different damage scenarios. Health monitoring with DPS entailed comparing live strain data to archived strained data in various bridge locations. For field repairs, a family of composite chords was subjected to simple ramp loads in search of ultimate strength. As such, composite bridge specimens showcased their strengths, heralded the viability of virtual testing, highlighted the efficacy of field repair, and confirmed the merits of health monitoring.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001363025
|
oai_dc
|
Post earthquake performance monitoring of a typical highway overpass bridge
|
Post earthquake performance monitoring of a typical highway overpass bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Iranmanesh(University of Illinois at Chicago); A. Bassam(University of Illinois at Chicago); F. Ansari(University of Illinois at Chicago)"
] |
Bridges form crucial links in the transportation network especially in high seismic risk regions. This research aims to provide a quantitative methodology for post-earthquake performance evaluation of the bridges.
The experimental portion of the research involved shake table tests of a 4-span bridge which was subjected to progressively increasing amplitudes of seismic motions recorded from the Northridge earthquake. As part of this
project, a high resolution long gauge fiber optic displacement sensor was developed for post-seismic evaluation of damage in the columns of the bridge. The nonlinear finite element model was developed using Opensees program to simulate the response of the bridge and the abutments to the seismic loads. The model was modified to predict the bent displacements of the bridge commensurate with the measured bent displacements obtained from
experimental analysis results. Following seismic events, the tangential stiffness matrix of the whole structure is reduced due to reduction in structural strength. The nonlinear static push over analysis using current damaged
stiffness matrix provides the longitudinal and transverse ultimate capacities of the bridge. Capacity loss in the transverse and longitudinal directions following the seismic events was correlated to the maximum displacements
of the deck recorded during the events.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362543
|
oai_dc
|
Damage characterization of beam-column joints reinforced with GFRP under reversed cyclic loading
|
Damage characterization of beam-column joints reinforced with GFRP under reversed cyclic loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. M. Said(University of Nevada)"
] |
The use of fiber reinforced polymer (FRP) reinforcement in concrete structures has been on the rise due to its advantages over conventional steel reinforcement such as corrosion. Reinforcing steel corrosion has been the primary cause of deterioration of reinforced concrete (RC) structures, resulting in tremendous annual repair costs. One application of FRP reinforcement to be further explored is its use in RC frames. Nonetheless, due
to FRP’s inherently elastic behavior, FRP-reinforced (FRP-RC) members exhibit low ductility and energy dissipation as well as different damage mechanisms. Furthermore, current design standards for FRP-RC structures
do not address seismic design in which the beam-column joint is a key issue. During an earthquake, the safety of beam-column joints is essential to the whole structure integrity. Thus, research is needed to gain better
understanding of the behavior of FRP-RC structures and their damage mechanisms under seismic loading. In this study, two full-scale beam-column joint specimens reinforced with steel and GFRP configurations were tested
under quasi-static loading. The control steel-reinforced specimen was detailed according to current design code provisions. The GFRP-RC specimen was detailed in a similar scheme. The damage in the two specimens is characterized to compare their performance under simulated seismic loading.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362489
|
oai_dc
|
Entropy-based optimal sensor networks for structural health monitoring of a cable-stayed bridge
|
Entropy-based optimal sensor networks for structural health monitoring of a cable-stayed bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Azarbayejani(University of New Mexico); A. I. El-Osery(New Mexico Tech); M. M. Reda Taha(University of New Mexico)"
] |
The sudden collapse of Interstate 35 Bridge in Minneapolis gave a wake-up call to US municipalities to re-evaluate aging bridges. In this situation, structural health monitoring (SHM) technology can provide the essential help needed for monitoring and maintaining the nation’s infrastructure. Monitoring long span bridges such as cable-stayed bridges effectively requires the use of a large number of sensors. In this article, we introduce a probabilistic approach to identify optimal locations of sensors to enhance damage detection. Probability distribution functions are established using an artificial neural network trained using a priori knowledge of damage locations.
