Phenomenological evaluation of laser welding processes with a combined use of higher-accuracy experiments and computational science methodologies, 4; Numerical simulation of the welding processes with a multi-dimensional multi-physics analysis code SPLICE

Yamashita, Susumu   ; Yamada, Tomonori; Kunugi, Tomoaki*; Muramatsu, Toshiharu

In a residual stress simulation for a welded portion, it has been often carried out thermo-elastic-plastic analysis based on an FEM approach. In the analysis, thermal stress which mainly affects a residual stress is obtained using only a thermal history derived by heat conduction analysis without the thermohydraulics in the molten pool. However, a thermal history might be greatly affected by the convection in a molten pool. Therefore, in order to precisely predict and control a residual stress, the investigation of the thermohydraulic phenomena in the molten pool is quite important. Thus, we used a multi-purpose multi-dimensional code named SPLICE including FSI model as a solid-fluid interaction based on the one-fluid model which is often used in numerical simulation for multiphase flows and is based on a finite difference method, for molten pool analyses. As a result, the temperature distribution which influences residual stresses in the welded portion is greatly affected by characteristics of the convection in the molten pool. Therefore, it is concluded that the thermohydraulic phenomena in the molten pool, it has been not taken into account in conventional residual stress simulations, will be not negligible and important factor in a laser welding process.