On J Integral as Fracture Parameter in Heterogeneous Welded Joints

摘要

The J integral parameter and the feasibility of its application in welded joints with different weldmatchings in yield strength (overmatching weld and undermatching weld), different material constitutive laws (Material with a Ludes yield plateau and power hardening) and under different fracture types (ligament yielding fracture and general yielding fracture) are investigated. The condition of J integral path independence has been studied based upon finite deformation elastic-plastic finite element analyss by using ADINA code on welded joints mentioned above. It was shown that J integral is path dependent for the cases studied in this paper. Experiments were carried out to study the availability of J integral as a plastic singularity parameter at the tip of the notch in welded joints. The results showed that J dominance in most cases studied is not validated in v and u displacement fields. It can therefore be concluded that the J-integral as a controlling parameter which is used to estimate the safety of welded strutures is not always valid.