Identifying the location of a sudden damage in composite laminates using wavelet approach

by Salehian, Armaghan.

This study presents a general approach for an inverse problem to locate a sudden structural damage in a plate. The sudden damage is modeled as an impulse load and response data are collected at various sensor locations. In this simulation study the response data were generated by the commercial finite element code ANSYS for three square plates: one is an isotropic plate and made of aluminum and the others are two different composite plates made of graphite-epoxy. All plates are simply supported along all their edges. The responses of these plates to both narrow band and wide band loading were analyzed by a wavelet transform. The wavelet coefficient maps for each type of signal was utilized to estimate the shortest path arrival times of flexural waves resulted from the damage by locating the wavelet coefficient peak values of the response data. Using the dispersion relations of wave propagation based on the Mindlin’s plate theory, a set of nonlinear equations were derived to solve this inverse problem and the location of the applied load, which models a structural damage, was determined. The estimated locations for all different types of plates have shown an excellent agreement with the actual location of the impact loads applied. 1