Damage detection for shear structures based on wavelet spectral transmissibility matrices under nonstationary stochastic excitation

A new method of spectral transmissibility function extraction and damage detection for shear frame structures under nonstationary stochastic excitation is proposed. A new concept named wavelet spectral transmissibility function is proposed as damage feature. It is demonstrated that the wavelet spectral transmissibility function can characterize the structure while closing to the natural frequencies of the structure. Subsequence, the singular value decomposition of wavelet spectral transmissibility matrices with different references is proposed as an identification method of natural frequencies, and wavelet spectral transmissibility functions between two neighborhood measurement points at the natural frequencies under nonstationary stochastic excitation. At last, a new damage indicator is developed to locate and quantify the damage of shear frame structure, based on the wavelet spectral transmissibility functions and constraint linear least square method. A numerical model and a lab-scale frame structure successfully verify the validity of the proposed algorithm. Copyright (C) 2016 John Wiley & Sons, Ltd.