The optimal number of sensors is identified using multi-objective optimization that simultaneously considers information entropy and sensor cost-objective functions. Luling Bridge, a cable-stayed bridge over the Mississippi River, is selected as a case study to demonstrate the efficiency of the proposed approach.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362553
|
oai_dc
|
Application of structural health monitoring in civil infrastructure
|
Application of structural health monitoring in civil infrastructure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Q. Feng(University of California)"
] |
The emerging sensor-based structural health monitoring (SHM) technology has a potential for costeffective maintenance of aging civil infrastructure systems. The author proposes to integrate continuous and global
monitoring using on-structure sensors with targeted local non-destructive evaluation (NDE). Significant technical challenges arise, however, from the lack of cost-effective sensors for monitoring spatially large structures, as well
as reliable methods for interpreting sensor data into structural health conditions. This paper reviews recent efforts and advances made in addressing these challenges, with example sensor hardware and health monitoring software developed in the author’s research center. The hardware includes a novel fiber optic accelerometer, a vision-based displacement sensor, a distributed strain sensor, and a microwave imaging NDE device. The health monitoring software includes a number of system identification methods such as the neural networks, extended Kalman filter,and nonlinear damping identificaiton based on structural dynamic response measurement. These methods have been experimentally validated through seismic shaking table tests of a realistic bridge model and tested in a number of instrumented bridges and buildings.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362498
|
oai_dc
|
Condition assessment of reinforced concrete bridges using structural health monitoring techniques - A case study
|
Condition assessment of reinforced concrete bridges using structural health monitoring techniques - A case study
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"E. Mehrani(DCI Solutions Inc.); A. Ayoub(University of Houston)"
] |
The paper presents a case study in which the structural condition assessment of the East Bay bridge in Gibsonton, Florida is evaluated with the help of remote health monitoring techniques. The bridge is a four-span,
continuous, deck-type reinforced concrete structure supported on prestressed pile bents, and is instrumented with smart Fiber Optic Sensors. The sensors used for remote health monitoring are the newly emerged Fabry –Perot (FP), and are both surface-mounted and embedded in the deck. The sensing system can be accessed remotely through fast Digital Subscriber Lines (DSL), which permits the evaluation of the bridge behavior under live traffic loads. The bridge was open to traffic since March 2005, and the collected structural data have been continuously analyzed since. The data revealed an increase in strain readings, which suggests a progression in damage. Recent visual observations also indicated the presence of longitudinal cracks along the bridge length. After the formation of these cracks, the sensors readings were analyzed and used to extrapolate the values of the maximum stresses at the crack location. The data obtained were also compared to initial design values of the bridge under factored gravity
and live loads. The study showed that the proposed structural health monitoring technique proved to provide an efficient mean for condition assessment of bridge structures providing it is implemented and analyzed with care.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362539
|
oai_dc
|
BRAIN: A bivariate data-driven approach to damage detection in multi-scale wireless sensor networks
|
BRAIN: A bivariate data-driven approach to damage detection in multi-scale wireless sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. Kijewski-Correa(University of Notre Dame); S. Su(University of Notre Dame)"
] |
This study focuses on the concept of multi-scale wireless sensor networks for damage detection in civil infrastructure systems by first over viewing the general network philosophy and attributes in the areas of data acquisition, data reduction, assessment and decision making. The data acquisition aspect includes a scalable wireless sensor network acquiring acceleration and strain data, triggered using a Restricted Input Network Activation scheme (RINAS) that extends network lifetime and reduces the size of the requisite undamaged reference pool. Major emphasis is given in this study to data reduction and assessment aspects that enable a decentralized approach operating within the hardware and power constraints of wireless sensor networks to avoid issues associated with packet loss, synchronization and latency. After over viewing various models for data reduction, the concept of a data-driven Bivariate Regressive Adaptive INdex (BRAIN) for damage detection is presented. Subsequent examples using experimental and simulated data verify two major hypotheses related to the BRAIN concept: (i) data-driven damage metrics are more robust and reliable than their counterparts and (ii) the use of heterogeneous sensing enhances overall detection capability of such data-driven damage metrics.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001363022
|
oai_dc
|
Photonic sensors for micro-damage detection: A proof of concept using numerical simulation
|
