Numerical simulation of laser full penetration welding

A three dimensional finite element model has been developed to dynamically simulate the laser full penetration welding process. The parametric design capabilities of the finite element code ANSYS (revision 5.4) were employed for this purpose. The model calculates the transient temperature profile and the dimensions of the fusion zone during the welding process. The heat source was parameterized by the combination of a circular disk source with a Gaussian distribution of thermal flux with center on the top surface and a line source through the thickness of workpiece. The strength of the line source was calculated as a function of Peclet number and conductivity with the assumption of a conical profile of the keyhole. Various values of conductivity were examined for different welding speeds, to obtain the best agreement between the model and experiments. The results suggest that for different welding speeds, an effective conductivity for material must be used to predict the weld cross section. They also show that the weld shape is a strong function of Peclet number and conductivity of material. For this reason, it is essential to incorporate an accurate description of heat source.