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|---|---|---|---|---|---|---|---|---|---|---|---|---|
ART001850185
|
oai_dc
|
Adaptive length SMA pendulum smart tuned mass damper performance in the presence of real time primary system stiffness change
|
Adaptive length SMA pendulum smart tuned mass damper performance in the presence of real time primary system stiffness change
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Satish Nagarajaiah(Rice University); Michael T. Contreras(California Institute of Technology); Dharma Theja Reddy Pasala(Rice University)"
] |
In a companion paper, Pasala and Nagarajaiah analytically and experimentally validate the Adaptive Length Pendulum Smart Tuned Mass Damper (ALP-STMD) on a primary structure (2 story steel structure) whose frequencies are time invariant (Pasala and Nagarajaiah 2012). In this paper, the ALP-STMD effectiveness on a primary structure whose frequencies are time varying is studied experimentally. This study experimentally validates the ability of an ALP-STMD to adequately control a structural system in the presence of real time changes in primary stiffness that are detected by a real time observer based system identification. The experiments implement the newly developed Adaptive Length Pendulum Smart Tuned Mass Damper (ALP-STMD) which was first introduced and developed by Nagarajaiah (2009), Nagarajaiah and Pasala (2010) and Nagarajaiah et al. (2010). The ALP-STMD employs a mass pendulum of variable length which can be tuned in real time to the parameters of the system using sensor feedback. The tuning action is made possible by applying a current to a shape memory alloy wire changing the effective length that supports the damper mass assembly in real time. Once a stiffness change in the structural system is detected by an open loop observer, the ALP-STMD is re-tuned to the modified system parameters which successfully reduce the response of the primary system. Significant performance improvement is illustrated for the stiffness modified system, which undergoes the re-tuning adaptation, when compared to the stiffness modified system without adaptive re-tuning.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850190
|
oai_dc
|
Active mass driver control system for suppressing wind-induced vibration of the Canton Tower
|
Active mass driver control system for suppressing wind-induced vibration of the Canton Tower
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Huai-bing Xu(Harbin Institute of Technology); Jin-ping Ou(Harbin Institute of Technology); Chun-wei Zhang(Harbin Institute of Technology); Hui Li(Harbin Institute of Technology); Ping Tan(Guangzhou University); Fu-lin Zhou(Guangzhou University)"
] |
In order to suppress the wind-induced vibrations of the Canton Tower, a pair of active mass river (AMD) systems has been installed on the top of the main structure. The structural principal directions n which the bending modes of the structure are uncoupled are proposed and verified based on the rthogonal projection approach. For the vibration control design in the principal X direction, the simplified odel of the structure is developed based on the finite element model and modified according to the field measurements under wind excitations. The AMD system driven by permanent magnet synchronous linear otors are adopted. The dynamical models of the AMD subsystems are determined according to the pen-loop test results by using nonlinear least square fitting method. The continuous variable gain feedback VGF) control strategy is adopted to make the AMD system adaptive to the variation in the intensity of wind excitations. Finally, the field tests of free vibration control are carried out. The field test results of AMD control show that the damping ratio of the first vibration mode increases up to 11 times of the original value without control.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850187
|
oai_dc
|
Design and implementation of AMD system for response control in tall buildings
|
Design and implementation of AMD system for response control in tall buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Teng(Harbin Instit. Technol. Shenzhen Graduate School); H.B. Xing(Harbin Instit. Technol. Shenzhen Graduate School); Y.Q. Xiao(Harbin Instit. Technol. Shenzhen Graduate School); C.Y. Liu(Harbin Instit. Technol. Shenzhen Graduate School); H. Li(Harbin Instit. Technol. Shenzhen Graduate School); J.P. Ou(Harbin Instit. Technol. Shenzhen Graduate School)"
] |
This paper mainly introduces recently developed technologies pertaining to the design and implementation of Active Mass Damper (AMD) control system on a high-rise building subjected to wind load. Discussions include introduction of real structure and the control system, the establishment of analytical model, the design and optimization of a variety of controllers, the design of time-varying variable gain feedback control strategy for limiting auxiliary mass stroke, and the design and optimization of AMD control devices. The results presented in this paper demonstrate that the proposed AMD control systems can resolve the issues pertaining to insufficient floor stiffness of the building. The control system operates well and has a good sensitivity.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850192
|
oai_dc
|
Active mass damper system using time delay control algorithm for building structure with unknown dynamics
|
Active mass damper system using time delay control algorithm for building structure with unknown dynamics
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"장동두(한국과학기술원); 정형조(한국과학기술원); Yeong-Jong Moon(Samsung C&T Corporation)"
] |
This paper numerically investigates the feasibility of an active mass damper (AMD) system using the time delay control (TDC) algorithm, which is one of the robust and adaptive control algorithms, for effectively suppressing the excessive vibration of a building structure under wind loading. Because of its several attractive features such as the simplicity and the excellent robustness to unknown system dynamics and disturbance, the TDC algorithm has the potential to be an effective control system for mitigating the vibration of civil engineering structures such as buildings and bridges. However, it has not been used for structural response reduction yet. In this study, therefore, the active control method combining an AMD system with the TDC algorithm is first proposed in order to reduce the wind-induced vibration of a building structure and its effectiveness is numerically examined. To this end, its stability analysis is first performed; and then, a series of numerical simulations are conducted. It is demonstrated that the proposed active structural control system can effectively reduce the acceleration response of the building structure.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850194
|
oai_dc
|
Family of smart tuned mass dampers with variable frequency under harmonic excitations and ground motions: closed-form evaluation
|
Family of smart tuned mass dampers with variable frequency under harmonic excitations and ground motions: closed-form evaluation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. Sun(Rice University); S. Nagarajaiah(Rice University); A.J. Dick(Rice University)"
] |
A family of smart tuned mass dampers (STMDs) with variable frequency and damping properties is analyzed under harmonic excitations and ground motions. Two types of STMDs are studied: one is realized by a semi-active independently variable stiffness (SAIVS) device and the other is realized by a pendulum with an adjustable length. Based on the feedback signal, the angle of the SAIVS device or the length of the pendulum is adjusted by using a servomotor such that the frequency of the STMD matches the dominant excitation frequency in real-time. Closed-form solutions are derived for the two types of STMDs under harmonic excitations and ground motions. Results indicate that a small damping ratio (zero damping is the best theoretically) and an appropriate mass ratio can produce significant reduction when compared to the case with no tuned mass damper. Experiments are conducted to verify the theoretical result of the smart pendulum TMD (SPTMD). Frequency tuning of the SPTMD is implemented through tracking and analyzing the signal of the excitation using a short time Fourier transformation (STFT) based control algorithm. It is found that the theoretical model can predict the structural responses well. Both the SAIVS STMD and the SPTMD can significantly attenuate the structural responses and outperform the conventional passive TMDs.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850179
|
oai_dc
|
A frequency tracking semi-active algorithm for control of edgewise vibrations in wind turbine blades
|
A frequency tracking semi-active algorithm for control of edgewise vibrations in wind turbine blades
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"John Arrigan(Trinity College Dublin); Chaojun Huang(Rice University); Andrea Staino(Trinity College Dublin); Satish Nagarajaiah(Rice University); Biswajit Basu(Trinity College Dublin)"
] |
With the increased size and flexibility of the tower and blades, structural vibrations are becoming a limiting factor towards the design of even larger and more powerful wind turbines. Research into the use of vibration mitigation devices in the turbine tower has been carried out but the use of dampers in the blades has yet to be investigated in detail. Mitigating vibrations will increase the design life and hence economic viability of the turbine blades and allow for continual operation with decreased downtime. The aim of this paper is to investigate the effectiveness of Semi-Active Tuned Mass Dampers (STMDs) in reducing the edgewise vibrations in the turbine blades. A frequency tracking algorithm based on the Short Time Fourier Transform (STFT) technique is used to tune the damper. A theoretical model has been developed to capture the dynamic behaviour of the blades including the coupling with the tower to accurately model the dynamics of the entire turbine structure. The resulting model consists of time dependent equations of motion and negative damping terms due to the coupling present in the system. The performances of the STMDs based vibration controller have been tested under different loading and operating conditions. Numerical analysis has shown that variation in certain parameters of the system, along with the time varying nature of the system matrices has led to the need for STMDs to allow for real-time tuning to the resonant frequencies of the system.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850182
|
oai_dc
|
Adaptive-length pendulum smart tuned mass damper using shape-memory-alloy wire for tuning period in real time
|
Adaptive-length pendulum smart tuned mass damper using shape-memory-alloy wire for tuning period in real time
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Satish Nagarajaiah(Rice University); Dharma Theja Reddy Pasala(Rice University)"
] |
Due to the shift in paradigm from passive control to adaptive control, smart tuned mass dampers (STMDs) have received considerable attention for vibration control in tall buildings and bridges. STMDs are superior to tuned mass dampers (TMDs) in reducing the response of the primary structure. Unlike TMDs, STMDs are capable of accommodating the changes in primary structure properties, due to damage or deterioration, by tuning in real time based on a local feedback. In this paper, a novel adaptive-length pendulum (ALP) damper is developed and experimentally verified. Length of the pendulum is adjusted in real time using a shape memory alloy (SMA) wire actuator. This can be achieved in two ways i) by changing the amount of current in the SMA wire actuator or ii) by changing the effective length of current carrying SMA wire. Using an instantaneous frequency tracking algorithm, the dominant frequency of the structure can be tracked from a local feedback signal, then the length of pendulum is adjusted to match the dominant frequency. Effectiveness of the proposed ALP-STMD mechanism, combined with the STFT frequency tracking control algorithm, is verified experimentally on a prototype two-storey shear frame. It has been observed through experimental studies that the ALP-STMD absorbs most of the input energy associated in the vicinity of tuned frequency of the pendulum damper. The reduction of storey displacements up to 80 % when subjected to forced excitation (harmonic and chirp-signal) and a faster decay rate during free vibration is observed in the experiments.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850189
|
oai_dc
|
Ambient modal identification of structures equipped with tuned mass dampers using parallel factor blind source separation
|
Ambient modal identification of structures equipped with tuned mass dampers using parallel factor blind source separation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Sadhu(University of Waterloo); B. Hazra(University of Waterloo); S. Narasimhan(University of Waterloo)"
] |
In this paper, a novel PARAllel FACtor (PARAFAC) decomposition based Blind Source Separation (BSS) algorithm is proposed for modal identification of structures equipped with tuned mass dampers. Tuned mass dampers (TMDs) are extremely effective vibration absorbers in tall flexible structures, but prone to get de-tuned due to accidental changes in structural properties, alteration in operating conditions, and incorrect design forecasts. Presence of closely spaced modes in structures coupled with TMDs renders output-only modal identification difficult. Over the last decade, second-order BSS algorithms have shown significant promise in the area of ambient modal identification. These methods employ joint diagonalization of covariance matrices of measurements to estimate the mixing matrix (mode shape coefficients) and sources (modal responses). Recently, PARAFAC BSS model has evolved as a powerful multi-linear algebra tool for decomposing an nth order tensor into a number of rank-1 tensors. This method is utilized in the context of modal identification in the present study. Covariance matrices of measurements at several lags are used to form a 3rd order tensor and then PARAFAC decomposition is employed to obtain the desired number of components, comprising of modal responses and the mixing matrix. The strong uniqueness properties of PARAFAC models enable direct source separation with fine spectral resolution even in cases where the number of sensor observations is less compared to the number of target modes, i.e., the underdetermined case. This capability is exploited to separate closely spaced modes of the TMDs using partial measurements, and subsequently to estimate modal parameters. The proposed method is validated using extensive numerical studies comprising of multi-degree-of-freedom simulation models equipped with TMDs, as well as with an experimental set-up.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001850174
|
oai_dc
|
Smart tuned mass dampers: recent developments
|
Smart tuned mass dampers: recent developments
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Satish Nagarajaiah(Rice University); 정형조(Korea Advanced Institute of Science and Technolog)"
] |
This special issue focuses on Smart Tuned Mass Dampers (STMD) that are either active or smart or semi-active in nature. Active tuned mass dampers or active mass dampers have found wide acceptance and have been implemented in many tall buildings and long span bridges. Recently researchers have developed a new class of smart tuned mass dampers using either variable stiffness and/or variable damping to effect the change in instantaneous frequency and damping. Since tuning plays a central role in STMDs it is of great current interest thus the topic of this special issue. Discussions of recent active and smart TMD implementations in tall buildings and bridges are also included.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846015
|
oai_dc
|
Application of shear deformation theory for two dimensional electro-elastic analysis of a FGP cylinder
|
Application of shear deformation theory for two dimensional electro-elastic analysis of a FGP cylinder
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Arefi(University of Kashan); G.H. Rahimi(Tarbiat Modares University)"
] |
The present study deals with two dimensional electro-elastic analysis of a functionally gradedpiezoelectric (FGP) cylinder under internal pressure. Energy method and first order shear deformationtheory (FSDT) are employed for this purpose. All mechanical and electrical properties except Poisson ratioare considered as a power function along the radial direction. The cylinder is subjected to uniform internalpressure. By supposing two dimensional displacement and electric potential fields along the radial and axialdirection, the governing differential equations can be derived in terms of unknown electrical and mechanicalfunctions. Homogeneous solution can be obtained by imposing the appropriate mechanical and electricalboundary conditions. This proposed solution has capability to solve the cylinder structure with arbitraryboundary conditions. The previous solutions have been proposed for the problem with simple boundaryconditions (simply supported cylinder) by using the routine functions such as trigonometric functions. Theaxial distribution of the axial displacement, radial displacement and electric potential of the cylinder can bepresented as the important results of this paper for various non homogeneous indexes. This paper evaluatesthe effect of a local support on the distribution of mechanical and electrical components. This investigationindicates that a support has important influence on the distribution of mechanical and electrical componentsrather than a cylinder with ignoring the effect of the supports. Obtained results using present method atregions that are adequate far from two ends of the cylinder can be compared with previous results (planeelasticity and one dimensional first order shear deformation theories).
