Stress Intensity Factors in Two Bonded Elastic Layers Containing Crack Perpendicular on the Interface with Different Elastic Properties

Abstract

Thin bonded films have many applications ( i.e . in information storage and processing systems, and etc.). In many cases, thin bonded films are in a state of residual tension, which can lead to film cracking and crack extension in one layer often accompanies failure in whole systems. In this paper, we analyze a channel crack advanced throughout thickness of an elastic thin film bonded to a dissimilar semi-infinite substrate material via finite element method (FEM). In order to simplify modeling, the problem is idealized as plane strain and a two-dimensional model of a film bonded to an elastic substrate is proposed for simulating channel crack in thin elastic film. Film is modeled by common 4-node and substrate by infinite 4-node meshes. The stress intensity factor (SIF) for cracked thin film has been obtained as a function of elastic mismatch between the substrate and the film. The results indicate that in elastic mismatch state, SIF is more than match state. On the other hand, mismatch state is more sensitive to crack than match state. And SIF has also increased by increasing Young’s modulus and Poisson ratio of film.