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 resi dual stresses is examined. The emphasis in this study is in accounting for crack surface contact. The importance of such problems is realize d in both crack detection and in the stress intensity factor calculati ons. The line spring model is used to iteratively determine the border of the closed portion of the crack and the stress intensity factors a long the open portion. It is demonstrated that the model is very versa tile for solving contact problems. Examples for both surface and inter nal cracks are given. It is shown that if crack contact is ignored, th e stress intensity factor may be significantly underestimated.