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846021
|
oai_dc
|
Finite element modeling and bending analysis of piezoelectric sandwich beam with debonded actuators
|
Finite element modeling and bending analysis of piezoelectric sandwich beam with debonded actuators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. Venkata Rao(B.M.S Evening College of Engg.); S. Raja(CSIR-National Aerospace Laboratories); T. Munikenche Gowda(Principal, S.J.C. institute of Technology)"
] |
The present work pays emphasis on investigating the effect of different types of debonding on the bending behaviour of active sandwich beam, consisting of both extension and shear actuators. An active sandwich beam finite element is formulated by using Timoshenko’s beam theory, characterized by first order shear deformation for the core and Euler-Bernoulli’s beam theory for the top and bottom faces. The problemof debondings of extension actuator and face are dealt with by employing four-region model for inner debonding and three-region model for the edge debonding respectively. Displacement based continuity conditions are enforced at the interfaces of different regions using penalty method. Firstly, piezoelectric actuation of healthy sandwich beam is assessed through deflection analysis. Then the effect of actuators’ debondings with different boundary conditions on bending behavior is computationally evaluated and experimentally clamped-free case is validated. The results generated will be useful to address the damage tolerant design procedures for smart sandwich beam structures with structural control and health monitoring applications.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846018
|
oai_dc
|
Axisymmetric dynamic instability of polar orthotropic sandwich annular plate with ER damping treatment
|
Axisymmetric dynamic instability of polar orthotropic sandwich annular plate with ER damping treatment
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jia-Yi Yeh(Chung Hwa University of Medical Technology)"
] |
The axisymmetric dynamic instability of polar orthotropic sandwich annular plate combinedwith electrorheological (ER) fluid core layer and constraining layer are studied in this paper. And, the ERcore layer and constraining layer are used to improve the stability of the annular plate system. Theboundaries of instability regions for the polar orthotropic sandwich annular plate system are obtained bydiscrete layer annular finite element and the harmonic balance method. The rheological property of anelectrorheological material, such as viscosity, plasticity, and elasticity can be controlled by applying differentelectric field strength. Thus, the damping characteristics of the sandwich system are more effective when theelectric field is applied on the sandwich structure. Additionally, variations of the instability regions for thepolar orthotropic sandwich annular plate with different applying electric field strength, thickness of ER layerand some designed parameters are investigated and discussed in this study.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846020
|
oai_dc
|
Feasibility study on corrosion monitoring of a concrete column with central rebar using BOTDR
|
Feasibility study on corrosion monitoring of a concrete column with central rebar using BOTDR
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yijie Sun(Nanjing University); Bin Shi(Nanjing University); Shen-en Chen(University of North Carolina); Honghu Zhu(Nanjing University); Dan Zhang(Nanjing University); Yi Lu(Nanjing University)"
] |
Optical fiber Brillouin sensor in a coil winding setup is proposed in this paper to measure the expansion deformation of a concrete column with a central rebar subjected to accelerated corrosion. The optical sensor monitored the whole dynamic corrosion process from initial deformation to final cracking. Experimental results show that Brillouin Optical Time Domain Reflectometer (BOTDR) can accurately measure the strain values and identify the crack locations of the simulated reinforced concrete (RC) column.
A theoretical model is used to calculate the RC corrosion expansive pressure and crack length. The results indicate that the measured strain and cracking history revealed the development of the steel bar corrosion inside the simulated RC column.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846085
|
oai_dc
|
3D buckling analysis of FGM sandwich plates under bi-axial compressive loads
|
3D buckling analysis of FGM sandwich plates under bi-axial compressive loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chih-Ping Wu(National Cheng Kung University); Wei-Lun Liu(National Cheng Kung University)"
] |
Based on the Reissner mixed variational theorem (RMVT), finite rectangular layer methods (FRLMs) are developed for the three-dimensional (3D) linear buckling analysis of simply-supported, fiber-reinforced composite material (FRCM) and functionally graded material (FGM) sandwich plates subjected to bi-axial compressive loads. In this work, the material properties of the FGM layers are assumed to obey the power-law distributions of the volume fractions of the constituents through the thickness, and theplate is divided into a number of finite rectangular layers, in which the trigonometric functions and Lagrange polynomials are used to interpolate the in- and out-of-plane variations of the field variables of each individual layer, respectively, and an h-refinement process is adopted to yield the convergent solutions. The accuracy and convergence of the RMVT-based FRLMs with various orders used for expansions of eachfield variables through the thickness are assessed by comparing their solutions with the exact 3D and accurate two-dimensional ones available in the literature.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846086
|
oai_dc
|
Experimental identification of the six DOF C.G.S., Algeria, shaking table system
|
Experimental identification of the six DOF C.G.S., Algeria, shaking table system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Abdelhalim Airouche(National Earthquake Engineering Research Center); Hakim Bechtoula(National Earthquake Engineering Research Center); Hassan Aknouche(National Earthquake Engineering Research Center); Bradford K.Thoen(MTS Systems Corporation); Djillali Benouar(University of Bab Ezzouar (USTHB))"
] |
Servohydraulic shaking tables are being increasingly used in the field of earthquake engineering. They play a critical role in the advancement of the research state and remain one of the valuable tools for seismic testing. Recently, the National Earthquake Engineering Research Center, CGS, has acquired a 6.1m x 6.1 m shaking table system which has a six degree-of-freedom testing capability. The maximum specimenmass that can be tested on the shaking table is 60 t. This facility is designed specially for testing a complete civil engineering structures, substructures and structural elements up to collapse or ultimate limit states. It can also be used for qualification testing of industrial equipments. The current paper presents the main findings of the experimental shake-down characterization testing of the CGS shaking table. The test programcarried out in this study included random white noise and harmonic tests. These tests were performed along each of the six degrees of freedom, three translations and three rotations. This investigation provides fundamental parameters that are required and essential while elaborating a realistic model of the CGS shaking table. Also presented in this paper, is the numerical model of the shaking table that was establishedand validated.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846022
|
oai_dc
|
Predicting the buckling load of smart multilayer columns using soft computing tools
|
Predicting the buckling load of smart multilayer columns using soft computing tools
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yaser Shahbazi(Tabriz Islamic Art University); Ehsan Delavari(Sahand University of Technology); Mohammad Reza Chenaghlou(Sahand University of Technology)"
] |
This paper presents the elastic buckling of smart lightweight column structures integrated with a pair of surface piezoelectric layers using artificial intelligence. The finite element modeling of Smart lightweight columns is found using ANSYS® software. Then, the first buckling load of the structure is calculated using eigenvalue buckling analysis. To determine the accuracy of the present finite element analysis, a compression study is carried out with literature. Later, parametric studies for length variations,width, and thickness of the elastic core and of the piezoelectric outer layers are performed and the associated buckling load data sets for artificial intelligence are gathered. Finally, the application of soft computing-based methods including artificial neural network (ANN), fuzzy inference system (FIS), and adaptive neuro fuzzy inference system (ANFIS) were carried out. A comparative study is then made between the mentioned soft computing methods and the performance of the models is evaluated using statistic measurements. The comparison of the results reveal that, the ANFIS model with Gaussian membership function provides high accuracy on the prediction of the buckling load in smart lightweight columns, providing better predictions compared to other methods. However, the results obtained from the ANN model using the feed-forward algorithm are also accurate and reliable.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846084
|
oai_dc
|
Quantity vs. Quality in the Model Order Reduction (MOR) of a Linear System
|
Quantity vs. Quality in the Model Order Reduction (MOR) of a Linear System
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lucia Faravelli(University of Pavia); Sara Casciati(University of Catania)"
] |
The goal of any Model Order Reduction (MOR) technique is to build a model of order lower than the one of the real model, so that the computational effort is reduced, and the ability to estimate the input-output mapping of the original system is preserved in an important region of the input space. Actually, since only a subset of the input space is of interest, the matching is required only in this subset of the input space. In this contribution, the consequences on the achieved accuracy of adopting different reduction technique patterns is discussed mainly with reference to a linear case study.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001846088
|
oai_dc
|
Crack source location by acoustic emission monitoring method in RC strips during in-situ load test
|
Crack source location by acoustic emission monitoring method in RC strips during in-situ load test
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tala Shokri(University of Miami); Antonio Nanni(University of Miami)"
] |
Various monitoring techniques are now available for structural health monitoring and Acoustic Emission (AE) is one of them. One of the major advantages of the AE technique is its capability to locate active cracks in structural members. AE crack locating approaches are affected by the signal attenuation and dispersion of elastic waves due to inhomogeneity and geometry of reinforced concrete (RC) members. In this paper, a novel technique is described based on signal processing and sensor arrangement to process multisensory AE data generated by the onset and propagation of cracks and is validated with experimental results from an in-situ load test. Considering the sources of uncertainty in the AE crack location process, a methodology is proposed to capture and locate events generated by cracks. In particular, the relationship between AE events and load is analyzed, and the feasibility of using the AE technique to evaluate the cracking behavior of two RC slab strips during loading to failure is studied.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739913
|
oai_dc
|
Application of recursive SSA as data pre-processing filter for stochastic subspace identification
|
Application of recursive SSA as data pre-processing filter for stochastic subspace identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chin-Hsiung Loh(National Taiwan University); Yi-Cheng Liu(National Taiwan University)"
] |
The objective of this paper is to develop on-line system parameter estimation and damage detection technique from the response measurements through using the Recursive Covariance-Driven Stochastic Subspace identification (RSSI-COV) approach. To reduce the effect of noise on the results of identification, discussion on the pre-processing of data using recursive singular spectrum analysis (rSSA) is presented to remove the noise contaminant measurements so as to enhance the stability of data analysis.
Through the application of rSSA-SSI-COV to the vibration measurement of bridge during scouring experiment, the ability of the proposed algorithm was proved to be robust to the noise perturbations and offers a very good online tracking capability. The accuracy and robustness offered by rSSA-SSI-COV provides a key to obtain the evidence of imminent bridge settlement and a very stable modal frequency tracking which makes it possible for early warning. The peak values of the identified 1st mode shape slope ratio has shown to be a good indicator for damage location, meanwhile, the drastic movements of the peak of 2nd mode slope ratio could be used as another feature to indicate imminent pier settlement.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739923
|
oai_dc
|
Particle filter for model updating and reliability estimation of existing structures
|
Particle filter for model updating and reliability estimation of existing structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ikumasa Yoshida(Tokyo City University); Mitsuyoshi Akiyama(Waseda University)"
] |
It is essential to update the model with reflecting observation or inspection data for reliability estimation of existing structures. Authors proposed updated reliability analysis by using Particle Filter. We discuss how to apply the proposed method through numerical examples on reinforced concrete structures after verification of the method with hypothetical linear Gaussian problem. Reinforced concrete structures in a marine environment deteriorate with time due to chloride-induced corrosion of reinforcing bars. In the case of existing structures, it is essential to monitor the current condition such as chloride-induced corrosion and to reflect it to rational maintenance with consideration of the uncertainty. In this context, updated reliability estimation of a structure provides useful information for the rational decision. Accuracy estimation is also one of the important issues when Monte Carlo approach such as Particle Filter is adopted. Especially Particle Filter approach has a problem known as degeneracy. Effective sample size is introduced to predict the covariance of variance of limit state exceeding probabilities calculated by Particle Filter. Its validity is shown by the numerical experiments.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739919
|
oai_dc
|
Multi-stage approach for structural damage identification using particle swarm optimization
|
Multi-stage approach for structural damage identification using particle swarm optimization
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"H. Tang(Tongji University); W. Zhang(2Fujian Academy of Building Research); L. Xie(Tongji University); S. Xue(Tongji University,Tohoku Institute of Technology)"
] |
An efficient methodology using static test data and changes in natural frequencies is proposed to identify the damages in structural systems. The methodology consists of two main stages. In the first stage, the Damage Signal Match (DSM) technique is employed to quickly identify the most potentially damaged elements so as to reduce the number of the solution space (solution parameters). In the second stage, a particle swarm optimization (PSO) approach is presented to accurately determine the actual damage extents using the first stage results. One numerical case study by using a planar truss and one experimental case study by using a full-scale steel truss structure are used to verify the proposed hybrid method. The identification results show that the proposed methodology can identify the location and severity of damage with a reasonable level of accuracy, even when practical considerations limit the number of measurements to only a few for a complex structure.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739917
|
oai_dc
|
Particle relaxation method for structural parameters identification based on Monte Carlo Filter
|
Particle relaxation method for structural parameters identification based on Monte Carlo Filter
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tadanobu Sato(Southeast University); Youhei Tanaka(Minicipality of Nishinomiya)"
] |
In this paper we apply Monte Carlo Filter to identifying dynamic parameters of structural systems and improve the efficiency of this algorithm. The algorithms using Monte Carlo Filter so far has not been practical to apply to structural identification for large scale structural systems because computation time increases exponentially as the degrees of freedom of the system increase. To overcome this problem, we developed a method being able to reduce number of particles which express possible structural response state vector. In MCF there are two steps which are the prediction and filtering processes. The idea is very simple. The prediction process remains intact but the filtering process is conducted at each node of structural system in the proposed method. We named this algorithm as relaxation Monte Carlo Filter (RMCF) and demonstrate its efficiency to identify large degree of freedom systems. Moreover to increase searching field and speed up convergence time of structural parameters we proposed an algorithm combining the Genetic Algorithm with RMCF and named GARMCF. Using shaking table test data of a model structure we also demonstrate the efficiency of proposed algorithm.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739911
|
oai_dc
|
Linear system parameter as an indicator for structural diagnosis of short span bridges
|
Linear system parameter as an indicator for structural diagnosis of short span bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김철우(Kyoto University); Ryo Isemoto(Kyoto University); Kunitomo Sugiura(Kyoto University); Mitsuo Kawatani(Kobe University)"
] |
This paper intended to investigate the feasibility of bridge health monitoring using a linear system parameter of a time series model identified from traffic-induced vibrations of bridges through a laboratory moving vehicle experiment on scaled model bridges. This study considered the system parameter of the bridge-vehicle interactive system rather than modal ones because signals obtained under a moving vehicle are not the responses of the bridge itself but those of the interactive system. To overcome the shortcomings of modal parameter-based bridge diagnosis using a time series model, this study considered coefficients of Autoregressive model (AR coefficients) as an early indicator of anomaly of bridges. This study also investigated sensitivity of AR coefficients in detecting anomaly of bridges. Observations demonstrated effectiveness of using AR coefficients as an early indicator for anomaly of bridges.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739916
|
oai_dc
|
Some precautions to consider in using wavelet transformation for damage detection analysis of plates
|
Some precautions to consider in using wavelet transformation for damage detection analysis of plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.B. Beheshti-Aval(K.N. Toosi University of Technology); M. Taherinasab(Jundi-Shapur University of Technology); M. Noori(California Polytechnic State University)"
] |
Over the last two decades Wavelet Transformation (WT) method has been widely utilized for the damage identification of structures. The main objective of this paper is to discuss and present some of common shortcomings and limitations of mathematical software, as well as other precautionary measures that need to be considered when using them for wavelet analysis applications. Due to popular usage of MATLAB® comparing to other mathematical tools among researchers for data processing of structural responses through WT analysis, this software was chosen for specific study. To the best of the authors’ knowledge, these limitations and observations have not been previously identified or discussed in the literature. In this work, a square plate with a severe damage, in form of a crack, parallel to the left edge of the plate is selected for a pilot study. The steady state harmonic response is used for measuring the deflection shape across the line parallel to one edge and perpendicular to the damage. Several criteria and cases such as the smallest size damage that can be detected, correlation between the crack width and the number of sampling points, and the influence of the damage thickness on the accuracy of the result are investigated.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739925
|
oai_dc
|
Structural modal identification through ensemble empirical modal decomposition
|
Structural modal identification through ensemble empirical modal decomposition
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Zhang(Southeast University); R.Q. Yan(Southeast University); C.Q. Yang(Southeast University)"
] |
Identifying structural modal parameters, especially those modes within high frequency range, from ambient data is still a challenging problem due to various kinds of uncertainty involved in vibration measurements. A procedure applying an ensemble empirical mode decomposition (EEMD) method is proposed for accurate and robust structural modal identification. In the proposed method, the EEMD process is first implemented to decompose the original ambient data to a set of intrinsic mode functions (IMFs),which are zero-mean time series with energy in narrow frequency bands. Subsequently, a Sub-PolyMAX method is performed in narrow frequency bands by using IMFs as primary data for structural modal identification. The merit of the proposed method is that it performs structural identification in narrow frequency bands (take IMFs as primary data), unlike the traditional method in the whole frequency space (take original measurements as primary data), thus it produces more accurate identification results. A numerical example and a multiple-span continuous steel bridge have been investigated to verify the effectiveness of the proposed method.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001739921
|
oai_dc
|
Damage identification using chaotic excitation
|
Damage identification using chaotic excitation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chunfeng Wan(Southeast University); Tadanobu Sato(Southeast University); Zhishen Wu(Southeast University); Jian Zhang(Southeast University)"
] |
Vibration-based damage detection methods are popular for structural health monitoring. However, they can only detect fairly large damages. Usually impact pulse, ambient vibrations and sine-wave forces are applied as the excitations. In this paper, we propose the method to use the chaotic excitation to vibrate structures. The attractors built from the output responses are used for the minor damage detection. After the damage is detected, it is further quantified using the Kalman Filter. Simulations are conducted. A 5-story building is subjected to chaotic excitation. The structural responses and related attractors are analyzed. The results show that the attractor distances increase monotonously with the increase of the damage degree.
