Fracture parameters of interfacial crack of bimaterial under the impact loading

The impact responses of the fracture parameters of interfacial crack tip, s uch as energy release rate (J integral), stress intensity factors (K), crac k opening displacement (COD) and T stress, under the dynamic loading condit ion were studied using both numerical and experimental methods. A three poi nt bending impact test was performed with bimaterial specimens composed of aluminum and polymethyl methacrylate (PMMA). Fracture parameters for the in terfacial crack tip were calculated by a programmed post processor which us ed both the domain integral method and the interaction energy method. The i nteraction energy method showed good performance in the decomposition of st ress intensity factor and the calculation of elastodynamic T stress with pa th independency. The phase angle of stress intensity factor varied with tim e. The relationship between energy release rate and phase angle at the onse t of crack propagation showed unsymmetrical U shaped curve. COD showed same result with the result of stress intensity factors. The magnitude of the T stress was not enough to affect the plastic deformation. Specimens whose T stress were less than zero exhibited stable crack growth along the interfa ce as expected in the analysis. (C) 2001 Published by Elsevier Science Ltd.