Photonic sensors for micro-damage detection: A proof of concept using numerical simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Sheyka(University of New Mexico); I. El-Kady(University of New Mexico); M. F. Su(University of New Mexico); M. M. Reda Taha(University of New Mexico)"
] |
Damage detection has been proven to be a challenging task in structural health monitoring (SHM) due to the fact that damage cannot be measured. The difficulty associated with damage detection is related to electing a feature that is sensitive to damage occurrence and evolution. This difficulty increases as the damage size decreases limiting the ability to detect damage occurrence at the micron and submicron length scale. Damage detection at this length scale is of interest for sensitive structures such as aircrafts and nuclear facilities. In this paper a new photonic sensor based on photonic crystal (PhC) technology that can be synthesized at the nanoscale
is introduced. PhCs are synthetic materials that are capable of controlling light propagation by creating a photonic bandgap where light is forbidden to propagate. The interesting feature of PhC is that its photonic signature is
strongly tied to its microstructure periodicity. This study demonstrates that when a PhC sensor adhered to polymer substrate experiences micron or submicron damage, it will experience changes in its microstructural periodicity
thereby creating a photonic signature that can be related to damage severity. This concept is validated here using a three-dimensional integrated numerical simulation.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362481
|
oai_dc
|
Practicalities of structural health monitoring
|
Practicalities of structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P. L. Shrive(Halcrow Yolles); T. G. Brown(Univ. of Calgary); N. G. Shrive(Univ. of Calgary)"
] |
Structural Health Monitoring (SHM), particularly remote monitoring, is an emerging field with great potential to help infrastructure owners obtain more and up-to-date knowledge of their structures. The methodology could provide supplemental information to guide the frequency and extent of visual inspections, and the possible need for maintenance. The instrumentation for a SHM system needs to be developed with longevity and the objectives for the system in mind. Sensors need to be selected for reliability and durability, sited where they provide the maximum information for the objectives, and where they can be accessed and replaced should the need arise over the monitoring period. With the rapid changes now occurring with sensors and software, flexibility needs to be in place to allow the system to be upgraded over time. Damage detection needs to be considered in terms of the type of damage that needs to be detected, informing maintenance requirements, and how detection can be achieved. Current vibration analysis techniques appear not yet to have achieved the necessary sensitivity for that purpose. Societal factors will influence the design of a SHM system in terms of the ophistication of the instrumentation and methodology employed.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362551
|
oai_dc
|
Developing an integrated software solution for active-sensing SHM
|
Developing an integrated software solution for active-sensing SHM
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. G. Overly(Los Alamos National Laboratory); L. D. Jacobs(Los Alamos National Laboratory); K. M. Farinholt(Los Alamos National Laboratory); G. Park(Los Alamos National Laboratory); C. R. Farrar(Los Alamos Lab.); E. B. Flynn(University of California); M. D. Todd(University of California San Diego)"
] |
A novel approach for integrating active sensing data interrogation algorithms for structural health monitoring (SHM) applications is presented. These algorithms cover Lamb wave propagation, impedance methods, and sensor diagnostics. Contrary to most active-sensing SHM techniques, which utilize only a single signal processing method for damage identification, a suite of signal processing algorithms are employed and grouped into one package to improve the damage detection capability. A MATLAB-based user interface, referred to as HOPS, was created, which allows the analyst to configure the data acquisition system and display the results from each damage identification algorithm for side-by-side comparison. By grouping a suite of algorithms into one package, this study contributes to and enhances the visibility and interpretation of the active-sensing methods related to damage identification. This paper will discuss the detailed descriptions of the damage identification techniques employed in this software and outline future issues to realize the full potential of this software.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362473
|
oai_dc
|
Serially multiplexed FBG accelerometer for structural health monitoring of bridges
|
Serially multiplexed FBG accelerometer for structural health monitoring of bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"I. Talebinejad(University of Illinois at Chicago); C. Fischer(University of Illinois at Chicago); F. Ansari(University of Illinois at Chicago)"
] |
This article describes the development of a fiber optic accelerometer based on Fiber Bragg Gratings (FBG). The accelerometer utilizes the stiffness of the optical fiber and a lumped mass in the design. Acceleration is measured by the FBG in response to the vibration of the fiber optic mass system. The wavelength shift of FBG is proportional to the change in acceleration, and the gauge factor pertains to the shift in wavelength as a function of acceleration. Low frequency version of the accelerometer was developed for applications in monitoring bridges.
