Evaluation of Stress Intensity Factor using Displacement Correlation Techniques

The simulation of crack propagation relies on accurate computing of stress intensity factors (SIFs) at crack tips. Numerical methods are used to calculate the crack propagation path based on the computation of the crack incremental direction and stress intensity factors KIfKnfrom the finite element response.This paper evaluates a nodal displacement method used for prediction of stress intensity factors.The method evaluated is the displacement correlation technique (DCT).The DCT is used when the singular element is present at the crack tip, and it uses the differential displacements for the adjacent nodes across the crack to compute the stress intensity factors.The crack path and its stress intensity factors are calculated in a specialised finite element program, using small crack increments. At each crack propagation step,the mesh is automatically refined based on automatic adaptive strategy that takes into account the estimation of stress analysis in two-dimension elastoplastic fracture. Crack has been modelled to propagate through the inter-element in the mesh. The crack is free to propagates without predetermine path direction. Maximum principal normal stress criterion is used as the direction criterion.