抄録
A formulation was derived to evaluate the velocity of plate waves propagating in composite materials. The formulation was based on Mindlin plate theory including the effect of shear deformation and rotary inertia. The influence of thickness, stacking sequence and propagating direction on the wave velocity was investigated. The formulation was applied to identify delamination in composite materials. The plate waves propagating in GFRP with delamination on the mid-plane were detected with AE sensors. The time-frequency analysis of AE signals was carried out by the wavelet transform. The peaks of the magnitude of wavelet transform in the time-frequency domain were related to the arrival times of plate waves. The length of delamination was predicted from the arrival time of a certain frequency component of plate waves. The predicted length of delamination agreed well with the actual length.
