关键词: 热塑性复合材料, 层间断裂韧性, 非线性能量释放率

Abstract: The mode 1 inierlaminar fracture toughness of a new thermoplastic composite T300/PEK-C is investigated in this paper. The hinged double cantilever beam specimen is used to test Inierlaminar fracture toughness. The load-displacement curve appears nonlinear before unstable deiamination growth. This is caused mainly by matrix plasticity near crack tip. In order to evaluate interlaminar fracture properties of thermoplastic composite laminates correctly, the nonliner energy release rate G1C is defined which is taken as the interlaminar fracture toughness of thermoplastic composite, and the nonlinear correction and modified energy area integration methods are adopted to calculate G 1C. The results indicate that the values of G calculated by nonlinear correction method are in good agreement with those from modified area method and both of them are about ten percent higher than the results obtained by linear compliance and area methods. But the interlaminar fracture toughness of composite T300/PEK-C is only half of the fracture toughness of the matrix. The SEM photos show that the reason for low interlaminar fracture toughness is the poor interface strength In addition, the G1C of composite T300/PEK-C decreases with increase in loading speed, and under coordinates of G 1C and logarithmic loading speed a linare relation is shown. The SEM micrograph shows that its mechanism is the tough-brittle transform of matrix.

Key words: thermoplastic composite, interlaminar fi-ac, ure toughness, nonlinear energy release