Therefore, damages, including minor damages, can be effectively detected using the proposed approach. With the Kalman Filter, damage which has the stiffness decrease of about 5% or lower can be quantified. The proposed approach will be helpful for detecting and evaluating minor damages at the early stage.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802551
|
oai_dc
|
Online damage detection using pair cointegration method of time-varying displacement
|
Online damage detection using pair cointegration method of time-varying displacement
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cui Zhou(Dalian University of Technology); Hong-Nan Li(Dalian University of Technology); Dong-Sheng Li(Dalian University of Technology); You-Xin Lin(Guangdong Electrical Company); Ting-Hua Yi(Dalian University of Technology)"
] |
Environmental and operational variables are inevitable concerns by researchers and engineers when implementing the damage detection algorithm in practical projects, because the change of structural behavior could be masked by the conditions in a large extent. Thus, reliable damage detection methods should have a virtue of immunity from environmental and operational variables. In this paper, the pair cointegration method was presented as a novel way to remove the effect of environmental variables. At the beginning, the concept and procedure of this approach were introduced, and then the theoretical formulation and numerical simulations were put forward to illustrate the feasibility. The jump exceeding the control limit in the residual indicates the occurrence of damage, while the direction and magnitude imply the most potential damage location. In addition, the simulation results show that the proposed method has strong ability to resist the noise.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802542
|
oai_dc
|
Diagnosis and recovering on spatially distributed acceleration using consensus data fusion
|
Diagnosis and recovering on spatially distributed acceleration using consensus data fusion
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wei Lu(Harbin Institute of Technology Shenzhen Graduate School); Jun Teng(Harbin Institute of Technology Shenzhen Graduate S); Yanhuang Zhu(Harbin Institute of Technology Shenzhen Graduate School)"
] |
The acceleration information is significant for the structural health monitoring, which is the basic measurement to identify structural dynamic characteristics and structural vibration. The efficiency of the accelerometer is subsequently important for the structural health monitoring. In this paper, the distance measure matrix and the support level matrix are constructed firstly and the synthesized support level and the fusion method are given subsequently. Furthermore, the synthesized support level can be served as the determination for diagnosis on accelerometers, while the consensus data fusion method can be used to recover the acceleration information in frequency domain. The acceleration acquisition measurements from the accelerometers located on the real structure National Aquatics Center are used to be the basic simulation data here. By calculating two groups of accelerometers, the validation and stability of diagnosis and recovering on acceleration based on the data fusion are proofed in the paper.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802565
|
oai_dc
|
Multi-stage structural damage diagnosis method based on “energy-damage” theory
|
Multi-stage structural damage diagnosis method based on “energy-damage” theory
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology); Hong-Nan Li(Dalian University of Technology); Hong-Min Sun(Shenyang Jianzhu University)"
] |
Locating and assessing the severity of damage in large or complex structures is one of the most challenging problems in the field of civil engineering. Considering that the wavelet packet transform (WPT) has the ability to clearly reflect the damage characteristics of structural response signals and the artificial neural network (ANN) is capable of learning in an unsupervised manner and of forming new classes when the structural exhibits change, this paper investigates a multi-stage structural damage diagnosis method by using the WPT and ANN based on “energy-damage” theory, in which, the wavelet packet component energies are first extracted to be damage sensitive feature and then adopted as input into an improved back propagation (BP) neural network model for damage diagnosis in a step by step mode. To validate the efficacy of the presented approach of the damage diagnosis, the benchmark structure of the American Society of Civil Engineers (ASCE) is employed in the case study. The results of damage diagnosis indicate that the method herein is computationally efficient and is able to detect the existence of different damage patterns in the simulated experiment where minor, moderate and severe damages corresponds to involving in the loss of stiffness on braces or the removal bracing in various combinations.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802558
|
oai_dc
|
Theoretical and experimental study on damage detection for beam string structure
|
Theoretical and experimental study on damage detection for beam string structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Haoxiang He(Beijing University of Technology); Weiming Yan(Beijing University of Technology); Ailin Zhang(Beijing University of Technology)"
] |
Beam string structure (BSS) is introduced as a new type of hybrid prestressed string structures. The composition and mechanics features of BSS are discussed. The main principles of wavelet packet transform (WPT), principal component analysis (PCA) and support vector machine (SVM) have been reviewed. WPT is applied to the structural response signals, and feature vectors are obtained by feature extraction and PCA. The feature vectors are used for training and classification as the inputs of the support vector machine. The method is used to a single one-way arched beam string structure for damage detection. The cable prestress loss and web members damage experiment for a beam string structure is carried through. Different prestressing forces are applied on the cable to simulate cable prestress loss, the prestressing forces are calculated by the frequencies which are solved by Fourier transform or wavelet transform under impulse excitation. Test results verify this method is accurate and convenient. The damage cases of web members on the beam are tested to validate the efficiency of the method presented in this study. Wavelet packet decomposition is applied to the structural response signals under ambient vibration, feature vectors are obtained by feature extraction method. The feature vectors are used for training and classification as the inputs of the support vector machine. The structural damage position and degree can be identified and classified, and the test result is highly accurate especially combined with principle component analysis.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802539
|
oai_dc
|
GPS/RTS data fusion to overcome signal deficiencies in certain bridge dynamic monitoring projects
|
GPS/RTS data fusion to overcome signal deficiencies in certain bridge dynamic monitoring projects
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fanis Moschas(University of Patras); Panos A. Psimoulis(ETH Zurich); Stathis C. Stiros(University of Patras)"
] |
Measurement of deflections of certain bridges is usually hampered by corruption of the GPS signal by multipath associated with passing vehicles, resulting to unrealistically large apparent displacements. Field data from the Gorgopotamos train bridge in Greece and systematic experiments revealed that such bias is due to superimposition of two major effects, (i) changes in the geometry of satellites because of partial masking of certain satellites by the passing vehicles (this effect can be faced with solutions excluding satellites that get temporarily blocked by passing vehicles) and (ii) dynamic multipath caused from reflection of satellite signals on the passing trains, a high frequency multipath effect, different from the static multipath. Dynamic multipath seems to have rather irregular amplitude, depending on the geometry of measured satellites, but a typical pattern, mainly consisting of a baseline offset, wide base peaks correlating with the sequence of main reflective surfaces of the vehicles passing next to the antenna. In cases of limited corruption of GPS signal by dynamic multipath, corresponding to scale distortion of the short-period component of the GPS waveforms, we propose an algorithm which permits to reconstruct the waveform of bridge deflections using a weak fusion of GPS and RTS data, based on the complementary characteristics of the two instruments. By application of the proposed algorithm we managed to extract semi-static and dynamic displacements and oscillation frequencies of a historical railway bridge under train loading by using noisy GPS and RTS recordings. The combination of GPS and RTS is possible because these two sensors can be fully collocated and have complementary characteristics, with RTS and GPS focusing on the long- and short-period characteristics of the displacement, respectively.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802544
|
oai_dc
|
A novel transmissibility concept based on wavelet transform for structural damage detection
|
A novel transmissibility concept based on wavelet transform for structural damage detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhe Fan(Dalian University of Technology); Xin Feng(Dalian University of Technology); Jing Zhou(Dalian University of Technology)"
] |
A novel concept of transmissibility based on a wavelet transform for structural damage detection is presented in this paper. The main objective of the research was the development of a method for detecting slight damage at the incipient stage. As a vibration-based approach, the concept of transmissibility has attracted considerable interest because of its advantages and effectiveness in damage detection. However, like other vibration-based methods, transmissibility-based approaches suffer from insensitivity to slight local damage because of the regularity of the traditional Fourier transform. Therefore, the powerful signal processing techniques must be found to solve this problem. Wavelet transform that is able to capture subtle information in measured signals has received extensive attention in the field of damage detection in recent decades. In this paper, we first propose a novel transmissibility concept based on the wavelet transform. Outlier analysis was adopted to construct a damage detection algorithm with wavelet-based transmissibility. The feasibility of the proposed method was numerically investigated with a typical six-degrees-of-freedom spring-mass system, and comparative investigations were performed with a conventional transmissibility approach. The results demonstrate that the proposed transmissibility is more sensitive than conventional transmissibility, and the former is a promising tool for structural damage detection at the incipient stage.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001802535
|
oai_dc
|
Multi-dimensional sensor placement optimization for Canton Tower focusing on application demands
|
Multi-dimensional sensor placement optimization for Canton Tower focusing on application demands
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology); Hong-Nan Li(Dalian University of Technology); Xiang Wang(Dalian University of Technology)"
] |
Optimal sensor placement (OSP) technique plays a key role in the structural health monitoring (SHM) of large-scale structures. According to the mathematical background and implicit assumptions made in the triaxial effective independence (EfI) method, this paper presents a novel multi-dimensional OSP method for the Canton Tower focusing on application demands. In contrast to existing methods, the presented method renders the corresponding target mode shape partitions as linearly independent as possible and, at the same time, maintains the stability of the modal matrix in the iteration process. The modal assurance criterion (MAC), determinant of the Fisher Information Matrix (FIM) and condition number of the FIM have been taken as the optimal criteria, respectively, to demonstrate the feasibility and effectiveness of the proposed method. Numerical investigations suggest that the proposed method outperforms the original EfI method in all instances as expected, which is looked forward to be even more pronounced should it be used for other multi-dimensional optimization problems.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001750964
|
oai_dc
|
Numerical characterizations of a piezoelectric micromotor using topology optimization design
|
Numerical characterizations of a piezoelectric micromotor using topology optimization design
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Sadeghbeigi Olyaie(Amirkabir University of Technology); M.R. Razfar(Amirkabir University of Technology)"
] |
This paper presents the optimum load-speed diagram evaluation for a linear micromotor, including multitude cantilever piezoelectric bimorphs, briefly. Each microbeam in the mechanism can be actuated in both axial and flexural modes simultaneously. For this design, we consider quasi-static and linear conditions, and a relatively new numerical method called the smoothed finite element method (S-FEM) is introduced here. For this purpose, after finding an optimum volume fraction for piezoelectric layers through a standard numerical method such as quadratic finite element method, the relevant load-speed curves of the optimized micromotor are examined and compared by deterministic topology optimization (DTO) design. In this regard, to avoid the overly stiff behavior in FEM modeling, a numerical method known as the cell-based smoothed finite element method (CS-FEM, as a branch of S-FEM) is applied for our DTO problem. The topology optimization procedure to find the optimal design is implemented using a solid isotropic material with a penalization (SIMP) approximation and a method of moving asymptotes (MMA) optimizer. Because of the higher efficiency and accuracy of S-FEMs with respect to standard FEMs, the main micromotor characteristics of our final DTO design using a softer CS-FEM are substantially improved.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001750965
|
oai_dc
|
A multi-radio sink node designed for wireless SHM applications
|
A multi-radio sink node designed for wireless SHM applications
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shenfang Yuan(Nanjing University of Aeronautics and Astronautics); Zilong Wang(Nanjing University of Aeronautics and Astronautics); Lei Qiu(Nanjing University of Aeronautics and Astronautics); Yang Wang(Nanjing University of Aeronautics and Astronautics); Menglong Liu(Nanjing University of Aeronautics and Astronautics)"
] |
Structural health monitoring (SHM) is an application area of Wireless Sensor Networks (WSNs) which usually needs high data communication rate to transfer a large amount of monitoring data. Traditional sink node can only process data from one communication channel at the same time because of the single radio chip structure. The sink node constitutes a bottleneck for constructing a high data rate SHM application giving rise to a long data transfer time. Multi-channel communication has been proved to be an efficient method to improve the data throughput by enabling parallel transmissions among different frequency channels. This paper proposes an 8-radio integrated sink node design method based on Field Programmable Gate Array (FPGA) and the time synchronization mechanism for the multi-channel network based on the proposed sink node. Three experiments have been performed to evaluate the data transfer ability of the developed multi-radio sink node and the performance of the time synchronization mechanism. A high data throughput of 1020Kbps of the developed sink node has been proved by experiments using IEEE.805.15.4.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001750967
|
oai_dc
|
Recurrence plot entropy for machine defect severity assessment
|
Recurrence plot entropy for machine defect severity assessment
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ruqiang Yan(Southeast University); Yuning Qian(Southeast University); Zhoudi Huang(Southeast University); Robert X. Gao(University of Connecticut)"
] |
This paper presents a nonlinear time series analysis technique for evaluating machine defect severity, based on the Recurrence Plot (RP) entropy. The RP entropy is calculated from the probability distribution of the diagonal line length in the recurrence plot, which graphically depicts a system’s dynamics and provides a global picture of the autocorrelation in a time series over all available time-scales. Results of experimental studies conducted on a spindle-bearing test bed have demonstrated that, as the working condition of the bearing deteriorates due to the initiation and/or progression of structural damages, the frequency information contained in the vibration signal becomes increasingly complex, leading to the increase of the RP entropy. As a result, RP entropy can serve as an effective indicator for defect severity assessment of rolling bearings.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001750966
|
oai_dc
|
Design and testing of a minimally invasive intervertebral cage for spinal fusion surgery
|
Design and testing of a minimally invasive intervertebral cage for spinal fusion surgery
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Walter Anderson(University of Toledo); Cory Chapman(University of Toledo); Zohreh Karbaschi(University of Toledo); Mohammad Elahinia(University of Toledo); Vijay Goel(University of Toledo)"
] |
An innovative cage for spinal fusion surgery is presented within this work. The cage utilizes shape memory alloy for its hinge actuation. Because of the use of SMA, a smaller incision is needed which makes the cage deployment minimally invasive. In the development of the cage, a model for predicting the torsional behavior of SMAs was developed and verified experimentally. The prototype design of the cage was developed and manufactured. The prototype was subjected to static tests per ASTM specifications. The cage survived all of the tests, alluding to its safety within the body.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001750968
|
oai_dc
|
A nonlinear structural experiment platform with adjustable plastic hinges: analysis and vibration control
|
A nonlinear structural experiment platform with adjustable plastic hinges: analysis and vibration control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Luyu Li(University of Houston); Gangbing Song(University of Houston); Jinping Ou(Dalian University of Technology)"
] |
The construction of an experimental nonlinear structural model with little cost and unlimited repeatability for vibration control study represents a challenging task, especially for material nonlinearity. This paper reports the design, analysis and vibration control of a nonlinear structural experiment platform with adjustable hinges. In our approach, magnetorheological rotary brakes are substituted for the joints of a frame structure to simulate the nonlinear material behaviors of plastic hinges. For vibration control, a separate magnetorheological damper was employed to provide semi-active damping force to the nonlinear structure. A dynamic neural network was designed as a state observer to enable the feedback based semi-active vibration control. Based on the dynamic neural network observer, an adaptive fuzzy sliding mode based output control was developed for the magnetorheological damper to suppress the vibrations of the structure. The performance of the intelligent control algorithm was studied by subjecting the structure to shake table experiments. Experimental results show that the magnetorheological rotary brake can simulate the nonlinearity of the structural model with good repeatability. Moreover, different nonlinear behaviors can be achieved by controlling the input voltage of magnetorheological rotary damper. Different levels of nonlinearity in the vibration response of the structure can be achieved with the above adaptive fuzzy sliding mode control algorithm using a dynamic neural network observer.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826624
|
oai_dc
|
Vibration based damage localization using MEMS on a suspension bridge model
|
Vibration based damage localization using MEMS on a suspension bridge model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marco Domaneschi(DICA); Maria Pina Limongelli(ABC); Luca Martinelli(DICA)"
] |
In this paper the application of the Interpolation Damage Detection Method to the numerical model of a suspension bridge instrumented with a network of Micro-Electro-Mechanical System sensors is presented. The method, which, in its present formulation, belongs to Level II damage identification method, can identify the presence and the location of damage from responses recorded on the structure before and after a seismic damaging event. The application of the method does not require knowledge of the modal properties of the structure nor a numerical model of it. Emphasis is placed herein on the influence of recorded signals noise on the reliability of the results given by the Interpolation Damage Detection Method. The response of a suspension bridge to seismic excitation is computed from a numerical model and artificially corrupted with random noise characteristic of two families of Micro-Electro-Mechanical System accelerometers. The reliability of the results is checked for different damage scenarios.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826620
