Abstract
First, the concepts of separated dynamic J integral and separated energy release rate were presented for dynamic interfacial fracture mechanics. The separated dynamic J integral has the physical meaning of the energy flow rate to a propagating interfacial crack tip from each material component. Next, a moving finite element method for dynamic interfacial fracture analysis was developed to make it possible to analyze transonic and supersonic interfacial crack propagation. The moving finite element simulations revealed the shock waves(Mach waves)emanated from transonically and supersonically propagating crack tips. The dynamic J integral and the separated dynamic J integrals showed excellent path independence for all crack-velocity regimes even for supersonic interfacial crack propagation. It was found that, in the subsonic crack-velocity-regimes, the compliant material supplies larger fracture energy than the stiff material does. From the energy flow rate to the propagating interfacial crack tip, the theoretical limit of interfacial crack velocity without macrocontact zone was found to be the shear wave velocity of the compliant material.
