Numerical Model and Analysis on Dynamics of Composites for Active Damage Detection

This paper presents a study on active detection of internal damage based on numerical analysis of vibration dynamics in composites. Damageinduced variations of dynamic parameters are investigated both numerically and experimentally. Finite element method (FEM) is used to compute the modal parameters of composites with or without damages. Natural frequency, modal displacement, modal strain and strain energy are analyzed for the determination of damage severity and location. Vibration measurements are carried out using piezoelectric patch actuators and sensors for comparison and verification of the FEM model proposed in this study. Energy spectrum for wavelet packets decomposition of structural dynamic responses is used to highlight the features of damaged samples. The mechanism of mode-dependent energy dissipation of composite plates due to delamination is revealed for the first time. Both numerical and experimental findings in this study are significant to the establishment of guideline for damage identification in composite structures.