Simulation of laser welding using advanced particle methods

The process of laser welding is modelled using the meshless Lagrangian Smoothed Particle Hydrodynamics (SPH) method. Significant physical effects during the welding process like heat conduction, surface tension, and the occuring phase transitions melting, solidification, and evaporation are considered in the model. By coupling an SPH code with a ray tracer that tracks the propagation of independent light rays in the capillary and calculates the locally absorbed intensity by means of geometrical optics, the laser-material interaction is represented in detail, even for complex capillary geometries. Therefore, both heat conduction and deep penetration laser welding can be simulated using this co-simulation approach. The model is able to predict the temperature distribution during the welding process and the dimensions of the resulting weld seam. Furthermore, the vaporisation threshold and deep penetration threshold can be estimated. The numerical results are validated by comparing the obtained threshold values with experimental data and an analytical approximation during seam welding of aluminum. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)