Analysis on delamination-induced variations of modal parameters in multi-layer composites

A feasibility study on the use of modal parameter analysis for location prediction of damage in composites is conducted. In order to investigate the relationship between delamination location and change of modal parameter, the finite element method for the multi-layer composite plates with different delaminations are adopted. Natural frequencies and mode shapes are computed and their variations induced by delaminations at different positions are analyzed. The numerical result is in better agreement with experiment result than that of reference. The mechanism of the mode-dependent energy dissipation of composite plates due to delamination is revealed for the first time. The result allows of the establishment, of guideline for location identification of damage.