|
oai_dc
|
Bridge load testing and rating: a case study through wireless sensing technology
|
Bridge load testing and rating: a case study through wireless sensing technology
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Samir N. Shoukry(West Virginia University); Yan Luo(DEI Group); Mourad Y. Riad(West Virginia University); Gergis W. William(West Virginia University)"
] |
In this paper, a wireless sensing system for structural field evaluation and rating of bridges is presented. The system uses a wireless platform integrated with traditional analogue sensors including strain gages and accelerometers along with the operating software. A wireless vehicle position indicator is developed using a tri-axial accelerometer node that is mounted on the test vehicle, and was used for identifying the moving truck position during load testing. The developed software is capable of calculating the theoretical bridge rating factors based on AASHTO Load and Resistance Factor Rating specifications, and automatically produces the field adjustment factor through load testing data. The sensing system along with its application in bridge deck rating was successfully demonstrated on the Evansville Bridge in West Virginia. A finite element model was conducted for the test bridge, and was used to calculate the load distribution factors of the bridge deck after verifying its results using field data. A confirmation field test was conducted on the same bridge and its results varied by only 3% from the first test. The proposed wireless sensing system proved to be a reliable tool that overcomes multiple drawbacks of conventional wired sensing platforms designed for structural load evaluation of bridges.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826626
|
oai_dc
|
Damping updating of a building structure installed with an MR damper
|
Damping updating of a building structure installed with an MR damper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"우성식(단국대학교); 이상현(단국대학교)"
] |
The purpose of this paper is to identify through experiments the finite element (FE) model of a building structure using a magnetorheological (MR) fluid damper. The FE model based system identification (FEBSI) technique evaluates the control performance of an MR damper that has nonlinear characteristics as equivalent linear properties such as mass, stiffness, and damping. The Bingham and Bouc-Wen models were used for modeling the MR damper and the equivalent damping increased by the MR damper was predicted by applying an equivalent linearization technique. Experimental results indicate that the predicted equivalent damping matches well with the experimentally obtained damping.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826587
|
oai_dc
|
Substructure based structural damage detection with limited input and output measurements
|
Substructure based structural damage detection with limited input and output measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. Lei(Xiamen University); C. Liu(Xiamen University); Y.Q. Jiang(Xiamen University); Y.K. Mao(Xiamen University)"
] |
It is highly desirable to explore efficient algorithms for detecting structural damage of large size structural systems with limited input and output measurements. In this paper, a new structural damage detection algorithm based on substructure approach is proposed for large size structural systems with limited input and output measurements. Inter-connection effect between adjacent substructures is treated as „additional unknown inputs‟ to substructures. Extended state vector of each substructure and its unknown excitations are estimated by sequential extended Kalman estimator and least-squares estimation, respectively. It is shown that the „additional unknown inputs‟ can be estimated by the algorithm without the measurements on the substructure interface DOFs, which is superior to previous substructural identification approaches. Also, structural parameters and unknown excitation are estimated in a sequential manner, which simplifies the identification problem compared with other existing work. Structural damage can be detected from the degradation of the identified substructural element stiffness values. The performances of the proposed algorithm are demonstrated by several numerical examples and a lab experiment. Measurement noise effect is considered. Both the simulation results and experimental data validate that the proposed algorithm is viable for structural damage detection of large size structural systems with limited input and output measurements.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826589
|
oai_dc
|
Robust optimization of a hybrid control system for wind-exposed tall buildings with uncertain mass distribution
|
Robust optimization of a hybrid control system for wind-exposed tall buildings with uncertain mass distribution
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ilaria Venanzi(University of Perugia); Annibale Luigi Materazzi(University of Perugia)"
] |
In this paper is studied the influence of the uncertain mass distribution over the floors on the choice of the optimal parameters of a hybrid control system for tall buildings subjected to wind load. In particular, an optimization procedure is developed for the robust design of a hybrid control system that is based on an enhanced Monte Carlo simulation technique and the genetic algorithm. The large computational effort inherent in the use of a MC-based procedure is reduced by the employment of the Latin Hypercube Sampling. With reference to a tall building modeled as a multi degrees of freedom system, several numerical analyses are carried out varying the parameters influencing the floors’ masses, like the coefficient of variation of the distribution and the correlation between the floors’ masses. The procedure allows to obtain optimal designs of the control system that are robust with respect to the uncertainties on the distribution of the dead and live loads.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001826578
|
oai_dc
|
Semi-active structural fuzzy control with MR dampers subjected to near-fault ground motions having forward directivity and fling step
|
Semi-active structural fuzzy control with MR dampers subjected to near-fault ground motions having forward directivity and fling step
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hosein Ghaffarzadeh(University of Tabriz)"
] |
Semi-active control equipments are used to effectually enhance the seismic behavior of structures. Magneto-rheological (MR) dampers are semi-active devices that can be utilized to control the response of structures during seismic loads and have received voracious attention for response suppression. They supply the adaptability of active devices and stability and reliability of passive devices. This paper presents an optimal fuzzy logic control scheme for vibration mitigation of buildings using magneto-rheological dampers subjected to near-fault ground motions. Near-fault features including a directivity pulse in the fault-normal direction and a fling step in the fault-parallel direction are considered in the requisite ground motion records. The membership functions and fuzzy rules of fuzzy controller were optimized by genetic algorithm (GA). Numerical study is performed to analyze the influences of near-fault ground motions on a building that is equipped with MR dampers. Considering the uncontrolled system response as the base line, the proposed method is scrutinized by analogy with that of a conventional maximum dissipation energy (MED) controller to accentuate the effectiveness of the fuzzy logic algorithm. Results reveal that the fuzzy logic controllers can efficiently improve the structural responses and MR dampers are quite promising for reducing seismic responses during near-fault earthquakes.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001742398
|
oai_dc
|
Complete decentralized displacement control algorithm
|
Complete decentralized displacement control algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M.E. Ruiz-Sandoval(Universidad Autonoma Metropolitana); E. Morales(Universidad Autonoma Metropolitana)"
] |
Control systems have been greatly studied in recent years and can be classified as: passive, active, semi-active or hybrid systems. Most forms of control systems have been applied in a centralized manner where all the information is sent to a central node where control the algorithm is then calculated. One of the possible problems of centralized control is the difficulty to scale its application. In this paper, a completely decentralized control algorithm is analytically implemented. The algorithm considers that each of the control systems makes the best decision based solely on the information collected at its location. Semi-active control is used in preference to active control because it has minimal energy consumption, little to no possibility of destabilization, a reduction in the possibility of data saturation, and a reduction in the response time in comparison to centralized control.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001742401
|
oai_dc
|
Damage detection in beam-type structures via PZT’s dual piezoelectric responses
|
Damage detection in beam-type structures via PZT’s dual piezoelectric responses
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Khac-Duy Nguyen(부경대학교); 김정태(부경대학교); Duc-Duy Ho(Ho Chi Minh City University of Technology)"
] |
In this paper, practical methods to utilize PZT’s dual piezoelectric effects (i.e., dynamic strain and electro-mechanical (E/M) impedance responses) for damage detection in beam-type structures are presented. In order to achieve the objective, the following approaches are implemented. Firstly, PZT material’s dual piezoelectric characteristics on dynamic strain and E/M impedance are investigated. Secondly, global vibration-based and local impedance-based methods to detect the occurrence and the location of damage are presented. Finally, the vibration-based and impedance-based damage detection methods using the dual piezoelectric responses are evaluated from experiments on a lab-scaled beam for several damage scenarios. Damage detection results from using PZT sensor are compared with those obtained from using accelerometer and electric strain gauge.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001742397
|
oai_dc
|
Modular and versatile platform for the benchmarking of modern actuators for robots
|
Modular and versatile platform for the benchmarking of modern actuators for robots
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Elena Garcia(Centre for Automation and Robotics -CSIC-UPM); Pablo Gonzalez-de-Santos(Centre for Automation and Robotics -CSIC-UPM)"
] |
This work presents a test platform for the assessment and benchmarking of modern actuators which have been specifically developed for the new field and service robotics applications. This versatile platform has been designed for the comparative analysis of actuators of dissimilar technology and operating conditions. It combines a modular design to adapt to linear and rotational actuators of different sizes, shapes and functions, as well as those with different load capacities, power and displacement. This test platform emulates the kinematics of robotic joints while an adaptive antagonist-load actuator allows reproducing the variable dynamic loads that actuators used in real robotics applications will be subjected to. A data acquisition system is used for monitoring and analyzing test actuator performance. The test platform combines hardware and software in the loop to allow actuator performance characterization. The use of the proposed test platform is demonstrated through the characterization and benchmarking of three controllable impedance actuators recently being incorporated into modern robotics.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001742399
|
oai_dc
|
Simultaneous active strain and ultrasonic measurement using fiber acoustic wave piezoelectric transducers
|
Simultaneous active strain and ultrasonic measurement using fiber acoustic wave piezoelectric transducers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J.R. Lee(전북대학교); C.W. Kong(항공우주연구원); C.Y. Park(국방과학연구소)"
] |
We developed a simultaneous strain measurement and damage detection technique using a pair of surface-mounted piezoelectric transducers and a fiber connecting them. This is a novel sensor configuration of the fiber acoustic wave (FAW) piezoelectric transducer. In this study, lead-zirconate-titanate (PZT) transducers are installed conventionally on a plate’s surface, which is a technique used in many structural health monitoring studies. However, our PZTs are also connected with an optical fiber. A FAW and Lamb wave are simultaneously guided in the optical fiber and the structure, respectively. The dependency of the time-of-flight of the FAW on the applied strain is quantified for strain sensing. In our experimental results, the FAW exhibited excellent linear behavior and no hysteresis with respect to the change in strain. On the other hand, the well-known damage detection function of the surface-mounted PZT transducers was still available by monitoring the waveform change in the conventional Lamb wave ultrasonic path.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001742400
|
oai_dc
|
Vibration measurement and vulnerability analysis of a power plant cooling system
|
Vibration measurement and vulnerability analysis of a power plant cooling system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Özgür ANIL(Gazi University); Sami Oğuzhan AKBAŞ(Gazi University); Erkan KANTAR(Celalbayar University); A. Cem GEL(Gazi University)"
] |
During the service life of a structure, design complications and unexpected events may induce unforeseen vibrations. These vibrations can be generated by malfunctioning machinery or machines that are modified or placed without considering the original structural design because of a change in the intended use of the structure. Significant vibrations occurred at a natural gas plant cooling structure during its operation due to cavitation effect within the hydraulic system. This study presents findings obtained from the in-situ vibration measurements and following finite-element analyses of the cooling structure. Comments are made on the updated performance level and damage state of the structure using the results of these measurements and corresponding numerical analyses. An attempt was also made to assess the applicability of traditional displacement-based vulnerability estimation methods in the health monitoring of structures under vibrations with a character different from those due to seismic excitations.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001770000
|
oai_dc
|
Remote structural health monitoring systems for next generation SCADA
|
Remote structural health monitoring systems for next generation SCADA
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김세환(University of California); Pai H. Chou(University of California); Marco Torbol(Univ. of California)"
] |
Recent advances in low-cost remote monitoring systems have made it possible and practical to perform structural health monitoring (SHM) on a large scale. However, it is difficult for a single remote monitoring system to cover a wide range of SHM applications due to the amount of specialization required. For the remote monitoring system to be flexible, sustainable, and robust, this article introduces a new cost-effective, advanced remote monitoring and inspection system named DuraMote that can serve as a next generation supervisory control and data acquisition (SCADA) system for civil infrastructure systems. To evaluate the performance of DuraMote, we conduct experiments at two representative counterpart sites: a bridge and water pipelines. The objectives of this article are to improve upon the existing SCADA by integrating the remote monitoring system (i.e., DuraMote), to describe a prototype SCADA for civil engineering structures, and to validate its effectiveness with long-term field deployment results.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001770001
|
oai_dc
|
System identification of a cable-stayed bridge using vibration responses measured by a wireless sensor network
|
System identification of a cable-stayed bridge using vibration responses measured by a wireless sensor network
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김정태(부경대학교); Duc-Duy Ho(Ho Chi Minh City University of Technology); Khac-Duy Nguyen(Pukyong National University); 홍동수(부경대학교); 신성우(부경대학교); 윤정방(울산과학기술대학교); Masanobu Shinozuka(Univ. of California)"
] |
In this paper, system identification of a cable-stayed bridge in Korea, the Hwamyung Bridge, is performed using vibration responses measured by a wireless sensor system. First, an acceleration based-wireless sensor system is employed for the structural health monitoring of the bridge, and wireless sensor nodes are deployed on a deck, a pylon and several selected cables. Second, modal parameters of the bridge are obtained both from measured vibration responses and finite element (FE) analysis. Frequency domain decomposition and stochastic subspace identification methods are used to obtain the modal parameters from the measured vibration responses. The FE model of the bridge is established using commercial FE software package. Third, structural properties of the bridge are updated using a modal sensitivity-based method. The updating work improves the accuracy of the FE model so that structural behaviors of the bridge can be represented better using the updated FE model. Finally, cable forces of the selected cables are also identified and compared with both design and lift-off test values.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001769998
|
oai_dc
|
Develoment of high-sensitivity wireless strain sensor for structural health monitoring
|
Develoment of high-sensitivity wireless strain sensor for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"조홍기(UIUC); B.F. Spencer, Jr.(UIUC); 박종웅(한국과학기술원); 정형조(한국과학기술원)"
] |
Due to their cost-effectiveness and ease of installation, wireless smart sensors (WSS) have received considerable recent attention for structural health monitoring of civil infrastructure. Though various wireless smart sensor networks (WSSN) have been successfully implemented for full-scale structural health monitoring (SHM) applications, monitoring of low-level ambient strain still remains a challenging problem for WSS due to A/D converter (ADC) resolution, inherent circuit noise, and the need for automatic operation. In this paper, the design and validation of high-precision strain sensor board for the Imote2 WSS platform and its application to SHM of a cable-stayed bridge are presented. By accurate and automated balancing of the Wheatstone bridge, signal amplification of up to 2507-times can be obtained, while keeping signal mean close to the center of the ADC span, which allows utilization of the full span of the ADC. For better applicability to SHM for real-world structures, temperature compensation and shunt calibration are also implemented. Moreover, the sensor board has been designed to accommodate a friction-type magnet strain sensor, in addition to traditional foil-type strain gages, facilitating fast and easy deployment. The wireless strain sensor board performance is verified through both laboratory-scale tests and deployment on a full-scale cable-stayed bridge.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001770002
|
oai_dc
|
Energy harvesting techniques for remote corrosion monitoring systems
|
Energy harvesting techniques for remote corrosion monitoring systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김세환(University of California); 나웅진(국토해양부)"
] |
An Remote Corrosion Monitoring (RCM) system consists of an anode with low potential, the metallic structures against corrosion, an electrode to provide reference potential, and a data-acquisition system to ensure the potential difference for anticorrosion. In more detail, the data-acquisition (DAQ) system monitors the potential difference between the metallic structures and a reference electrode to identify the correct potential level against the corrosion of the infrastructures. Then, the measured data are transmitted to a central office to remotely keep track of the status of the corrosion monitoring (CM) system. To date, the RCM system is designed to achieve low power consumption, so that it can be simply powered by batteries. However, due to memory effect and the limited number of recharge cycles, it can entail the maintenance fee or sometimes cause failure to protect the metallic structures. To address this issue, the low-overhead energy harvesting circuitry for the RCM systems has designed to replenish energy storage elements (ESEs) along with redeeming the leakage of supercapacitors. Our developed energy harvester can scavenge the ambient energy from the corrosion monitoring environments and store it as useful electrical energy for powering local data-acquisition systems. In particular, this paper considers the energy harvesting from potential difference due to galvanic corrosion between a metallic infrastructure and a permanent copper/copper sulfate reference electrode. In addition, supercapacitors are adopted as an ESE to compensate for or overcome the limitations of batteries. Experimental results show that our proposed harvesting schemes significantly reduce the overhead of the charging circuitry, which enable fully charging up to a 350-F supercapacitor under the low corrosion power of 3 mW (i.e., 1 V/3 mA).
