A numerical method for calculating stress intensity factors for interface cracks in bimaterials

This paper presents a method For obtaining the complex stress intensity factor (or alternatively the corresponding energy release rate and mode mixity) for an interface crack in a bimaterial using a minimum number of computations. A crack closure integral method for homogeneous materials developed by Rybicki and Kanninen has been modified to include mismatch in material properties. This was achieved directly from the nodal forces at the crack tip and the displacements near the tip as obtained from a finite element analysis using only four-node constant strain elements. Numerical calculations for tensile and mixed mode loading showed good agreement with results from corresponding analytical solutions. The main advantages of this method are that it is straightforward and easy to use and that the number of calculations needed to obtain the stress intensity Factors can be held to a minimum. (C) 2000 Elsevier Science Ltd. All rights reserved.