An experimental and numerical case study of thermal and mechanical consequences induced by laser welding process

In this study, an experimental benchmark with different welding conditions is developed. In-situ diagnostics tools (high-speed camera, thermocouple) and ex-situ diagnostics devices (high-resolution digital microscope, measuring arm, X-Ray diffraction device) are exploited to measure various physical quantities. These measurements set up a complete database of laser welding benchmarks, which can establish a relationship between welding parameters and thermo-mechanical consequences. Meanwhile, the finite element method is used to investigate such a process and understand the multi-physics coupling problems behind the process. Numerical and experimental comparisons are performed in two steps. Firstly, the molten pool morphology and temperature evolution are employed to calibrate the 3D volumetric heat source. Secondly, a thermo-mechanical coupling is carried out by imposing the thermal strain calculated from the calibrated thermal model. Thermo-elastoplastic models with isotropic and kinematic hardening are used to compute the distortion and residual stresses. Mechanical results (distortions and residual stresses) of numerical models are compared with those of the benchmark. Overall, a good correlation is found. Thus, this paper provides a full experimental case study and numerical solution for laser welding process, which allows researchers to validate their numerical models and also gives some insights for modeling welding processes.