Experimental analysis and numerical simulation of Laser welding of thin austenitic stainless-steel sheets using two models: Bilinear isotropic strain hardening model and Johnson-Cook model

The objective of this study concerns simulation of Laser welding process, in a context of thin austenitic steel structures assembly. Experiments and numerical simulations have been performed in order to predict, in a robust way, distortions induced by the Laser welding. A comparison between experiments and simulations is performed, considering thermal and mechanical approaches. The experimental part of this work was based on instrumented tests. The in-situ measurements were carried out on sheets of 1 mm thickness. Macrographic observations in transverse section of the weld seam were performed in order to identify an equivalent heat source for butt welding configuration with filler metal. The identified heat source was then implemented into a thermo-mechanical model taking into account thermal, elastic and plastic strains. For this, two different behavior laws were tested for the computations, namely bilinear isotropic strain hardening model, and Johnson-Cook model (neglecting the strain rate effect).