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Interaction and Multiscale Mechanics   Volume 3, Number 4, December 2010, pages 321-331
DOI: https://doi.org/10.12989/imm.2010.3.4.321
 
Identification of beam crack using the dynamic response of a moving spring-mass unit
Ning An, He Xia and Jiawang Zhan

 
Abstract     [Buy Article]
    A new technique is proposed for bridge structural damage detection based on spatial wavelet analysis of the time history obtained from vehicle body moving over the bridge, which is different from traditional detection techniques based on the bridge response. A simply-supported Bernoulli-Euler beam subjected to a moving spring-mass unit is established, with the crack in the beam simulated by modeling the cracked section as a rotational spring connecting two undamaged beam segments, and the equations of motion for the system is derived. By using the transfer matrix method, the natural frequencies and mode shapes of the cracked beam are determined. The responses of the beam and the moving spring-mass unit are obtained by modal decomposition theory. The continuous wavelet transform is calculated on the displacement time histories of the sprung-mass. The case study result shows that the damage location can be accurately determined and the method is effective.
 
Key Words
    moving load; beam; dynamic response; damage detection; wavelet transform; Lipschitz exponent.
 
Address
Ning An, He Xia and Jiawang Zhan: School of Civil Engineering, Beijing Jiaotong University, Beijing 10004, China
 

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