The accelerometer was first evaluated in laboratory settings and then employed in a demonstration project for condition assessment of a bridge. Laboratory experiments involved evaluation of the sensitivity and resolution of
measurements under a series of low frequency low amplitude conditions. The main feature of this accelerometer is single channel multiplexing capability rendering the system highly practical for application in condition assessment
of bridges. This feature of the accelerometer was evaluated by using the system during ambient vibration tests of a bridge. The Frequency Domain Decomposition method was employed to identify the mode shapes and natural
frequencies of the bridge. Results were compared with the data acquired from the conventional accelerometers.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362468
|
oai_dc
|
Damage state evaluation of experimental and simulated bolted joints using chaotic ultrasonic waves
|
Damage state evaluation of experimental and simulated bolted joints using chaotic ultrasonic waves
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. R. Fasel(University of California San Diego); M. B. Kennel(University of California San Diego); M. D. Todd(University of California San Diego); E. H. Clayton(Quartus Engineering); G. Park(Los Alamos National Laboratory)"
] |
Ultrasonic chaotic excitations combined with sensor prediction algorithms have shown the ability to identify incipient damage (loss of preload) in a bolted joint. In this study we examine a physical experiment on a single-bolt aluminum lap joint as well as a three-dimensional physics-based simulation designed to model the behavior of guided ultrasonic waves through a similarly configured joint. A multiple bolt frame structure is also experimentally examined. In the physical experiment each signal is imparted to the structure through a macro-fiber composite (MFC) patch on one side of the lap joint and sensed using an equivalent MFC patch on the opposite side of the joint. The model applies the waveform via direct nodal displacement and ‘senses’ the resulting displacement using an average of the nodal strain over an area equivalent to the MFC patch. A novel statistical classification feature is developed from information theory concepts of cross-prediction and interdependence. This damage detection algorithm is used to evaluate multiple damage levels and locations.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364222
|
oai_dc
|
Comparisons of smart damping treatments based on FEM modeling of electromechanical impedance
|
Comparisons of smart damping treatments based on FEM modeling of electromechanical impedance
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. P. Providakis(Technical University of Crete); D.-P. N. Kontoni(Technological Educational Institute of Patras); M. E. Voutetaki(Technical University of Crete); M. E. Stavroulaki(Technical University of Crete)"
] |
In this paper the authors address the problem of comparing two different smart damping techniques using the numerical modelling of the electro-mechanical impedance for plate structures partially treated with active constrained layer damping treatments. The paper summarizes the modelling procedures including a finite element formulation capable of accounting for the observed behaviour. The example used is a smart cantilever plate structure containing a viscoelastic material (VEM) layer sandwiched between a piezoelectric constrained layer and the host vibrating plate. Comparisons are made between active constrained layer and active damping only and based on the resonance frequency amplitudes of the electrical admittance numerically evaluated at the surface of the piezoelectric model of the vibrating structure.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001362438
|
oai_dc
|
A simple approach for quality evaluation of non-slender, cast-in-place piles
|
A simple approach for quality evaluation of non-slender, cast-in-place piles
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ray Ruichong Zhang(Colorado School of Mines)"
] |
This study proposes a conceptual framework of in-situ vibration tests and analyses for quality appraisal of non-slender, cast-in-place piles with irregular cross-section configuration. It evaluates a frequency index from vibration recordings to a series of impulse loadings that is related to total soil-resistance forces around a pile, so as to assess if the pile achieves the design requirement in terms of bearing capacity. In particular, in-situ pile-vibration tests in sequential are carried out, in which dropping a weight from different heights generates series impulse loadings with low-to-high amplitudes. The high-amplitude impulse is designed in way that the load will generate equivalent static load that is equal to or larger than the designed
bearing capacity of the pile. This study then uses empirical mode decomposition and Hilbert spectral analysis for processing the nonstationary, short-period recordings, so as to single out with accuracy the frequency
