Embedded crack model: II. Combination with smear cracks

The paper investigates the behaviour of finite elements with embedded displ acement discontinuities that represent cracks. Examples of fracture simulat ions show that an incorrect separation of nodes due to a locally mispredict ed crack direction leads to a severe stress locking, which produces spuriou s secondary cracking. As a possible remedy the paper advocates a new concep t of a model with transition from a smeared to an embedded (discrete) crack . An additional improvement is achieved by reformulating the smeared part a s non-local. Various criteria for placing the discontinuity are compared, a nd the optimal technique is identified. Remarkable insensitivity of the res ulting model to mesh-induced directional bias is demonstrated. it is shown that the transition to an explicit description of a widely opening crack as a displacement discontinuity improves the behaviour of the combined model and remedies certain pathologies exhibited by regularized continuum models. Copyright (C) 2001 John Wiley & Sons, Ltd.