Use of the reference stress concept to assess the effect of crack growth increment size on the accuracy of creep crack grow predictions

Abstract

An approximate method, based on the reference stress concept, for carrying out ‘moving-crack’ calculations, under creep conditions, is presented. Creep crack growth is assumed to be related to the C∗ parameter. The predictions obtained correlate well with detailed, ‘moving-crack’, finite element calculations. Preliminary calculations, to assess the adequacy of finite element meshes and the effect of variations in material properties on the accuracy of predictions, can be carried out quickly and relatively cheaply. The usefulness of the technique is illustrated by using it to show the effect of the magnitude of the crack growth increment assumed and of the value of critical crack tip opening displacement (the initiation parameter assumed) used.