index. Comparison of the frequency indices identified from the recordings to the series loadings with the design-based one would tell if the total soil resistance force remains linear or nonlinear and subsequently for the quality appraisal of the pile. As an example, this study investigates six data sets collected from the in-situ tests of two piles in Taipu water pump project, Jiangshu Province of China. It concludes that the two piles have the actual axial load capacity higher than the designed bearing capacity. The true bearing capacity of the piles under investigation can be estimated with accuracy if the amplitude of impact loadings is further increased and the analyses are calibrated with the static testing results.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001464187
|
oai_dc
|
Design of an actuator for simulating wind-induced response of a building structure
|
Design of an actuator for simulating wind-induced response of a building structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박은천(단국대학교); 이상현(단국대학교); 민경원(단국대학교); 정란(단국대학교); 이성경(단국대학교); 조승호(단국대학교); 유은종(한양대학교); 강경수(동명대학교)"
] |
In this paper, excitation systems using a linear mass shaker (LMS) and an active tuned mass damper (ATMD) are presented to simulate the wind induced responses of a building structure. The actuator force for the excitation systems is calculated by using the inverse transfer function of a target structural response to the actuator. Filter and envelop functions are used to prevent the actuator from exciting unexpected modal responses and an initial transient response and thus, to minimize the error between the wind and actuator induced responses. The analyses results from a 76-story benchmark building problem for which the wind load obtained by a wind tunnel test is given, indicate that the excitation system installed at a specific floor can approximately reproduce the structural responses induced by the wind load applied to each floor of the structure. The excitation system designed by the proposed method can be effectively used for evaluating the wind response characteristics of a practical building structure and for obtaining an accurate analytical model of the building under wind load.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364223
|
oai_dc
|
Health monitoring of multistoreyed shear building using parametric state space modeling
|
Health monitoring of multistoreyed shear building using parametric state space modeling
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Manab Medhi(Indian Institute of Technology); Anjan Dutta(Indian Institute of Technology); S. K. Deb(Indian Institute of Technology)"
] |
The present work utilizes system identification technique for health monitoring of shear building, wherein Parametric State Space modeling has been adopted. The method requires input excitation to the structure and also output acceleration responses of both undamaged and damaged structure obtained from numerically simulated model. Modal parameters like eigen frequencies and eigen vectors have been extracted from the State Space model after introducing appropriate transformation. Least square technique has been
utilized for the evaluation of the stiffness matrix after having obtained the modal matrix for the entire structure. Highly accurate values of stiffness of the structure could be evaluated corresponding to both the undamaged as well as damaged state of a structure, while considering noise in the simulated output response analogous to real time scenario. The damaged floor could also be located very conveniently and accurately by this adopted strategy. This method of damage detection can be applied in case of output acceleration responses recorded by sensors from the actual structure. Further, in case of even limited availability of sensors along the height of a multi-storeyed building, the methodology could yield very accurate information related to structural stiffness.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001364221
|
oai_dc
|
Second-order statistics of natural frequencies of smart laminated composite plates with random material properties
|
Second-order statistics of natural frequencies of smart laminated composite plates with random material properties
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"B. N. Singh(Indian Institute of Technology Kharagpur); Atul Umrao(MN National Inst. of Technology); K. K. Shukla(Motilal Nehru National Institute of Tech.); N. Vyas(IIT Kharagpur)"
] |
