Evaluation of interlaminar adhesion strength of carbon fiber reinforced plastics with different molding pressure and fiber volume fraction by a laser spallation technique

Abstract

CFRP is a promising material in various industrial field due to its high specific strength. The interlaminar strength between layers in the CFRP is also important. In this study, the interlaminar strength of CFRP was evaluated with a laser spallation technique. The laser spallation technique allows to exfoliate the interface between the layers by strong longitudinal waves induced by a pulsed laser irradiation. Two cross-ply CFRP plates fabricated with different molding pressure of 0.1MPa (normal) and 0.01 MPa and fiber volume fraction (V_f) of 67% and a unidirectional CFRP with low V_f of 45% were prepared. The interlaminar strength of the low V_f sample was decreased by 20 MPa compared to that of the normal CFRP. The decrease in interlaminar strength was caused by the thicker resin rich area along the interfaces in low fiber volume fraction. On the other hand, the strength of the CFRP molded with the low pressure was the same as that with normal pressure.