Application of damage locating vectors approach on monitoring shock isolation system

Abstract

Structural damage detection based on the changes of dynamic properties is a major topic for structural health monitoring. In this paper, efforts are made to extend the flexibility-based damage localization methods, especially the damage locating vectors (DLVs) method, to the case of earthquake vibration, where the finite element model and mass matrices are not available. First, a new method using continuous Cauchy wavelet transform (CCWT) and ARX (autoregressive with exogenous input) model is applied to identify the modal parameters of a five-storey steel frame with seismic base isolation system LRB from its simulated acceleration responses under 10% and 100% of Chi-Chi Earthquake excitation (Taiwan, 1999). The DLVs, which determined from the change of flexibility matrix between two cases, are then used to monitor the shock isolation device in the structure through a weighted relative displacement index (WRDI). The proposed scheme is also proved to be superior to mode shape based methods (MAC, COMAC) in monitoring shock isolation system.