Finite element analysis of welding processes in consideration of transformation plasticity

Abstract

Arc-welded structures are widely used in ship constructions, heavy industries, nuclear power plants etc. and the structural analysis of these arc-welded structures has been a key concern in the light of the structural integrity and quality control. Material elements undergo a complex thermomechanical process combined with metallurgical phase transformation in welding, and this results in a substantial amount of residual deformation and stress in the welded structure. Therefore it is essential to analyze the welding process for accurate evaluation of structural integrity of welded structure. However, the process is a complex nonlinear process involving phase transformation, heat transfer, and time dependent finite strain thermoelastic plastic deformations, and so it requires an enormous amount of computing time to analyze the process, particularly for a three dimensional structure. To establish a fast and effective solution procedure, in this study we consider an efficient numerical implementation of finite element formulation of welding process, and explore the application of adaptive meshing technique and parallel computation. We choose Leblond and Devaux[19] for the kinetic equations of phase transformation and Leblond et al[23, 24] for the constitutive equations in consideration of transformation plasticity for the formulation of welding processes. The kinetic equations and the constitutive model have drawn a great deal of attention in the welding community and adopted in the commercial code SYSWELD. We proposed an efficient formulation and implementation for the finite element analysis of welding processes including metallurgical phase transformation employed by the hyper-thermo-elasto-plastic formulation and multiplicative decomposition of deformation gradients. Furthermore, the closed form consistent tangent moduli for the formulation are derived and we demonstrate the accuracy and the efficiency of the present implementation by comparison to SYSWELD thro...