Structural Health Monitoring and Damage Detection of Structures by Wavelet-Based Method

Wavelet transform is a new and useful method for signal analysis. Wavelet function is a composition of basic functions which can separate a signal in time and frequency. Therefore, wavelet transforms are capable of detecting many of unknown aspects of information which can not be detected through other methods. A wavelet-based nondestructive method for damage detection in structures that is effective and accurate is presented in this text. The proposed method is based on the analysis of the response signal of damaged structures. The main idea is to extract the damage location from the coefficients of the wavelet transform applying on the signals coming from the structural responses. After analysis of the structure by ABAQUS software, displacement response of structure was extracted along its longitudinal axis. Afterwards, the response was used for the wavelet analysis by the wavelet toolbox of the MATLAB software and the detection of damage in the structures was investigated. The results of wavelet analysis showed that the wavelet coefficients plots have considerable rise at or around the damage location. A sudden change or peak on the wavelet coefficients plot can indicate the location of a crack. Based on the obtained simulation results, it appears that this method can provide an advantageous alternative to classical methods for structural damage detection, such as Fourier transform.