The Numerical Simulation of Crack Growth in Weld-Induced Residual Stress Fields

摘要

A marriage of elastic plastic fracture mechanics techniques with thermoplastic finite element analyses is developed to examine crack growth in the presence of weld-induced residual stresses. A hypothetical crack growth relation based on the crack tip opening displacement is used. Three problem areas are studied: stress corrosion cracking in a girth-welded pipe, fatigue crack growth under cyclic loading in a butt-welded plate, and dynamic crack propagation under impact loading in a butt-welded plate. Comparisons with computations carried out under conventional linear elastic assumptions are made. It is found that, in all three cases, neglect of the plastic deformation caused by the welding process appears to be anti-conservative. It is concluded that more realistic computations for crack growth in and around welds than are commonly used may be needed for realistic structural integrity assessments. (Author)