NUMERICAL SIMULATIONS OF DYNAMIC CRACK-GROWTH ALONG AN INTERFACE

Dynamic crack growth is analyzed numerically for a plane strain bimate rial block with an initial central crack. The material on each side of the bond line is characterized by an isotropic hyperelastic constitut ive relation. A cohesive surface constitutive relation is also specifi ed that relates the tractions and displacement jumps across the bond l ine and that allows for the creation of new free surface. The resistan ce to crack initiation and the crack speed history are predicted witho ut invoking any ad hoc failure criterion. Full finite strain transient analyses are carried out, with two types of loading considered; tensi le loading on one side of the specimen and crack face loading. The cra ck speed history and the evolution of the crack tip stress state are i nvestigated for parameters characterizing a PMMP/Al bimaterial. Additi onally, the separate effects of elastic modulus mismatch and elastic w ave speed mismatch on interface crack growth are explored for various PMMA-artificial material combinations. The mode mixity of the near tip fields is found to increase with increasing crack speed and in some c ases large scale contact occurs in the vicinity of the crack tip. Crac k speeds that exceed the smaller of the two Rayleigh wave speeds are a lso found.