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001769999
|
oai_dc
|
A scheme on multi-tier heterogeneous networks for citywide damage monitoring in an earthquake
|
A scheme on multi-tier heterogeneous networks for citywide damage monitoring in an earthquake
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Takahiro Fujiwara(Hakodate National College of Technology); Takashi Watanabe(Shizuoka University); Masanobu Shinozuka(University of California Irvine)"
] |
Quick, accurate damage monitoring is strongly required for damage assessment in the aftermath of a large natural disaster. Wireless sensor networks are promising technologies to acquire damage information in a citywide area. The wireless sensor networks, however, would be faced with difficulty to collect data in real-time and to expand the scalability of the networks. This paper discusses a scheme of network architecture to cove a whole city in multi-tier heterogeneous networks, which consist of wireless sensor networks, access networks and a backbone network. We first review previous studies for citywide damage monitoring, and then discuss the feature of multi-tier heterogeneous networks to cover a citywide area.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001769997
|
oai_dc
|
Long term monitoring of a cable stayed bridge using DuraMote
|
Long term monitoring of a cable stayed bridge using DuraMote
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marco Torbol(University of California); 김세환(University of California); Masanobu Shinozuka(University of California)"
] |
DuraMote is a remote sensing system developed for the “NIST TIP project: next generation SCADA for prevention and mitigation of water system infrastructure disaster”. It is designed for supervisory control and data acquisition (SCADA) of ruptures in water pipes. Micro-electro mechanical (MEMS) accelerometers, which record the vibration of the pipe wall, are used detect the ruptures. However, the performance of Duramote cannot be verified directly on a water distribution system because it lacks an acceptable recordable level of ambient vibration. Instead, a long-span cable-stayed bridge is an ideal test-bed to validate the accuracy, the reliability, and the robustness of DuraMote because the bridge has an acceptable level of ambient vibration. The acceleration data recorded on the bridge were used to identify the modal properties of the structure and to verify the performance of DuraMote. During the test period, the bridge was subjected to heavy rain, wind, and a typhoon but the system demonstrates its robustness and durability.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001769996
|
oai_dc
|
Semi-active damped outriggers for seismic protection of high-rise buildings
|
Semi-active damped outriggers for seismic protection of high-rise buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chia-Ming Chang(University of Illinois at Urbana-Champaign); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Zhihao Wang(North China Inst, Water Conservancy and Hydroelect); Zhengqing Chen(Hunan University)"
] |
High-rise buildings are a common feature of urban cities around the world. These flexible structures frequently exhibit large vibration due to strong winds and earthquakes. Structural control has been employed as an effective means to mitigate excessive responses; however, structural control mechanisms that can be used in tall buildings are limited primarily to mass and liquid dampers. An attractive alternative can be found in outrigger damping systems, where the bending deformation of the building is transformed into shear deformation across dampers placed between the outrigger and the perimeter columns. The outrigger system provides additional damping that can reduce structural responses, such as the floor displacements and accelerations. This paper investigates the potential of using smart dampers, specifically magnetorheological (MR) fluid dampers, in the outrigger system. First, a high-rise building is modeled to portray the St. Francis Shangri-La Place in Philippines. The optimal performance of the outrigger damping system for mitigation of seismic responses in terms of damper size and location also is subsequently evaluated. The efficacy of the semi-active damped outrigger system is finally verified through numerical simulation.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793216
|
oai_dc
|
A statistical reference-free damage identification for real-time monitoring of truss bridges using wavelet-based log likelihood ratios
|
A statistical reference-free damage identification for real-time monitoring of truss bridges using wavelet-based log likelihood ratios
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이순기(대우조선해양); 윤군진(University of Akron)"
] |
In this paper, a statistical reference-free real-time damage detection methodology is proposed for detecting joint and member damage of truss bridge structures. For the statistical damage sensitive index (DSI), wavelet packet decomposition (WPD) in conjunction with the log likelihood ratio was suggested. A sensitivity test for selecting a wavelet packet that is most sensitive to damage level was conducted and determination of the level of decomposition was also described. Advantages of the proposed method for applications to real-time health monitoring systems were demonstrated by using the log likelihood ratios instead of likelihood ratios. A laboratory truss bridge structure instrumented with accelerometers and a shaker was used for experimental verification tests of the proposed methodology. The statistical reference-free real-time damage detection algorithm was successfully implemented and verified by detecting three damage types frequently observed in truss bridge structures – such as loss of bolts, loosening of bolts at multiple locations, sectional loss of members – without reference signals from pristine structure. The DSI based on WPD and the log likelihood ratio showed consistent and reliable results under different damage scenarios.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793217
|
oai_dc
|
An integrated monitoring system for life-cycle management of wind turbines
|
An integrated monitoring system for life-cycle management of wind turbines
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kay Smarsly(Stanford University); Dietrich Hartmann(Ruhr-University Bochum); Kincho H. Law(Stanford University)"
] |
With an annual growth rate of about 30%, wind energy systems, such as wind turbines, represent one of the fastest growing renewable energy technologies. Continuous structural health monitoring of wind turbines can help improving structural reliability and facilitating optimal decisions with respect to maintenance and operation at minimum associated life-cycle costs. This paper presents an integrated monitoring system that is designed to support structural assessment and life-cycle management of wind turbines. The monitoring system systematically integrates a wide variety of hardware and software modules, including sensors and computer systems for automated data acquisition, data analysis and data archival, a multiagent-based system for self-diagnosis of sensor malfunctions, a model updating and damage detection framework for structural assessment, and a management module for monitoring the structural condition and the operational efficiency of the wind turbine. The monitoring system has been installed on a 500 kW wind turbine located in Germany. Since its initial deployment in 2009, the system automatically collects and processes structural, environmental, and operational wind turbine data. The results demonstrate the potential of the proposed approach not only to ensure continuous safety of the structures, but also to enable cost-efficient maintenance and operation of wind turbines.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793212
|
oai_dc
|
Predictive model of fatigue crack detection in thick bridge steel structures with piezoelectric wafer active sensors
|
Predictive model of fatigue crack detection in thick bridge steel structures with piezoelectric wafer active sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Gresil(University of South Carolina); L. Yu(University of South Carolina); Y. Shen(University of South Carolina); V. Giurgiutiu(University of South Carolina)"
] |
This paper presents numerical and experimental results on the use of guided waves for structural health monitoring (SHM) of crack growth during a fatigue test in a thick steel plate used for civil engineering application. Numerical simulation, analytical modeling, and experimental tests are used to prove that piezoelectric wafer active sensor (PWAS) can perform active SHM using guided wave pitch-catch method and passive SHM using acoustic emission (AE). AE simulation was performed with the multi-physic FEM (MP-FEM) approach. The MP-FEM approach permits that the output variables to be expressed directly in electric terms while the two-ways electromechanical conversion is done internally in the MP-FEM formulation. The AE event was simulated as a pulse of defined duration and amplitude. The electrical signal measured at a PWAS receiver was simulated. Experimental tests were performed with PWAS transducers acting as passive receivers of AE signals. An AE source was simulated using 0.5-mm pencil lead breaks. The PWAS transducers were able to pick up AE signal with good strength. Subsequently, PWAS transducers and traditional AE transducer were applied to a 12.7-mm CT specimen subjected to accelerated fatigue testing. Active sensing in pitch catch mode on the CT specimen was applied between the PWAS transducers pairs. Damage indexes were calculated and correlated with actual crack growth. The paper finishes with conclusions and suggestions for further work.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793214
|
oai_dc
|
Optimum tuned mass damper design for preventing brittle fracture of RC buildings
|
Optimum tuned mass damper design for preventing brittle fracture of RC buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sinan Melih Nigdeli(Istanbul University); Gebrail Bekdas(Istanbul University)"
] |
Brittle fracture of structures excited by earthquakes can be prevented by adding a tuned mass damper (TMD). This TMD must be optimum and suitable to the physical conditions of the structure. Compressive strength of concrete is an important factor for brittle fracture. The application of a TMD to structures with low compressive strength of concrete may not be possible if the weight of the TMD is too much. A heavy TMD is dangerous for these structures because of insufficient axial force capacity of structure. For the preventing brittle fracture, the damping ratio of the TMD must be sufficient to reduce maximum shear forces below the values proposed in design regulations. Using the formulas for frequency and damping ratio related to a preselected mass, this objective can be only achieved by increasing the mass of the TMD. By using a metaheuristic method, the optimum parameters can be searched in a specific limit. In this study, Harmony Search (HS) is employed to find optimum TMD parameters for preventing brittle fracture by reducing shear force in additional to other time and frequency responses. The proposed method is feasible for the retrofit of weak structures with insufficient compressive strength of concrete.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793215
|
oai_dc
|
Seismic response control of buildings with force saturation constraints
|
Seismic response control of buildings with force saturation constraints
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Filippo Ubertini(University of Perugia); A. Luigi Materazzi(University of Perugia)"
] |
We present an approach, based on the state dependent Riccati equation, for designing non-collocated seismic response control strategies for buildings accounting for physical constraints, with particular attention to force saturation. We consider both cases of active control using general actuators and semi-active control using magnetorheological dampers. The formulation includes multi control devices, acceleration feedback and time delay compensation. In the active case, the proposed approach is a generalization of the classic linear quadratic regulator, while, in the semi-active case, it represents a novel generalization of the well-established modified clipped optimal approach. As discussed in the paper, the main advantage of the proposed approach with respect to existing strategies is that it allows to naturally handle a broad class of non-linearities as well as different types of control constraints, not limited to force saturation but also including, for instance, displacement limitations. Numerical results on a typical building benchmark problem demonstrate that these additional features are achieved with essentially the same control effectiveness of existing saturation control strategies.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001793213
|
oai_dc
|
Beam structural system moving forces active vibration control using a combined innovative control approach
|
Beam structural system moving forces active vibration control using a combined innovative control approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ming-Hui Lee(Chinese Military Academy)"
] |
This study proposes an innovative control approach to suppress the responses of a beam structural system under moving forces. The proposed control algorithm is a synthesis of the adaptive input estimation method (AIEM) and linear quadratic Gaussian (LQG) controller. Using the synthesis algorithm the moving forces can be estimated using AIEM while the LQG controller offers proper control forces to effectively suppress the beam structural system responses. Active control numerical simulations of the beam structural system are performed to evaluate the feasibility and effectiveness of the proposed control technique. The numerical simulation results show that the proposed method has more robust active control performance than the conventional LQG method.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001667193
|
oai_dc
|
Analysis and simulation of multi-mode piezoelectric energy harvesters
|
Analysis and simulation of multi-mode piezoelectric energy harvesters
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ying Zhang(Georgia Institute of Technology); Binghu Zhu(Georgia Institute of Technology)"
] |
Theoretical analysis is performed on a multi-mode energy harvester design with focus on the first two vibration modes. Based on the analysis, a modification is proposed for designing a novel adaptive multimode energy harvester. The device comprises a simply supported beam with distributed mass and piezoelectric elements, and an adaptive damper that provides a 180 degree phase shift for the motions of two supports only at the second vibration mode. Theoretical analysis and numerical simulations show that the new design can efficiently scavenge energy at the first two vibration modes. The energy harvesting capability of the multimode energy harvester is also compared with that of a cantilever-based energy harvester for single-mode vibration. The results show that the energy harvesting capacity is affected by the damping ratios of different designs. For fixed damping ratio and design dimensions, the multi-mode design has higher energy harvesting capacity than the cantilever-based design.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000090.xml
|
||
ART001667187
|
oai_dc
|
Smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection
|
Smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Khac-Duy Nguyen(Pukyong National University); 김정태(부경대학교)"
] |
For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly,wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZTinterface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000090.xml
|
||
ART001667192
|
oai_dc
|
Flexible tactile sensor array for foot pressure mapping system in a biped robot
|
Flexible tactile sensor array for foot pressure mapping system in a biped robot
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cheng-Hsin Chuang(Southern Taiwan University); Yi-Rong Liou(Southern Taiwan University); Ming-Yuan Shieh(Southern Taiwan University)"
] |
Controlling the balance of motion in a context involving a biped robot navigating a rugged surface or a step is a difficult task. In the present study, a 3×5 flexible piezoelectric tactile sensor array is developed to provide a foot pressure map and zero moment point for a biped robot. We introduce an innovative concept involving structural electrodes on a piezoelectric film in order to improve the sensitivity. The tactile sensor consists of a polymer piezoelectric film, PVDF, between two patterned flexible print circuit substrates (FPC). Additionally, a silicon rubber bump-like structure is attached to the FPC and covered by a polydimethylsiloxane (PDMS) layer. Experimental results show that the output signal of the sensor exhibits a linear behavior within 0.2 N ~ 9 N, while its sensitivity is approximately 42 mV/N. According to the characteristic of the tactile sensor, the readout module is designed for an in-situ display of the pressure magnitudes and distribution within 3×5 taxels. Furthermore, the trajectory of the zero moment point (ZMP) can also be calculated by this program. Consequently, our tactile sensor module can provide the pressure map and ZMP information to the in-situ feedback to control the balance of moment for a biped robot.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000090.xml
|
||
ART001667190
|
oai_dc
|
Stochastic hygrothermoelectromechanical loaded post buckling analysis of piezoelectric laminated cylindrical shell panel
|
Stochastic hygrothermoelectromechanical loaded post buckling analysis of piezoelectric laminated cylindrical shell panel
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Achchhe Lal(S.V. National Institute of Technology); Nitesh Saidane(Indian Institute of Technology); B.N. Singh(Indian Institute of Technology)"
] |
The present work deals with second order statistics of post buckling response of piezoelectric laminated composite cylindrical shell panel subjected to hygro-thermo-electro-mechanical loading with random system properties. System parameters such as the material properties, thermal expansion coefficients and lamina plate thickness are assumed to be independent of the temperature and electric field and modeled as random variables. The piezoelectric material is used in the forms of layers surface bonded on the layers of laminated composite shell panel. The mathematical formulation is based on higher order shear deformation shell theory (HSDT) with von-Karman nonlinear kinematics. A efficient C0 nonlinear finite element method based on direct iterative procedure in conjunction with a first order perturbation approach (FOPT) is developed for the implementation of the proposed problems in random environment and is employed to evaluate the second order statistics (mean and variance) of the post buckling load of piezoelectric laminated cylindrical shell panel. Typical numerical results are presented to examine the effect of various environmental conditions, amplitude ratios, electrical voltages, panel side to thickness ratios, aspect ratios, boundary conditions, curvature to side ratios, lamination schemes and types of loadings with random system properties. It is observed that the piezoelectric effect has a significant influence on the stochastic post buckling response of composite shell panel under various loading conditions and some new results are presented to demonstrate the applications of present work. The results obtained using the present solution approach is validated with those results available in the literature and also with independent Monte Carlo Simulation (MCS).
