CRACK SURFACE-CONTACT OF SURFACE AND INTERNAL CRACKS IN A PLATE WITH RESIDUAL-STRESSES

The problem of a mode I surface or internal crack in a plate with residual stresses is examined. The emphasis in this study is in accounting for crack surface contact. The importance of such problems is realized in both crack detection and in the stress intensity factor calculations. The line spring model is used to iteratively determine the border of the closed portion of the crack and the stress intensity factors along the open portion. It is demonstrated that the model is very versatile for solving contact problems. Examples for both surface and internal cracks are given. It is shown that if crack contact is ignored, the stress intensity factor may be significantly underestimated.