Comparison of Different Methods of Evaluation of Weight Functions for 2D Mixed-Mode Fracture Analysis,” Engineering Fracture Mechanics

Abstract-In this paper, two different techniques for mixed-mode type engineering fracture analysis, by using the weight-function method, are presented. These two methods are (a) the virtual crack extension technique (VCE), and (b) the equivalent domain integral method (EDI). For mixed-mode weight-function evaluation, a technique of using two reference load states, both of which cannot be either pure mode I or pure mode II, is combined with the above mentioned numerical schemes. The numerical results show that the weight functions calculated by these two methods coincide with each other well. With the proposed techniques, it is very straightforward to perform fracture analysis of isotropic, orthotropic and composite materials. 1. ~RODU~ION STRESS intensity factors K, and K,, are important parameters in solving fracture problem @ J. There are several numerical methods for evaluating the stress intensity factors. The hybrid finite element method[2-4], integral equation[5], and the alternating method[6] are some examples for such numerical schemes. In the practical application of fracture mechanics, the determination of weight functions is often more advantageous than the calculation of stress intensity factors alone: in life predictio