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000090.xml
|
||
ART001667186
|
oai_dc
|
Bridge safety monitoring based-GPS technique: case study Zhujiang Huangpu Bridge
|
Bridge safety monitoring based-GPS technique: case study Zhujiang Huangpu Bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mosbeh R. Kaloop(Mansoura University)"
] |
GPS has become an established technique in structural health monitoring. This paper presents the application of an on-line GPS RTK system on the Zhujiang Huangpu Bridge (China) for monitoring bridge deck and towers movements. In this study, both the form and functions of movements of the deck and towers of the bridge under affecting loads were monitored in lateral, longitudinal and vertical directions. Such movements were described in time and frequency domains by determining the trend, torsion, periodical of the series using probability density function (PDF). The results of the time series GPS data are practical and useful to bridge health monitoring.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000090.xml
|
||
ART001812594
|
oai_dc
|
Field application of elasto-magnetic stress sensors for monitoring of cable tension force in cable-stayed bridges
|
Field application of elasto-magnetic stress sensors for monitoring of cable tension force in cable-stayed bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"임진석((주)삼성물산 건설부문); 신성우(부경대학교); Ming L. Wang(Northeastern University); 윤정방(울산과학기술대학교); 정형조(한국과학기술원); 김정태(부경대학교); 음승현(한국과학기술원)"
] |
Recently, a novel stress sensor, which utilizes the elasto-magnetic (EM) effect of ferromagnetic materials, has been developed to measure stress in steel cables and wires. In this study, the effectiveness of this EM based stress sensors for monitoring of the cable tension force of a real scale cable-stayed bridge was investigated. Two EM stress sensors were installed on two selected multi-strand cables in Hwa-Myung Bridge, Busan, South Korea. Conventional lift-off test was conducted to obtain reference cable tension forces of two test cables. The reference forces were used to calibrate and validate cable tension force measurements from the EM sensors. Tension force variations of two test cables during the second tensioning work on Hwa-Myung Bridge were monitored using the EM sensors. Numerical simulations were conducted to compare and verify the monitoring results. Based on the results, the effectiveness of EM sensors for accurate field monitoring of the cable tension force of cable-stayed bridge is discussed.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812577
|
oai_dc
|
Wireless sensor network for decentralized damage detection of building structures
|
Wireless sensor network for decentralized damage detection of building structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박종웅(한국과학기술원); 심성한(울산과학기술대학교); 정형조(한국과학기술원)"
] |
The smart sensor technology has opened new horizons for assessing and monitoring structural health of civil infrastructure. Smart sensor’s unique features such as onboard computation, wireless communication, and cost effectiveness can enable a dense network of sensors that is essential for accurate assessment of structural health in large-scale civil structures. While most research efforts to date have been focused on realizing wireless smart sensor networks (WSSN) on bridge structures, relatively less attention is paid to applying this technology to buildings. This paper presents a decentralized damage detection using the WSSN for building structures. An existing flexibility-based damage detection method is extended to be used in the decentralized computing environment offered by the WSSN and implemented on MEMSIC’s Imote2 smart sensor platform. Numerical simulation and laboratory experiment are conducted to validate the WSSN for decentralized damage detection of building structures.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812579
|
oai_dc
|
Enhanced damage index method using torsion modes of structures
|
Enhanced damage index method using torsion modes of structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"임석빈(삼성물산); Stefan Hurlebaus(Texas A&M University); Harding C. Cloudt(Texas A&M University); Jeffrey A. Fogle(Texas A&M University)"
] |
A growing need has developed in the United States to obtain more specific knowledge on the structural integrity of infrastructure due to aging service lives, heavier and more frequent loading conditions, and durability issues. This need has spurred extensive research in the area of structural health monitoring over the past few decades. Several structural health monitoring techniques have been developed that are capable of locating damage in structures using modal strain energy of mode shapes. Typically in the past, bending strain energy has been used in these methods since it is a dominant vibrational mode in many structures and is easily measured. Additionally, there may be cases, such as pipes, shafts, or certain bridges, where structures exhibit significant torsional behavior as well. In this research, torsional strain energy is used to locate damage. The damage index method is used on two numerical models; a cantilevered steel pipe and a simply-supported steel plate girder bridge. Torsion damage indices are compared to bending damage indices to assess their effectiveness at locating damage. The torsion strain energy method is capable of accurately locating damage and providing additional valuable information to both of the structures’ behaviors.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812580
|
oai_dc
|
Simplified planar model for damage estimation of interlocked caisson system
|
Simplified planar model for damage estimation of interlocked caisson system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Thanh-Canh Huynh(부경대학교); 김정태(부경대학교); 이소영(부경대학교); 박우선(한국해양과학기술원); 한상훈(한국해양과학기술원)"
] |
In this paper, a simplified planar model is developed for damage estimation of interlocked caisson systems. Firstly, a conceptual dynamic model of the interlocked caisson system is designed on the basis of the characteristics of existing harbor caisson structures. A mass-spring-dashpot model allowing only the sway motion is formulated. To represent the condition of interlocking mechanisms, each caisson unit is connected to adjacent ones via springs and dashpots. Secondly, the accuracy of the planar model‟s vibration analysis is numerically evaluated on a 3-D FE model of the interlocked caisson system. Finally, the simplified planar model is employed for damage estimation in the interlocked caisson system. For localizing damaged caissons, a damage detection method based on modal strain energy is formulated for the caisson system.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812578
|
oai_dc
|
Rapid full-scale expansion joint monitoring using wireless hybrid sensor
|
Rapid full-scale expansion joint monitoring using wireless hybrid sensor
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"장신애(University of Connecticut); Sushil Dahal(University of Connecticut); Jingcheng Li(University of Connecticut)"
] |
Condition assessment and monitoring of bridges is critical for safe passenger travel, public transportation, and efficient freight. In monitoring, displacement measurement capability is important to keep track of performance of bridge, in part or as whole. One of the most important parts of a bridge is the expansion joint, which accommodates continuous cyclic thermal expansion of the whole bridge. Though expansion joint is critical for bridge performance, its inspection and monitoring has not been considered significantly because the monitoring requires long-term data using cost intensive equipment. Recently, a wireless smart sensor network (WSSN) has drawn significant attention for transportation infrastructure monitoring because of its merits in low cost, easy installation, and versatile on-board computation capability. In this paper, a rapid wireless displacement monitoring system, wireless hybrid sensor (WHS), has been developed to monitor displacement of expansion joints of bridges. The WHS has been calibrated for both static and dynamic displacement measurement in laboratory environment, and deployed on an in-service highway bridge to demonstrate rapid expansion joint monitoring. The test-bed is a continuous steel girder bridge, the Founders Bridge, in East Hartford, Connecticut. Using the WHS system, the static and dynamic displacement of the expansion joint has been measured. The short-term displacement trend in terms of temperature is calculated. With the WHS system, approximately 6% of the time has been spent for installation, and 94% of time for the measurement showing strong potential of the developed system for rapid displacement monitoring.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812576
|
oai_dc
|
Wireless health monitoring of stay cable using piezoelectric strain response and smart skin technique
|
Wireless health monitoring of stay cable using piezoelectric strain response and smart skin technique
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김정태(부경대학교); Khac-Duy Nguyen(부경대학교); Thanh-Canh Huynh(부경대학교)"
] |
In this paper, wireless health monitoring of stay cables using piezoelectric strain sensors and a smart skin technique is presented. For the cables, tension forces are estimated to examine their health status from vibration features with consideration of temperature effects. The following approaches are implemented to achieve the objective. Firstly, the tension force estimation utilizing the piezoelectric sensor-embedded smart skin is presented. A temperature correlation model to recalculate the tension force at a temperature of interest is designed by correlating the change in cable’s dynamic features and temperature variation. Secondly, the wireless health monitoring system for stay cables is described. A piezoelectric strain sensor node and a tension force monitoring software which is embedded in the sensor are designed. Finally, the feasibility of the proposed monitoring technique is evaluated on stay cables of the Hwamyung Grand Bridge in Busan, Korea.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001812575
|
oai_dc
|
A vision-based system for dynamic displacement measurement of long-span bridges: algorithm and verification
|
A vision-based system for dynamic displacement measurement of long-span bridges: algorithm and verification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.W. Ye(The Hong Kong Polytechnic University); Y. Q. Ni(The Hong Kong Polytechnic University); T.T. Wai(The Hong Kong Polytechnic University); K.Y. Wong(The Hong Kong SAR Government); X.M. Zhang(e Hong Kong Polytechnic University Shenzhen Research Institute); F. Xu(The Hong Kong Polytechnic University)"
] |
Dynamic displacement of structures is an important index for in-service structural condition and behavior assessment, but accurate measurement of structural displacement for large-scale civil structures such as long-span bridges still remains as a challenging task. In this paper, a vision-based dynamic displacement measurement system with the use of digital image processing technology is developed, which is featured by its distinctive characteristics in non-contact, long-distance, and high-precision structural displacement measurement. The hardware of this system is mainly composed of a high-resolution industrial CCD (charge-coupled-device) digital camera and an extended-range zoom lens. Through continuously tracing and identifying a target on the structure, the structural displacement is derived through cross-correlation analysis between the predefined pattern and the captured digital images with the aid of a pattern matching algorithm. To validate the developed system, MTS tests of sinusoidal motions under different vibration frequencies and amplitudes and shaking table tests with different excitations (the El-Centro earthquake wave and a sinusoidal motion) are carried out. Additionally, in-situ verification experiments are performed to measure the mid-span vertical displacement of the suspension Tsing Ma Bridge in the operational condition and the cable-stayed Stonecutters Bridge during loading tests. The obtained results show that the developed system exhibits an excellent capability in real-time measurement of structural displacement and can serve as a good complement to the traditional sensors.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001819359
|
oai_dc
|
Robust inverse identification of piezoelectric and dielectric effective behaviors of a bonded patch to a composite plate
|
Robust inverse identification of piezoelectric and dielectric effective behaviors of a bonded patch to a composite plate
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ayech Benjeddou(Institut Supérieur de Mécanique de Paris); Mohsen Hamdi(Inst. Préparatoire aux Etudes d’Ingénieurs de Nabe); Samir Ghanmi(Inst. Préparatoire aux Etudes d’Ingénieurs de Nabe)"
] |
Piezoelectric and dielectric behaviors of a piezoceramic patch adhesively centered on a carbon composite plate are identified using a robust multi–objective optimization procedure. For this purpose, the patch piezoelectric stress coupling and blocked dielectric constants are automatically evaluated for a wide frequency range and for the different identifiable behaviors. Latters’ symmetry conditions are coded in the design plans serving for response surface methodology–based sensitivity analysis and meta-modeling. The identified constants result from the measured and computed open-circuit frequencies deviations minimization by a genetic algorithm that uses meta-model estimated frequencies. Present investigations show that the bonded piezoceramic patch has effective three-dimensional (3D) orthotropic piezoelectric and dielectric behaviors. Besides, the sensitivity analysis indicates that four constants, from eight, dominate the 3D orthotropic behavior, and that the analyses can be reduced to the electromechanically coupled modes only; therefore, in this case, and if only the dominated parameters are optimized while the others keep their nominal values, the resulting piezoelectric and dielectric behaviors are found to be transverse–isotropic. These results can help designing piezoceramics smart composites for various applications like noise,vibration, shape, and health control.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001819365
|
oai_dc
|
Enthalpy – based homogenization procedure for composite piezoelectric modules with integrated electrodes
|
Enthalpy – based homogenization procedure for composite piezoelectric modules with integrated electrodes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Burkhard Kranz(Fraunhofer Inst. for Machine Tools and Forming Technology); Ayech Benjeddou(Institut Supérieur de Mécanique de Paris); Welf-Guntram Drossel(Chemnitz University of Technology)"
] |
A new enthalpy – based procedure for the homogenization of the electromechanical material parameters of composite piezoelectric modules with integrated electrodes is presented. It is based on a finite element (FE) modeling of the latter’s representative volume element (RVE). In contrast to most previously published homogenization approaches that are based on averaged quantities, the presented method uses a direct evaluation of the electromechanical enthalpy. Hence, for the linear orthotropic piezoelectric composite behavior full set of elastic, piezoelectric, and dielectric material parameters, 17 load cases (LC) are used where each load case leads directly to one material parameter. This gives the possibility to elaborate a very strict and easy to program processing. In conjunction with the 17 LC, the enthalpy – based homogenization is particularly suitable for laminated composite piezoelectric modules with integrated electrodes. In this case, the electric load has to be given at the electrodes rather than at the RVE FE model boundaries. The proposed procedure is validated through its comparison to literature available results on a classical 1-3 piezoelectric micro fiber (longitudinally polarized) reinforced composite and a shear piezoelectric macro-fiber (transversely polarized) composite module.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001819358
|
oai_dc
|
Active shape control of a cantilever by resistively interconnected piezoelectric patches
|
Active shape control of a cantilever by resistively interconnected piezoelectric patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Schoeftner(Johannes Kepler University Linz); G. Buchberger(Johannes Kepler University Linz)"
] |
This paper is concerned with static and dynamic shape control of a laminated Bernoulli-Euler beam hosting a uniformly distributed array of resistively interconnected piezoelectric patches. We present an analytical one-dimensional model for a laminated piezoelectric beam with material discontinuities within the framework of Bernoulli-Euler and extent the model by a network of resistors which are connected to several piezoelectric patch actuators. The voltage of only one piezoelectric patch is prescribed: we answer the question how to design the interconnected resistive electric network in order to annihilate lateral vibrations of a cantilever. As a practical example, a cantilever with eight patch actuators under the influence of a tip-force is studied. It is found that the deflection at eight arbitrary points along the beam axis may be controlled independently, if the local action of the piezoelectric patches is equal in magnitude, but opposite in sign, to the external load. This is achieved by the proper design of the resistive network and a suitable choice of the input voltage signal. The validity of our method is exact in the static case for a Bernoulli-Euler beam, but it also gives satisfactory results at higher frequencies and for transient excitations. As long as a certain non-dimensional parameter, involving the number of the piezoelectric patches, the sum of the resistances in the electric network and the excitation frequency, is small, the proposed shape control method is approximately fulfilled for dynamic load excitations. We evaluate the feasibility of the proposed shape control method with a more refined model, by comparing the results of our one-dimensional calculations based on the extended Bernoulli-Euler equations to three-dimensional electromechanically coupled finite element results in ANSYS 12.0. The results with the simple Bernoulli-Euler model agree well with the three-dimensional finite element results.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001819361
|
oai_dc
|
Design of piezoelectric transducer arrays for passive and active modal control of thin plates
|
Design of piezoelectric transducer arrays for passive and active modal control of thin plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Georg Zenz(Linz Center of Mechatronics (LCM)); Michael Krommer(Johannes Kepler University Linz); Wolfgang Berger(Linz Center of Mechatronics (LCM)); Johannes Gerstmayr(Linz Center of Mechatronics (LCM)); Manfred Nader(Linz Center of Mechatronics (LCM))"
] |
