Stress Intensity Factors of a Mixed-Mode Interface Crack by a Finite Element Analysis.

Abstract

Two-dimensional finite element analysis has been carried out on compact tension and shear specimens under mixed-mode loading. The complex stress-intensity factor K associated with an elastic interface crack is discussed via three different approaches : virtual crack extension method, modified crack-closure integral and displacement extrapolation. A comparison of stress-intensity factors KI and KII obtained by these three methods is carried out. The accuracy of these methods is discussed for specimens comprised of various dissimilar materials under various kinds of mixed-mode loading. The accuracy of the virtual crack extension method was revealed by comparison with the J-integral. The modified crack-closure integral varies markedly depending on the mesh length at the crack tip. However, the stress-intensity factor can be estimated with high accuracy using an appropriate mesh length.