Finite element calculation of stress intensity factors for interface notches

A least-squares method was developed to find the stress intensity factors (SIFs) of a notch formed from several elastic anisotropic materials. First, the complex displacement and stress functions of the interface notch are deduced into a simple matrix form, and then stress fields from the finite element analysis are substituted into the least-squares equation generated from the stress functions to evaluate the notch SIFs. Comparisons with theoretical and H-integral solutions indicate that the SIFs evaluated from the least-squares method are accurate if each dimension (two- or three-dimension) contains more than three stress terms.