To suppress vibration and noise of mechanical structures piezoelectric ceramics play an increasing role as effective, simple and light-weighted damping devices as they are suitable for sensing and actuating. Out of the various piezoelectric damping methods this paper compares mode based active control strategies to passive shunt damping for thin plates. Therefore, a new approach for the optimal placement of the piezoelectric sensors/actuators, or more general transducers, is proposed after intense theoretical investigations based on the Kirchhoff kinematical hypotheses of plates; in particular, modal and nilpotent transducers are discussed in detail. Based on the proposed distribution a discrete design for modal transducers is implemented, tested and verified on an experimental setup. For active control the modal sensors clearly identify the eigenmodes, whereas the modal actuators impose distributed eigenstrains in order to reduce the transverse plate vibrations. In contrast to the modal control, passive shunt damping works without requiring additional actuators or auxiliary power and can therefore act as an autonomous system, but it is less effective compensating the flexible vibrations. Exemplarily, an acryl glass plate disturbed by an arbitrary force initialized by a loudspeaker is investigated. Comparing the different methods their specific advantages are highlighted and a significant broadband reduction of the vibrations of up to -20dB is obtained.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001819357
|
oai_dc
|
Piezoceramic d15 shear–induced direct torsion actuation mechanism: a new representative experimental benchmark
|
Piezoceramic d15 shear–induced direct torsion actuation mechanism: a new representative experimental benchmark
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pelin Berik(Johannes Kepler University); Ayech Benjeddou(Institut Supérieur de Mécanique de Paris); Michael Krommer(Johannes Kepler University)"
] |
A new piezoceramic d15 shear-induced torsion actuation mechanism representative benchmark is proposed and its experimentations and corresponding 3D finite element (FE) simulations are conducted. For this purpose, a long and thin smart sandwich cantilever beam is dimensioned and built so that it can be used later for either validating analytical Saint Venant-type solutions or for analyzing arm or blade-based smart structures and systems applications. The sandwich beam core is formed by two adjacent rows of 8 oppositely axially polarized d15 shear piezoceramic patches, and its faces are dimensionally identical and made of the same glass fiber reinforced polymer composite material. Quasi-static and static experimentations were made using a point laser sensor and a scanning laser vibrometer, while the 3D FE simulations were conducted using the commercial software ABAQUS®. The measured transverse deflection by both sensors showed strong nonlinear and hysteretic (static only) variation with the actuation voltage, which cannot be caught by the linear 3D FE simulations.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001762598
|
oai_dc
|
Damage detction and characterization using EMI technique under varying axial load
|
Damage detction and characterization using EMI technique under varying axial load
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yee Yan Lim(University Malaysia Sabah); Chee Kiong Soh(Nanyang Technological University)"
] |
Recently, researchers in the field of structural health monitoring (SHM) have been rigorously striving to replace the conventional NDE techniques with the smart material based SHM techniques, employing smart materials such as piezoelectric materials. For instance, the electromechanical impedance (EMI) technique employing piezo-impedance (lead zirconate titanate, PZT) transducer is known for its sensitivity in detecting local damage. For practical applications, various external factors such as fluctuations of temperature and loading, affecting the effectiveness of the EMI technique ought to be understood and compensated. This paper aims at investigating the damage monitoring capability of EMI technique in the presence of axial stress with fixed boundary condition. A compensation technique using effective frequency shift (EFS) by cross-correlation analysis was incorporated to compensate the effect of loading and boundary stiffening. Experimental tests were conducted by inducing damages on lab-sized aluminium beams in the presence of tensile and compressive forces. Two types of damages, crack propagation and bolts loosening were simulated. With EFS for compensation, both cross-correlation coefficient (CC) index and reduction in peak frequency were found to be efficient in characterizing damages in the presence of varying axial loading.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001762600
|
oai_dc
|
Damage identification of isolators in base-isolated torsionally coupled buildings
|
Damage identification of isolators in base-isolated torsionally coupled buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jer-Fu Wang(National Museum of Natural Science); Chi-Chang Lin(National Chung Hsing University); Ming-Chih Huang(Air Force Institute of Technology); Tzu-Kang Lin(National Chiao Tung University)"
] |
This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001762601
|
oai_dc
|
Determination of stay cable force based on effective vibration length accurately estimated from multiple measurements
|
Determination of stay cable force based on effective vibration length accurately estimated from multiple measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chien-Chou Chen(National Yunlin University of Science and Technology); Wen-Hwa Wu(National Yunlin University of Science and Technology); Chin-Hui Huang(National Yunlin University of Science and Technology); Gwolong Lai(National Yunlin University of Science and Technology)"
] |
Due to its easy operation and wide applicability, the ambient vibration method is commonly adopted to determine the cable force by first identifying the cable frequencies from the vibration signals. With given vibration length and flexural rigidity, an analytical or empirical formula is then used with these cable frequencies to calculate the cable force. It is, however, usually difficult to decide the two required parameters, especially the vibration length due to uncertain boundary constraints. To tackle this problem, a new concept of combining the modal frequencies and mode shape ratios is fully explored in this study for developing an accurate method merely based on ambient vibration measurements. A simply supported beam model with an axial tension is adopted and the effective vibration length of cable is then independently determined based on the mode shape ratios identified from the synchronized measurements. With the effective vibration length obtained and the identified modal frequencies, the cable force and flexural rigidity can then be solved using simple linear regression techniques. The feasibility and accuracy of the proposed method is extensively verified with demonstrative numerical examples and actual applications to different cable-stayed bridges. Furthermore, several important issues in engineering practice such as the number of sensors and selection of modes are also thoroughly investigated.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001762597
|
oai_dc
|
Wavelet based multi-step filtering method for bridge health monitoring using GPS and accelerometer
|
Wavelet based multi-step filtering method for bridge health monitoring using GPS and accelerometer
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology, Tongji University, South China University of Technology); Hong-Nan Li(Dalian University of Technology); Ming Gu(Tongji University)"
] |
Effective monitoring, reliable data analysis, and rational data interpretations are challenges for engineers who are specialized in bridge health monitoring. This paper demonstrates how to use the Global Positioning System (GPS) and accelerometer data to accurately extract static and quasi-static displacements of the bridge induced by ambient effects. To eliminate the disadvantages of the two separate units, based on the characteristics of the bias terms derived from the GPS and accelerometer respectively, a wavelet based multi-step filtering method by combining the merits of the continuous wavelet transform (CWT) with the discrete stationary wavelet transform (SWT) is proposed so as to address the GPS deformation monitoring application more efficiently. The field measurements are carried out on an existing suspension bridge under the normal operation without any traffic interference. Experimental results showed that the frequencies and absolute displacements of the bridge can be accurate extracted by the proposed method. The integration of GPS and accelerometer can be used as a reliable tool to characterize the dynamic behavior of large structures such as suspension bridges undergoing environmental loads.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001762599
|
oai_dc
|
Bridge deflection evaluation using strain and rotation measurements
|
Bridge deflection evaluation using strain and rotation measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Helder Sousa(Universidade do Porto); Filipe Cavadas(Universidade do Porto); Abel Henriques(Universidade do Porto); Joaquim Figueiras(Universidade do Porto); João Bento(Instituto Superior Técnico)"
] |
Monitoring systems currently applied to concrete bridges include strain gauges, inclinometers,accelerometers and displacement transducers. In general, vertical displacements are one of the parameters that more often need to be assessed because their information reflects the overall response of the bridge span.
However, the implementation of systems to continuously and directly observe vertical displacements is known to be difficult. On the other hand, strain gauges and inclinometers are easier to install, but their measurements provide no more than indirect information regarding the bridge deflection.
In this context, taking advantage of the information collected through strain gauges and inclinometers, and the processing capabilities of current computers, a procedure to evaluate bridge girder deflections based on polynomial functions is presented. The procedure has been implemented in an existing software system –MENSUSMONITOR –, improving the flexibility in the data handling and enabling faster data processing by means of real time visualization capabilities. Benefiting from these features, a comprehensive analysis aiming at assessing the suitability of polynomial functions as an approximate solution for deflection curves,is presented. The effect of boundary conditions and the influence of the order of the polynomial functions on the accuracy of results are discussed. Some recommendations for further instrumentation plans are provided based on the results of the present analysis. This work is supported throughout by monitoring data collected from a laboratory beam model and two full-scale bridges.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695169
|
oai_dc
|
Energy harvesting and power management of wireless sensors for structural control applications in civil engineering
|
Energy harvesting and power management of wireless sensors for structural control applications in civil engineering
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sara Casciati(University of Catania); Zhicong Chen(University of Pavia); Lucia Faravelli(University of Pavia)"
] |
The authors’ research efforts recently led to the development of a customized wireless control unit which receives the real-time feedbacks from the sensors, and elaborates the consequent control signal to drive the actuator(s). The controller is wireless in performing the data transmission task, i.e., it receives the signals from the sensors without the need of installing any analogue cable connection between them, but it is powered by wire. The actuator also needs to be powered by wire. In this framework, the design of a power management unit is of interest only for the wireless sensor stations, and it should be adaptable to different kind of sensor requirements in terms of voltage and power consumption. In the present paper, the power management efficiency is optimized by taking into consideration three different kinds of accelerometers, a load cell, and a non-contact laser displacement sensor. The required voltages are assumed to be provided by a power harvesting solution where the energy is stored into a capacitor.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695150
|
oai_dc
|
Energy-efficiency enhancement and displacement-offset elimination for hybrid vibration control
|
Energy-efficiency enhancement and displacement-offset elimination for hybrid vibration control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kanjuro Makihara(Tohoku University)"
] |
New insights into our previously proposed hybrid-type method for vibration control are highlighted in terms of energy analysis, such as the assessment of energy efficiency and system stability. The hybrid method improves the bang-bang active method by combining it with an energy-recycling approach. Its simple configuration and low energy-consumption property are quite suitable especially for isolated structures whose energy sources are strictly limited. The harmful influence of the external voltage is assessed, as well as its beneficial performance. We show a new chattering prevention approach that both harvests electrical energy from piezoelectric actuators and eliminates the displacement-offset of the equilibrium point of structures. The amount of energy consumption of the hybrid system is assessed qualitatively and is compared with other control systems. Experiments and numerical simulations conducted on a 10-bay truss can provide a thorough energy-efficiency evaluation of the hybrid suppression system having our energy-harvesting system.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695156
|
oai_dc
|
A versatile software architecture for civil structure monitoring with wireless sensor networks
|
A versatile software architecture for civil structure monitoring with wireless sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kallirroi Flouri(Empa Dübendorf); Olga Saukh(ETH Zürich); Robert Sauter(University of Duisburg-Essen); Khash Erdene Jalsan(Empa Dübendorf); Reinhard Bischoff(Decentlab GmbH); Jonas Meyer(Decentlab GmbH); Glauco Feltrin(Empa Dübendorf)"
] |
Structural health monitoring with wireless sensor networks has received much attention in recent years due to the ease of sensor installation and low deployment and maintenance costs. However, sensor network technology needs to solve numerous challenges in order to substitute conventional systems: large amounts of data, remote configuration of measurement parameters, on-site calibration of sensors and robust networking functionality for long-term deployments. We present a structural health monitoring network that addresses these challenges and is used in several deployments for monitoring of bridges and buildings. Our system supports a diverse set of sensors, a library of highly optimized processing algorithms and a lightweight solution to support a wide range of network runtime configurations. This allows flexible partitioning of the application between the sensor network and the backend software. We present an analysis of this partitioning and evaluate the performance of our system in three experimental network deployments on civil structures.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695168
|
oai_dc
|
WiSeMote: a novel high fidelity wireless sensor network for structural health monitoring
|
WiSeMote: a novel high fidelity wireless sensor network for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Davis P. Hoover(Texas Tech University); Jennifer A. Rice(University of Florida); Argenis Bilbao(Texas Tech University)"
] |
Researchers have made significant progress in recent years towards realizing effective structural health monitoring (SHM) utilizing wireless smart sensor networks (WSSNs). These efforts have focused on improving the performance and robustness of such networks to achieve high quality data acquisition and distributed, in-network processing. One of the primary challenges still facing the use of smart sensors for longterm monitoring deployments is their limited power resources. Periodically accessing the sensor nodes to change batteries is not feasible or economical in many deployment cases. While energy harvesting techniques show promise for prolonging unattended network life, low power design and operation are still critically important. This research presents the WiSeMote: a new, fully integrated ultra-low power wireless smart sensor node and a flexible base station, both designed for long-term SHM deployments. The power consumption of the sensor nodes and base station has been minimized through careful hardware selection and the implementation of power-aware network software, without sacrificing flexibility and functionality.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695165
|
oai_dc
|
A split spectrum processing of noise-contaminated wave signals for damage identification
|
A split spectrum processing of noise-contaminated wave signals for damage identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.T. Miao(Shanghai Jiao Tong University); F.C. Li(Shandong Agricultural University); Lin Ye(The University of Sydney); X.W. Sun(Shanghai Jiao Tong University); H.K. Peng(Shanghai Institute of Satellite Engineering); Ye Lu(The University of Sydney); Guang Meng(Shanghai Jiao Tong University)"
] |
A split spectrum processing (SSP) method is proposed to accurately determine the time-of-flight (ToF) of damage-scattered waves by comparing the instantaneous amplitude variation degree (IAVD) of a wave signal captured from a damage case with that from the benchmark. The fundamental symmetrical (S0) mode in aluminum plates without and with a notch is assessed. The efficiency of the proposed SSP method and Hilbert transform in determining the ToF of damage-scattered S0 mode is evaluated for damage identification when the wave signals are severely contaminated by noise. Broadband noise can overwhelm damage-scattered wave signals in the time domain, and the Hilbert transform is only competent for determining the ToF of damage-scattered S0 mode in a noise-free condition. However, the calibrated IAVD of the captured wave signal is minimally affected by noise, and the proposed SSP method is capable of determining the ToF of damage-scattered S0 mode accurately even though the captured wave signal is severely contaminated by broadband noise, leading to the successful identification of damage (within an error on the order of the damage size) using a triangulation algorithm.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001695160
|
oai_dc
|
Computational aspects of guided wave based damage localization algorithms in flat anisotropic structures
|
Computational aspects of guided wave based damage localization algorithms in flat anisotropic structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jochen Moll(Goethe University of Frankfurt); Miguel Angel Torres-Arredondo(University of Siegen); Claus-Peter Fritzen(University of Siegen)"
] |
Guided waves have shown a great potential for structural health monitoring (SHM) applications. In contrast to traditional non-destructive testing (NDT) methodologies, a key element of SHM approaches is the high process of automation. The monitoring system should decide autonomously whether the host structure is intact or not. A basic requirement for the realization of such a system is that the sensors are permanently installed on the host structure. Thus, baseline measurements become available that can be used for diagnostic purposes, i.e., damage detection, localization, etc. This paper contributes to guided wave-based inspection in anisotropic materials for SHM purposes. Therefore, computational strategies are described for both, the solution of the complex equations for wave propagation analysis in composite materials based on exact elasticity theory and the popular global matrix method, as well as the underlying equations of two active damage localization algorithms for anisotropic structures. The result of the global matrix method is an angular and frequency dependent wave velocity characteristic that is used subsequently in the localization procedures.