Nowadays developments in the field of laminated composite structures with piezoelectric have attracted significant attention of researchers due to their wide range of applications in engineering such as sensors, actuators, vibration suppression, shape control, noise attenuation and precision positioning. Due to large number of parameters associated with its manufacturing and fabrication, composite structures with piezoelectric display a considerable amount of uncertainty in their material properties. The present work investigates the effect of the uncertainty on the free vibration response of piezoelectric laminated composite plate. The lamina material properties have been modeled as independent random variables for accurate prediction of the system behavior. System equations have been derived using higher order shear deformation theory. A finite element method in conjunction with Monte Carlo simulation is employed to obtain the secondorder statistics of the natural frequencies. Typical results are presented for all edges simply supported piezoelectric laminated composite plates to show the influence of scattering in material properties on the second order statistics of the natural frequencies. The results have been compared with those available in iterature.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001464182
|
oai_dc
|
On the static and dynamic stability of beams with an axial piezoelectric actuation
|
On the static and dynamic stability of beams with an axial piezoelectric actuation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. Zehetner(Linz Center of Competence in Mechatronics); H. Irschik(Johannes Kepler University of Linz)"
] |
The present contribution is concerned with the static and dynamic stability of a piezo-laminated Bernoulli-Euler beam subjected to an axial compressive force. Recently, an inconsistent derivation of the equations of motions of such a smart structural system has been presented in the literature, where it has been claimed, that an axial piezoelectric actuation can be used to control its stability. The main scope of the present paper is to show that this unfortunately is impossible. We present a consistent theory for composite beams in plane bending. Using an exact description of the kinematics of the beam axis, together with the Bernoulli-Euler assumptions, we obtain a single-layer theory capable of taking into account the effects of piezoelectric
actuation and buckling. The assumption of an inextensible beam axis, which is frequently used in the literature, is discussed afterwards. We show that the cited inconsistent beam model is due to inadmissible mixing of the assumptions of an inextensible beam axis and a vanishing axial displacement, leading to the erroneous result that the stability might be enhanced by an axial piezoelectric actuation. Our analytical formulations for simply supported Bernoulli-Euler type beams are verified by means of three-dimensional finite element computations performed with ABAQUS.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001464189
|
oai_dc
|
Damage evaluation through radial basis function network based artificial neural network scheme
|
Damage evaluation through radial basis function network based artificial neural network scheme
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"N. Lakshmanan(Structural Engineering Research Centre); B. K. Raghuprasad(Indian Institute of Science); K. Muthumani(Structural Engineering Research Centre); N. Gopalakrishnan(Structural Engineering Research Centre); D. Basu(Structural Engineering Research Centre)"
] |
토목공학
| null |
kci_detailed_000093.xml
|
||||
ART001390051
|
oai_dc
|
Ni-Ti actuators and genetically optimized compliant ribs for an adaptive wing
|
Ni-Ti actuators and genetically optimized compliant ribs for an adaptive wing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Giuseppe Mirone(University of Catania)"
] |
Adaptive wings are capable of properly modifying their shape depending on the current aerodynamic conditions, in order to improve the overall performance of a flying vehicle. In this paper is presented the concept
design of a small-scale compliant wing rib whose outline may be distorted in order to switch from an aerodynamic profile to another. The distortion loads are induced by shape memory alloy actuators placed within the frame of a
wing section whose elastic response is predicted by the matrix method with beam formulation. Genetic optimization is used to find a wing rib structure (corresponding to the first airfoil) able to properly deforms itself when loaded
by the SMA-induced forces, becoming as close as possible to the desired target shape (second airfoil). An experimental validation of the design procedure is also carried out with reference to a simplified structure layout.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001390050
|
oai_dc
|
Detection of edge delamination in surface adhered active fiber composites
|
Detection of edge delamination in surface adhered active fiber composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dwo-Wen Wang(National Chiao Tung University); Ching-Chung Yin(National Chiao Tung University)"
] |
A simple method has been developed to detect the bonding condition of active fiber composites(AFC) adhered to the surface of a host structure. Large deformation actuating capability is one of important features of AFC. Edge delamination in adhesive layer due to large interfacial shear stress at the free edge is typically resulted from axial strain mismatch between bonded materials. AFC patch possesses very good flexibility and toughness. When an AFC patch is partially delaminated from host structure, there remains sensing
