A novel heat source model for welding and additive manufacturing: The traveling steady pool approach

Numerical simulation is essential in solving complex problems in welding and additive manufacturing (AM). However, conventional finite element analysis (FEA) models require repeated parameter tuning due to their inability to capture fluid behavior, while computational fluid dynamics (CFD) is often impractical for industrial applications. To address this, a Traveling Steady Pool (TSP) model was developed based on the observation that the molten pool stabilizes after a critical time. The steady pool geometry was extracted from CFD results, segmented into longitudinal sections, fitted with polynomial functions, and interpolated to construct a three-dimensional profile. This geometry was applied in FEA as a moving Dirichlet boundary at the melting temperature. The TSP model was validated against conventional heat source models and experimental data, including thermal images and bead cross-sections. Thermo-elasto-plastic simulations under various inclination angles further confirmed its predictive capability in deformation analysis. The model also provided physical insights into key phenomena, such as the enlarged CGHAZ at 45° and minimal deformation at 30°, based on the heat transfer characteristics of the molten pool geometry.