Finite element simulation of multi-pass welding process with rezoning technique

Abstract

Finite element simulation of welding process has been wildly employed in engineering where welding deformation and residual stress are considered. One big problem during simulation is the severe demands of capacity of hard disk and computation time, especially for large structures with long weld length or multi-pass welding. To minimize the number of unknowns in finite element model, a rezoning technique is developed to simulate the multi-pass welding process. The local nonlinear zone around the current pass is modeled with a dense finite element mesh, while the region of other passes and nearby is modeled with a coarser mesh. Then the model is redefined layer by layer to represent the filling of the welding pass and the motion of the weld arc. The rezoning procedure is implemented using a reverse mapping algorithm with Newton method to solve the high order simultaneous equations. Three-dimensional finite element simulations with and without rezoning technique are performed to obtain transient temperature, welding deformation and residual stress. By comparing the results of the model, computational efficiency and accuracy of the proposed method is confirmed.