Effect of location and dimensions of welded cover plate on stress intensity factors of cracked plates

Three dimensional finite element model was utilized to determine mode I stress intensity factor through the front of a single edge crack in main plate with welded cover plate. The numerical results showed that the ratio of the crack length to the position of the welded cover plate end is a crucial parameter for describing the efficiency of the cover plate location. When the crack tip just reached the cover plate end, the cover plate efficiency is only dependent on the cover plate dimensions regardless the location of the cover plate or the crack length. In the case of crack front not reached the cover plate end, the location of cover plate near the edge of the main plate, i.e., near the crack mouth, is less efficient than that faraway. However, the opposite trend was found for cracks pass beneath the cover plate.