capability in the debonded part. The debonding size can be determined through axial resonance measured by the interdigitated electrodes symmetrically aligned on opposite surfaces of the patch. The electrical impedance and modal response of the AFC patch in part adhered to an aluminum plate were investigated in a broad frequency range. Debonding ratio of the AFC patch is in inverse proportion to the resonant frequency of the fundamental mode. Feasibility of in-situ detecting the progressive delamination between AFC patch and host plate is demonstrated.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001390053
|
oai_dc
|
Optimized finite element model updating method for damage detection using limited sensor information
|
Optimized finite element model updating method for damage detection using limited sensor information
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. Cheng(Shenzhen University); H. C. Xie(Shenzhen University); B. F. Spencer, Jr.(University of Illinois); R. K. Giles(University of Illinois at Urbana-Champaign)"
] |
Limited, noisy data in vibration testing is a hindrance to the development of structural damage detection. This paper presents a method for optimizing sensor placement and performing damage detection using finite element model updating. Sensitivity analysis of the modal flexibility matrix determines the optimal sensor locations for collecting information on structural damage. The optimal sensor locations require the instrumentation of only a limited number of degrees of freedom. Using noisy modal data from only these limited sensor locations, a method based on model updating and changes in the flexibility matrix successfully determines the location and severity of the imposed damage in numerical simulations. In addition, a steel cantilever beam experiment performed in the laboratory that considered the effects of model error and noise tested the validity of the method. The results show that the proposed approach effectively and robustly detects structural damage using limited, optimal sensor information.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001390048
|
oai_dc
|
New insights in piezoelectric free-vibrations using simplified modeling and analyses
|
New insights in piezoelectric free-vibrations using simplified modeling and analyses
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ayech Benjeddou(Institut Supérieur de Mécanique de Paris)"
] |
New insights are presented in simplified modeling and analysis of free vibrations of piezoelectric-based smart structures and systems. These consist, first, in extending the wide used piezoelectric–thermal analogy
(TA) simplified modeling approach in currently static actuation to piezoelectric free–vibrations under short-circuit(SC) and approximate open-circuit (OC) electric conditions; second, the popular piezoelectric strain induced –potential (IP) simplified modeling concept is revisited. It is shown that the IP resulting frequencies are insensitive to the electric SC/OC conditions; in particular, SC frequencies are found to be the same as those resulting from the newly proposed OC TA. Two-dimensional plane strain (PStrain) and plane stress (PStress) free-vibrations problems are then analyzed for above used SC and approximate OC electric conditions. It is shown theoretically and validated numerically that, for both SC and OC electric conditions, PStress frequencies are lower than PStrain ones, and that 3D frequencies are bounded from below by the former and from above by the latter. The same holds for the modal electro-mechanical coupling coefficient that is retained as a comparator of presented models and analyses.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001390052
|
oai_dc
|
Design and characterization of a compact array of MEMS accelerometers for geotechnical instrumentation
|
Design and characterization of a compact array of MEMS accelerometers for geotechnical instrumentation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"V. Bennett(Rensselaer Polytechnic Institute); T. Abdoun(Rensselaer Polytechnic Institute); T. Shantz(California Department of Transportation); D. Jang(California Department of Transportation); S. Thevanayagam(University at Buffalo)"
] |
The use of Micro-Electro-Mechanical Systems (MEMS) accelerometers in geotechnical instrumentation is relatively new but on the rise. This paper describes a new MEMS-based system for in situ deformation and vibration monitoring. The system has been developed in an effort to combine recent advances in the miniaturization of sensors and electronics with an established wireless infrastructure for on-line geotechnical monitoring. The concept is based on triaxial MEMS accelerometer measurements of static acceleration (angles relative to gravity) and dynamic accelerations. The dynamic acceleration sensitivity range provides signals proportional to vibration during earthquakes or construction activities. This MEMS-based in-place inclinometer system utilizes the measurements to obtain three- dimensional (3D) ground acceleration and permanent deformation profiles up to a depth of one hundred meters. Each sensor array or group of arrays can be connected to a wireless earth station to enable real-time monitoring as well as remote sensor configuration. This paper provides a technical assessment of MEMS-based in-place inclinometer systems for geotechnical instrumentation applications by reviewing the sensor characteristics and providing small- and full-scale laboratory calibration tests. A description and
