A novel mesoscale transitional approach for capturing localized effects in laser powder bed fusion simulations

This paper introduces a new mesoscale approach for considering local fluctuations of powder bed characteristics in laser powder bed fusion (PBF-LB/M) simulation, bridging the gap between computational fluid dynamics (CFD) and homogenized mesoscale models. Gusarov and Sih's models for laser heat input and powder bed thermal conductivity were applied to local powder bed elements (PBE) to capture characteristics in the powder bed. Discrete element method (DEM) simulations of the recoating process generated a representative powder bed and determined local porosity values. These values informed local optical thicknesses and thermal conductivities, providing insights into heat transfer in PBF-LB/M. Single-track test simulations showed melt pool sizes matched best with homogenized parameters. The PBE-based approach resulted in smaller melt pools and revealed asymmetries in heat distribution due to varying powder bed characteristics, highlighting the need for accurate powder bed modeling. This mesoscale approach offers an efficient, time-saving alternative to CFD simulations.