Decomposed crack closure integrals for estimation of SIF variations

The Modified Crack Closure Integral is a popular, convenient and very effec tive post-processing tool for extracting the stress intensity factors (SIF) from finite element analysis (FEA) of cracked structures in individual or mixed-mode situations. In 3D, the current practice is to estimate the strai n energy release rate over the brick element and mark the corresponding SIF to the center of the brick edge representing the crack front. This suppres ses the information regarding SIF variations within the element. This paper presents a novel concept of decomposing the nodal forces, nodal displaceme nts and the strain energy release rate into their constituent parts for ext racting the SIF variations consistent with the element shape functions. Dec omposed Crack Closure Integral (DCCI) has been formulated for linearly vary ing SIF in an 8-noded brick and parabolically varying SIF in a 20-noded bri ck element. (C) 1999 Elsevier Science Ltd. All rights reserved.