validation of recorded field data from an instrumented unstable slope in California is also presented.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001390049
|
oai_dc
|
Dynamic displacement tracking of a one-storey frame structure using patch actuator networks: Analytical plate solution and FE validation
|
Dynamic displacement tracking of a one-storey frame structure using patch actuator networks: Analytical plate solution and FE validation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Daniel Huber(Linz Center of Mechatronics GmbH); Hans Irschik(Johannes Kepler University Linz); Michael Krommer(Johannes Kepler University Linz)"
] |
The present paper is concerned with the design of a proper patch actuator network in order to track a desired displacement of the sidewalls of a one-storey frame structure; both, for the static and the dynamic case. Weights for each patch of the actuator network found in our previous work were based on beam theory; in the present paper a refinement of these weights by modeling the sidewalls of the frame structure as thin plates is presented. For the sake of calculating the refined weights approximate solutions of the plate equations are calculated by an extended Galerkin method. The solutions based on the analytical plate model are compared with three-dimensional Finite Element results computed in the commercially available code ANSYS. The patch actuator network is put into practice by means of four piezoelectric patches attached to each of the two sidewalls of the frame structures, to which electric voltages proportional to the analytically refined patch weights are applied. Analytical and numerical results coincide very well over a broad frequency range.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001375571
|
oai_dc
|
Spline finite strip method incorporating different plate theories for thick piezoelectric composite plates
|
Spline finite strip method incorporating different plate theories for thick piezoelectric composite plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"G. Akhras(Royal Military College of Canada); W. C. Li(Royal Military College of Canada)"
] |
In the present analysis, the spline finite strip with higher-order shear deformation is formulated for the static analysis of piezoelectric composite plates. The proposed method incorporates Reddy’s third-order shear
deformation theory, Touratier’s “Sine” model, Afaq’s exponential model, Cho’s higher-order zigzag laminate theory, as well as the classic plate theory and the first-order plate theory. Thus, the analysis can be conducted based
on any of the above-mentioned theories. The selection of a specific method is done by simply changing a few terms in a 2 by 2 square matrix and the results, obtained according to different plate theories, can be compared to
each other. Numerical examples are presented for piezoelectric composite plates subjected to mechanical loading.
The results based on different shear deformation theories are compared with the three-dimensional solutions. The behaviours of piezoelectric composite plates with different length-to-thickness ratios, fibre orientations, and
boundary conditions are also investigated in these examples.
|
토목공학
| null |
kci_detailed_000093.xml
|
|||
ART001375570
|
oai_dc
|
Adaptive tuned dynamic vibration absorbers working with MR elastomers
|
Adaptive tuned dynamic vibration absorbers working with MR elastomers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X. Z. Zhang(University of Wollongong); W. H. Li(University of Wollongong)"
] |
This paper presents the development of a new Adaptive Tuned Dynamic Vibration Absorber (ATDVA) working with magnetorheological elastomers (MREs). The MRE materials were fabricated by mixing carbonyl iron particles with silicone rubber and cured under a strong magnetic field. An ATDVA prototype using MRE as an adaptable spring was designed and manufactured. The MRE ATDVA worked in a shear mode and the magnetic field was generated by a magnetic circuit and controlled through a DC power supply. The dynamic performances or the system transmissibility at various magnetic fields of the absorber were measured by using a vibration testing system. Experimental results indicated that this absorber can change its natural frequency from 35Hz to 90Hz, 150% of its basic natural frequency. A real time control logic is proposed to evaluate the control effect. The simulation results indicate that the control effect of MRE ATDVA can be improved significantly.
|
토목공학
| null |
kci_detailed_000094.xml
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.