Discussion Forum

Dear Comsol community,

I´m struggling a lot with my model, as it keeps failing due to convergence problems. My goal is to calculate different reaction forces on clamping devices during laser beam welding of an overlap joint. Please find attached my current model for a better understanding. For this purpose two partially overlapping metal plates were modelled as two blocks in Comsol with customized material properties (declared as temperature dependent variables in German language). The two plates are clamped in z direction in the middle. The laser beam meets the Block directly on the joint. The Laser is simulated as a moving Gaussian heat source on the surface. Since the laser meets two surfaces, the Gaussian distribution was divided in two and each half was projected on the corresponding surface. Some Heat transfer effects where considered.

As a first step I´d like to calculate the reaction forces on the right and on the left side, where each metal plate is clamped. For this purpose I decided to use a prescribed displacement (=0) on both sides. Unfortunately my third study, where it´s supposed to calculate the mechanical response on the thermal changes, keeps failing due to a convergence error. Strangely enough it always fails during the cooling period several seconds after the welding process itself has finished. What I´ve already tried is to change the material to a standard steel and to make the mesh even finer. Does anyone have a hint how to solve this?

I would be very thankful for some advice!!

Best regards, Jonas