Analytical derivation and investigation of the interface crack models

The oscillating and the contact zone models are derived from the exact solution of the plane problem for an interface crack with contact zone of arbitrary length and procedure of transition from one model to another is demonstrated. The transcendental equations and approximate relations for the contact zone length determination in terms of the stress intensity factors of the oscillating model are found and the examples of these relations utilization are presented. The energy release rate (ERR) for both models are given in simple analytical form and slight difference between them tbr any contact zone length is found out. Quasi-invariance of the ERR with respect to contact zone length for any load and material properties is proved and a simple way of the ERR numerical determination is suggested. ;(~) 1998 Elsevier Science Ltd. All rights reserved