Numerical simulations and experimental investigations through time-delay measurements are carried out in order to validate the proposed theoretical model. An exemplary case study including the calculation of dispersion curves and damage localization is conducted on an exemplary unidirectional composite structure where the ultrasonic signals processed in the localization step are simulated with the spectral element method.
The proposed study demonstrates the capabilities of the proposed algorithms for accurate damage localization in anisotropic structures.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711938
|
oai_dc
|
SHM benchmark for high-rise structures: a reduced-order finite element model and field measurement data
|
SHM benchmark for high-rise structures: a reduced-order finite element model and field measurement data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.Q. Ni(The Hong Kong Polytechnic University); Y. Xia(The Hong Kong Polytechnic University); W. Lin(The Hong Kong Polytechnic University); W.H. Chen(The Hong Kong Polytechnic University); J.M. Ko(The Hong Kong Polytechnic University)"
] |
The Canton Tower (formerly named Guangzhou New TV Tower) of 610 m high has been instrumented with a long-term structural health monitoring (SHM) system consisting of over 700 sensors of sixteen types. Under the auspices of the Asian-Pacific Network of Centers for Research in Smart Structures Technology (ANCRiSST), an SHM benchmark problem for high-rise structures has been developed by taking the instrumented Canton Tower as a host structure. This benchmark problem aims to provide an international platform for direct comparison of various SHM-related methodologies and algorithms with the use of realworld monitoring data from a large-scale structure, and to narrow the gap that currently exists between the research and the practice of SHM. This paper first briefs the SHM system deployed on the Canton Tower, and the development of an elaborate three-dimensional (3D) full-scale finite element model (FEM) and the validation of the model using the measured modal data of the structure. In succession comes the formulation of an equivalent reduced-order FEM which is developed specifically for the benchmark study. The reducedorder FEM, which comprises 37 beam elements and a total of 185 degrees-of-freedom (DOFs), has been elaborately tuned to coincide well with the full-scale FEM in terms of both modal frequencies and mode shapes. The field measurement data (including those obtained from 20 accelerometers, one anemometer and one temperature sensor) from the Canton Tower, which are available for the benchmark study, are subsequently presented together with a description of the sensor deployment locations and the sensor specifications.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711941
|
oai_dc
|
Finite element model updating of Canton Tower using regularization technique
|
Finite element model updating of Canton Tower using regularization technique
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Truong Thanh Chung(KAIST); Chung Bang Yun(UNIST); 조수진(University of Illinois at Urbana-Champaign); 손훈(KAIST)"
] |
This paper summarizes a study for the modal analysis and model updating conducted using the monitoring data obtained from the Canton Tower of 610 m tall, which was established as an international benchmark problem by the Hong Kong Polytechnic University. Modal properties of the tower were successfully identified using frequency domain decomposition and stochastic subspace identification methods. Finite element model updating using the measurement data was further performed to reduce the modal property differences between the measurements and those of the finite element model. Over-fitting during the model updating was avoided by using an optimization scheme with a regularization term.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711942
|
oai_dc
|
Update the finite element model of Canton Tower based on direct matrix updating with incomplete modal data
|
Update the finite element model of Canton Tower based on direct matrix updating with incomplete modal data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. Lei(Xiamen University); H.F. Wang(Xiamen University); W.A. Shen(The Hong Kong Polytechnic University)"
] |
In this paper, the structural health monitoring (SHM) benchmark problem of the Canton tower is studied. Based on the field monitoring data from the 20 accelerometers deployed on the tower, some modal frequencies and mode shapes at measured degrees of freedom of the tower are identified. Then, these identified incomplete modal data are used to update the reduced finite element (FE) model of the tower by a novel algorithm. The proposed algorithm avoids the problem of subjective selection of updated parameters and directly updates model stiffness matrix without model reduction or modal expansion approach. Only the eigenvalues and eigenvectors of the normal finite element models corresponding to the measured modes are needed in the computation procedures. The updated model not only possesses the measured modal frequencies and mode shapes but also preserves the modal frequencies and modes shapes in their normal values for the unobserved modes. Updating results including the natural frequencies and mode shapes are compared with the experimental ones to evaluate the proposed algorithm. Also, dynamic responses estimated from the updated FE model using remote senor locations are compared with the measurement ones to validate the convergence of the updated model.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711940
|
oai_dc
|
Information entropy based algorithm of sensor placement optimization for structural damage detection
|
Information entropy based algorithm of sensor placement optimization for structural damage detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.Q. Ye(The Hong Kong Polytechnic University); Y. Q. Ni(The Hong Kong Polytechnic University)"
] |
The structural health monitoring (SHM) benchmark study on optimal sensor placement problem for the instrumented Canton Tower has been launched. It follows the success of the modal identification and model updating for the Canton Tower in the previous benchmark study, and focuses on the optimal placement of vibration sensors (accelerometers) in the interest of bettering the SHM system. In this paper, the sensor placement problem for the Canton Tower and the benchmark model for this study are first detailed. Then an information entropy based sensor placement method with the purpose of damage detection is proposed and applied to the benchmark problem. The procedure that will be implemented for structural damage detection using the data obtained from the optimal sensor placement strategy is introduced and the information on structural damage is specified. The information entropy based method is applied to measure the uncertainties throughout the damage detection process with the use of the obtained data. Accordingly, a multi-objective optimal problem in terms of sensor placement is formulated. The optimal solution is determined as the one that provides equally most informative data for all objectives, and thus the data obtained is most informative for structural damage detection. To validate the effectiveness of the optimally determined sensor placement,damage detection is performed on different damage scenarios of the benchmark model using the noise-free and noise-corrupted measured information, respectively. The results show that in comparison with the existing inservice sensor deployment on the structure, the optimally determined one is capable of further enhancing the capability of damage detection.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711943
|
oai_dc
|
Mode shape expansion with consideration of analytical modelling errors and modal measurement uncertainty
|
Mode shape expansion with consideration of analytical modelling errors and modal measurement uncertainty
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hua-Peng Chen(University of Greenwich); Kong Fah Tee(University of Greenwich); Yi-Qing Ni(The Hong Kong Polytechnic University)"
] |
Mode shape expansion is useful in structural dynamic studies such as vibration based structural health monitoring; however most existing expansion methods can not consider the modelling errors in the finite element model and the measurement uncertainty in the modal properties identified from vibration data. This paper presents a reliable approach for expanding mode shapes with consideration of both the errors in analytical model and noise in measured modal data. The proposed approach takes the perturbed force as an unknown vector that contains the discrepancies in structural parameters between the analytical model and tested structure. A regularisation algorithm based on the Tikhonov solution incorporating the L-curve criterion is adopted to reduce the influence of measurement uncertainties and to produce smooth and optimised expansion estimates in the least squares sense. The Canton Tower benchmark problem established by the Hong Kong Polytechnic University is then utilised to demonstrate the applicability of the proposed expansion approach to the actual structure. The results from the benchmark problem studies show that the proposed approach can provide reliable predictions of mode shape expansion using only limited information on the operational modal data identified from the recorded ambient vibration measurements.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001711939
|
oai_dc
|
Updating finite element model using dynamic perturbation method and regularization algorithm
|
Updating finite element model using dynamic perturbation method and regularization algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hua-Peng Chen(University of Greenwich); Tian-Li Huang(University of Greenwich)"
] |
An effective approach for updating finite element model is presented which can provide reliable estimates for structural updating parameters from identified operational modal data. On the basis of the dynamic perturbation method, an exact relationship between the perturbation of structural parameters such as stiffness change and the modal properties of the tested structure is developed. An iterative solution procedure is then provided to solve for the structural updating parameters that characterise the modifications of structural parameters at element level, giving optimised solutions in the least squares sense without requiring an optimisation method. A regularization algorithm based on the Tikhonov solution incorporating the generalised cross-validation method is employed to reduce the influence of measurement errors in vibration modal data and then to produce stable and reasonable solutions for the structural updating parameters. The Canton Tower benchmark problem established by the Hong Kong Polytechnic University is employed to demonstrate the effectiveness and applicability of the proposed model updating technique. The results from the benchmark problem studies show that the proposed technique can successfully adjust the reduced finite element model of the structure using only limited number of frequencies identified from the recorded ambient vibration measurements.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001705872
|
oai_dc
|
Operational modal analysis for Canton Tower
|
Operational modal analysis for Canton Tower
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yan Niu(University of Siegen); Claus-Peter Fritzen(University of Siegen); Peter Kraemer(Woelfel Beratende Ingenieure)"
] |
The 610 m high Canton Tower (formerly named Guangzhou New Television Tower) is currently considered as a benchmark problem for structural health monitoring (SHM) of high-rise slender structures. In the benchmark study task I, a set of 24-hour ambient vibration measurement data has been available for the output-only system identification study. In this paper, the vector autoregressive models (ARV) method is adopted in the operational modal analysis (OMA) for this TV tower. The identified natural frequencies, damping ratios and mode shapes are presented and compared with the available results from some other research groups which used different methods, e.g., the data-driven stochastic subspace identification (SSIDATA) method, the enhanced frequency domain decomposition (EFDD) algorithm, and an improved modal identification method based on NExT-ERA technique. Furthermore, the environmental effects on the estimated modal parameters are also discussed.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001705715
|
oai_dc
|
Modal identification of Canton Tower under uncertain environmental conditions
|
Modal identification of Canton Tower under uncertain environmental conditions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xijun Ye(South China University of Technology); Quansheng Yan(South China University of Technology); Weifeng Wang(South China University of Technology); Xiaolin Yu(South China University of Technology)"
] |
The instrumented Canton Tower is a 610 m high-rise structure, which has been considered as a benchmark problem for structural health monitoring (SHM) research. In this paper, an improved automatic modal identification method is presented based on a natural excitation technique in conjunction with the eigensystem realization algorithm (NExT/ERA). In the proposed modal identification method, damping ratio, consistent mode indicator from observability matrices (CMI_O) and modal amplitude coherence (MAC) are used as criteria to distinguish the physically true modes from spurious modes. Enhanced frequency domain decomposition (EFDD), the data-driven stochastic subspace identification method (SSI-DATA) and the proposed method are respectively applied to extract the modal parameters of the Canton Tower under different environmental conditions. Results of modal parameter identification based on output-only measurements are presented and discussed. User-selected parameters used in those methods are suggested and discussed. Furthermore, the effect of environmental conditions on the dynamic characteristics of Canton tower is investigated.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001705871
|
oai_dc
|
Structural health monitoring of Canton Tower using Bayesian framework
|
Structural health monitoring of Canton Tower using Bayesian framework
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sin-Chi Kuok(University of Macau); Ka-Veng Yuen(University of Macau)"
] |
This paper reports the structural health monitoring benchmark study results for the Canton Tower using Bayesian methods. In this study, output-only modal identification and finite element model updating are considered using a given set of structural acceleration measurements and the corresponding ambient conditions of 24 hours. In the first stage, the Bayesian spectral density approach is used for output-only modal identification with the acceleration time histories as the excitation to the tower is unknown. The modal parameters and the associated uncertainty can be estimated through Bayesian inference. Uncertainty quantification is important for determination of statistically significant change of the modal parameters and for weighting assignment in the subsequent stage of model updating. In the second stage, a Bayesian model updating approach is utilized to update the finite element model of the tower. The uncertain stiffness parameters can be obtained by minimizing an objective function that is a weighted sum of the square of the differences (residuals) between the identified modal parameters and the corresponding values of the model. The weightings distinguish the contribution of different residuals with different uncertain levels. They are obtained using the Bayesian spectral density approach in the first stage. Again, uncertainty of the stiffness parameters can be quantified with Bayesian inference. Finally, this Bayesian framework is applied to the 24- hour field measurements to investigate the variation of the modal and stiffness parameters under changing ambient conditions. Results show that the Bayesian framework successfully achieves the goal of the first task of this benchmark study.
|
토목공학
| null |
kci_detailed_000090.xml
|
|||
ART001705712
|
oai_dc
|
Sensor placement for structural health monitoring of Canton Tower
|
Sensor placement for structural health monitoring of Canton Tower
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology); Hong-Nan Li(Dalian University of Technology); Ming Gu(Tongji University)"
] |
A challenging issue in design and implementation of an effective structural health monitoring (SHM) system is to determine where a number of sensors are properly installed. In this paper, research on the optimal sensor placement (OSP) is carried out on the Canton Tower (formerly named Guangzhou New Television Tower) of 610 m high. To avoid the intensive computationally-demanding problem caused by tens of thousands of degrees of freedom (DOFs) involved in the dynamic analysis, the three dimension finite element (FE) model of the Canton Tower is first simplified to a system with less DOFs. Considering that the sensors can be physically arranged only in the translational DOFs of the structure, but not in the rotational DOFs, a new method of taking the horizontal DOF as the master DOF and rotational DOF as the slave DOF, and reducing the slave DOF by model reduction is proposed. The reduced model is obtained by IIRS method and compared with the models reduced by Guyan, Kuhar, and IRS methods. Finally, the OSP of the Canton Tower is obtained by a kind of dual-structure coding based generalized genetic algorithm (GGA).
|
토목공학
| null |
kci_detailed_000091.xml
|
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