Influence of Different Factors on Finite Element Simulation of Transient Heat Transfer Problem in Welding

In this paper two case studies on transient heat transfer problems are performed to examine the convergence of the numerics associated with such problems, including the assessment of the influence of mesh refinement, finite element (FE) type and time increment on the computed temperature results and convergence behaviour. In Case study 1 a simple cylindrical stainless steel shaft with constant thermal properties and an initial temperature of 600oC is cooled down in a room with a fixed temperature. The computed temperature values are compared with the theoretical solution. In Case study 2 the transient heat transfer associated with the weld process of a butt weld is studied. The weld process is modelled as a sequence of heating and cooling processes. In this case study temperature dependent material properties are used. Analyses are performed with the FE solvers ABAQUS and ANSYS to see, if both codes deliver similar results. It turned out that the time increment has the largest impact on the convergence behaviour and computed temperature results. The mesh density can improve the convergence of the analyses, if a not too large time increment is used, but has negligible impact on the computed temperature results. The FE type used has no impact on the computed results and there is no difference in the results of two FE solvers.