Wave damage interaction in metals and composites

In this paper, numerical and experimental investigations of wave damage interaction in metals and composites were conducted. The frequency and direction dependent complex-valued wave damage interaction coefficients (WDIC) were used to model the scattering and mode conversion phenomena of guided wave interaction with damage. These coefficients were extracted from the harmonic analysis of small-size finite element (FE) model with non-reflective boundaries (NRB) and they are capable of describing the amplitude and phase of the scattered waves as a function of frequency and direction. Commercial finite element package ANSYS 17.0 was used to implement and realize the small-size FE model. First, the proposed method was used to extract the WDIC of a through hole in an aluminum plate. Then, the FEM WDIC was compared with the analytical model of A0 wave scattering at through hole, and the experimental validation was performed using scanning laser Doppler vibrometer (SLDV) measurements on an aluminum plate. It is shown that a good agreement between FEM WDIC and experimental WDIC is achieved. Finally, the harmonic analysis of small-size FE models was extended to extract the WDIC of composites. Through hole and delamination in a unidirectional composite plate were investigated. It can be observed that the scattering energy is mainly concentrated in the fiber directions when the A0 waves interact with the through hole.