UNIVERSAL CRACK CLOSURE INTEGRAL FOR SIF ESTIMATION

Numerical analysis of cracked structures often involves numerical esti mation of stress intensity factors (SIFs) at a crack tip/front. A newl y developed formulation called universal crack closure integral (UCCI) for the evaluation of potential energy release rates (PERRs) and the corresponding SIFs is presented in this paper. Unlike the existing ele ment dedicated forms of crack closure integrals (MCCI, VCCI) with appl ication limited to finite element analysis, this new numerical SIF/PER R estimation technique is independent of the basic stress analysis pro cedure, making it universally applicable. The second merit of this pro cedure is that it avoids the generally error-producing zones close to the crack tip/front singularity. The UCCI procedure, based on Irwin's original CCI, is formulated and explored using a simple 2D problem of a straight crack in an infinite sheet. It is then applied to some thre e-dimensional crack geometries with the stresses and displacements obt ained from a boundary element program. (C) 1998 Elsevier Science Ltd. All rights reserved.