Numerical simulation of full-scale thermal-force coupling for LPBFbased on thermoelastic-plastic intrinsic model

Laser powder bed fusion (LPBF) is an important branch of metal additive manufacturing technology, offering advantages such as customization and automation. However, during the layer-by-layer fabrication process, residual stresses continuously accumulate, which can readily induce issues like deformation, fracture, and fatigue, thereby limiting its wider application. To predict the displacement and residual stress in metal additively manufactured components, this study employs the open-source finite element solver JAX-FEM to conduct full-scale thermo-mechanical coupled numerical simulations of LPBF based on a thermo-elastoplastic constitutive model. Equivalent laser power, equivalent laser radius, and scanning speed were determined according to the principle of energy conservation to simplify the computational model and reduce calculation time. The process of separating the component from the substrate was simulated, and the effects of stress release were predicted by adjusting the stress state at the component's bottom surface. The influences of scanning strategy and scanning speed on the thermo-mechanical coupled behavior during LPBF were analyzed. Comparative results reveal that employing a horizontal zigzag scanning strategy, compared to a vertical scanning strategy, resulted in a 24.0% reduction in maximum displacement and a 13.6% reduction in maximum residual stress. Increasing the scanning speed from 0.8 m/s to 2.0 m/s led to an 8.9% reduction in maximum displacement and a 13.1% reduction in maximum residual stress. This study offers scientific insights for regulating residual stress and deformation in LPBF.