A study of some issues in stable tearing crack growth simulations

This paper investigates several issues in stable crack growth simulations relevant to the application of a particular crack-growth criterion based on the crack-tip opening displacement (CTOD). Specifically, the effects of finite element size, CTOD location, and large rotation on the performance of the CTOD criterion are examined. Finite element simulations of actual crack growth tests on Arcan specimens are carried out under plane stress and Mode-I conditions using a custom code ZIP2DL. With regard to finite element predictions for the load-crack-extension curve, the results of the simulations suggest the following. First, when elements are small enough along the crack growth path to produce converged crack-tip opening displacement (not necessarily converged crack-tip stresses and strains), the size of the elements has negligible effect, Second, the fixed distance between the CTOD location and the current crack-tip should be chosen so that it is consistent with the choice of the element size along the crack path and of the critical CTOD value. Third, the effect of large specimen rotation can be dealt with by performing both the CTOD calibration and its application under small-deformation conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.