Local and global energy densities associated with welding residual stresses of cracked structures

Abstract

The residual stresses associated with fusion welding processes have recently become a popular issue considering the reliable design of structural components. In a welding problem, it is quite common that fracture is observed to initiate either directly from the welds or from fatigue cracks that develop in the weld's heat affected zone (HAZ). A recent study has investigated the effects of subsequent dynamic loading with stationary crack fronts, which assumes load being applied to the structure following the welding process. To analyze these types of problems, a computational procedure based on finite element methodology is developed to integrate the welding residual stresses with subsequent dynamic fracture behavior. The welding analysis is performed with a welding simulation program (SYSWELD). The inclusion of residual stresses and the determination of classical fracture parameters are handled with a specialized finite element program, called FRAC3D. The calculation of energy densities that are recently used in the analysis of cracked structures was shown to be an effective method for the solution of fracture problems. In this paper, a new methodology that is developed to determine local and global energy densities for the simulation of dynamic fracture behavior with initial welding residual stresses is presented.