Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

Duc-Duy Ho,Dong-Soo Hong,Jeong-Tae Kim 한국비파괴검사학회 2010 한국비파괴검사학회지 Vol.30 No.6

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified.

Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

Ho, Duc-Duy,Hong, Dong-Soo,Kim, Jeong-Tae The Korean Society for Nondestructive Testing 2010 한국비파괴검사학회지 Vol.30 No.6

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified.

Nondestructive crack detection in metal structures using impedance responses and artificial neural networks

Ho, Duc-Duy,Luu, Tran-Huu-Tin,Pham, Minh-Nhan Techno-Press 2022 Structural monitoring and maintenance Vol.9 No.3

Among nondestructive damage detection methods, impedance-based methods have been recognized as an effective technique for damage identification in many kinds of structures. This paper proposes a method to detect cracks in metal structures by combining electro-mechanical impedance (EMI) responses and artificial neural networks (ANN). Firstly, the theories of EMI responses and impedance-based damage detection methods are described. Secondly, the reliability of numerical simulations for impedance responses is demonstrated by comparing to pre-published results for an aluminum beam. Thirdly, the proposed method is used to detect cracks in the beam. The RMSD (root mean square deviation) index is used to alarm the occurrence of the cracks, and the multi-layer perceptron (MLP) ANN is employed to identify the location and size of the cracks. The selection of the effective frequency range is also investigated. The analysis results reveal that the proposed method accurately detects the cracks' occurrence, location, and size in metal structures.

Solar-powered multi-scale sensor node on Imote2 platform for hybrid SHM in cable-stayed bridge

Duc-Duy Ho,김정태,Khac-Duy Nguyen,홍동수,이소영,신성우,윤정방,Masanobu Shinozuka,Po-Young Lee 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.9 No.2

In this paper, solar-powered, multi-scale, vibration-impedance sensor node on Imote2 platform is presented for hybrid structural health monitoring (SHM) in cable-stayed bridge. In order to achieve the objective, the following approaches are proposed. Firstly, vibration- and impedance-based hybrid SHM methods are briefly described. Secondly, the multi-scale vibration and impedance sensor node on Imote2- platform is presented on the design of hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solar-powered energy harvesting is implemented for autonomous operation of the smart sensor nodes. Finally, the feasibility and practicality of the smart sensor-based SHM system is evaluated on a full-scale cable-stayed bridge, Hwamyung Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified. Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions are examined for the robust long-term monitoring capability of the smart sensor system.

Impedance-based damage monitoring of steel column connection: numerical simulation

Ho, Duc-Duy,Ngo, Thanh-Mong,Kim, Jeong-Tae Techno-Press 2014 Structural monitoring and maintenance Vol.1 No.3

This study has been motivated to evaluate the practicality of numerical simulation of impedance monitoring for damage detection in steel column connection. In order to achieve the objective, the following approaches are implemented. Firstly, the theory of electro-mechanical (E/M) impedance responses and impedance-based damage monitoring method are outlined. Secondly, the feasibility of numerical simulation of impedance monitoring is verified for several pre-published experimental examples on steel beams, cracked aluminum beams, and aluminum round plates. Undamaged and damaged steel and aluminum beams are simulated to compare to experimental impedance responses. An aluminum round plate with PZT patch in center is simulated to investigate sensitive range of impedance responses. Finally, numerical simulation of the impedance-based damage monitoring is performed for a steel column connection in which connection bolts are damaged. From the numerical simulation test, the applicability of the impedance-based monitoring to the target steel column connection can be evaluated.

Multi-Phase Model Update for System Identification of PSC Girders under Various Prestress Forces

Ho, Duc-Duy,Hong, Dong-Soo,Kim, Jeong-Tae Computational Structural Engineering Institute of 2010 한국전산구조공학회논문집 Vol.23 No.6

This paper presents a multi-phase model update approach for system identification of prestressed concrete (PSC) girders under various prestress forces. First, a multi-phase model update approach designed on the basis of eigenvalue sensitivity concept is newly proposed. Next, the proposed multi-phase approach is evaluated from controlled experiments on a lab-scale PSC girder for which forced vibration tests are performed for a series of prestress forces. On the PSC girder, a few natural frequencies and mode shapes are experimentally measured for the various prestress forces. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model which is established for the target PSC girder. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model update procedure. Based on model update results, the relationship between prestress forces and model-updating parameters is analyzed to evaluate the influence of prestress forces on structural subsystems.

Solar-powered multi-scale sensor node on Imote2 platform for hybrid SHM in cable-stayed bridge

Ho, Duc-Duy,Lee, Po-Young,Nguyen, Khac-Duy,Hong, Dong-Soo,Lee, So-Young,Kim, Jeong-Tae,Shin, Sung-Woo,Yun, Chung-Bang,Shinozuka, Masanobu Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.9 No.2

In this paper, solar-powered, multi-scale, vibration-impedance sensor node on Imote2 platform is presented for hybrid structural health monitoring (SHM) in cable-stayed bridge. In order to achieve the objective, the following approaches are proposed. Firstly, vibration- and impedance-based hybrid SHM methods are briefly described. Secondly, the multi-scale vibration and impedance sensor node on Imote2-platform is presented on the design of hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solar-powered energy harvesting is implemented for autonomous operation of the smart sensor nodes. Finally, the feasibility and practicality of the smart sensor-based SHM system is evaluated on a full-scale cable-stayed bridge, Hwamyung Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified. Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions are examined for the robust long-term monitoring capability of the smart sensor system.

진동기반 구조식별을 통한 프리스트레스트 콘크리트 거더의 긴장력 손실 검색 기법

호득유이(Duc-Duy Ho),김정태(Jeong-Tae Kim),홍동수(Dong-Soo Hong) 한국해양공학회 2010 韓國海洋工學會誌 Vol.24 No.1

This paper presents a prestress-loss monitoring technique for prestressed concrete (PSC) girder structures that uses a vibration-based system identification method. First, the theoretical backgrounds of the prestress-loss monitoring technique and the system identification technique are presented. Second, vibration tests are performed on a lab-scaled PSC girder for which the modal parameter was measured for several prestress-force cases. A numerical modal analysis is performed by using an initial finite element (FE) model from the geometric, material, and boundary conditions of the lab-scaled PSC girder. Third, a vibration-based system identification is performed to update the FE model by identifying structural parameters since the natural frequency of the FE model became identical to the experimental results. Finally, the feasibility of the prestress-loss monitoring technique is evaluated for the PSC girder model by using the experimentally measured natural frequency and numerically identified natural frequency for several prestress-force cases.

Damage detection in beam-type structures via PZT’s dual piezoelectric responses

Khac-Duy Nguyen,김정태,Duc-Duy Ho 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.2

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.

장대 사장교 케이블-앵커 부구조계의 진동-임피던스 기반 구조건전성 모니터링

이포영,Ho, Duc Duy,Nguyen, Khac Duy,김정태 한국구조물진단유지관리학회 2011 한국구조물진단학회 학술발표회논문집 Vol.2011 No.9

This study presents a vibration and impedance-based structural health monitoring (SHM) method for cable-anchorage subsystem in cable-stayed bridge. In order to achieve the objective, the following approaches are implemented. Firstly, a vibration-based cable force monitoring is described for the estimation of cable force by using acceleration signals measured from stayed cables. Secondly, an impedance-based cable force monitoring is presented for the monitoring of anchorage force using electro-mechanical impedance signatures are measured from anchorage subsystem. Finally, the performance of the vibration-impedance based SHM is evaluated for monitoring the change in cable force on cable-anchorage subsystem of full-scale cable-stayed bridge.