Further Studies to Evaluate Crack Opening Areas for Through-Wall Cracks in the Vicinity of Welded Attachments

A paper was presented at the 2009 ASME PVP Conference on evaluating, by finite element techniques, crack opening area (COA) and stress intensity factor, K_I, values for through-wall cracks located in the region where an attachment is welded to a plate geometry. Both membrane and bend loads were considered. In addition, based on the stress profile in the un-cracked complex geometry over the region where the cracks would be introduced, COA and K_I values were evaluated for the same crack sizes located in a simple plate geometry. This enabled information to be established on the conservatism, or otherwise, of using simple plate solutions to evaluate COA and K_I for cracks in the complex geometry. The present paper reports on further studies that have been undertaken to investigate the effect on the previous COA and K_I results of considering (i) large displacement theory which may be important for combined membrane and bend loading, and (ii) contact elements in the finite element models since in the previous studies, the mesh was allowed to “overlap on itself” when crack closure was evident due to compressive stresses during bend loading.