EFFECT OF MECHANICAL HETEROGENEITY ON THE BEHAVIOR OF A CRACK IN THE WELD HEAT-AFFECTED ZONE - A NUMERICAL-ANALYSIS

Both mechanical heterogeneity and crack position effects on the stress and strain fields at the crack tip of overmatching and undermatching weld metal joints are investigated. Analyses under sustained plane strain yielding conditions of a notch ''near to'' and ''at'' the interface between two elastic-plastic materials of a double edge notch tensile specimen have been carried out by finite element method. The results are used to study the implications of the difference in plastic properties on the behavior of a crack in the weld heated affected zone (HAZ), as well as to discuss its more critical position, regarding the fusion line, for the evaluation of HAZ weld fracture toughness. The contribution to the notch tip opening displacement of each material in heterogeneous cases, and the notch tip sliding displacement, have been related to remote load for the different cases considered.