THE CRACK OPENING AREA WHEN THERE IS LIMITED PLASTICITY

The paper is concerned with the accuracy of the effective elastic crac k procedure as it is applied to determining the crack opening when the re is limited plasticity, in the context of formulating a leak-before- break case for a component in a pressurized system. In strict terms, t he procedure is appropriate with regard to the stress and displacement fields at large distances from a crack tip. However, the crack openin g area is associated with the displacement of the crack faces at posit ions which are in fact close to a crack tip. This means that one shoul d question the use of the effective elastic crack procedure, as it is applied to crack opening area calculations. The present paper focusses on this issue, and by analysing a specific simple model, in fact show s that the procedure gives very accurate crack opening area prediction s up to high applied loading levels. On this reckoning, it would seem that the procedure can indeed be used with confidence in leak-before-b reak considerations. (C) 1998 Published by Elsevier Science Limited. A ll rights reserved.