A novel coupling approach of smoothed particle hydrodynamic with discrete element method for simulating selective laser melting process

Selective laser melting (SLM) is an advanced additive manufacturing (AM) technique, which uses a high-energy laser beam to scan metal powders and substrates, melting and solidifying them layer by layer, ultimately forming metal parts. During the scanning process, the molten pool formed by the melting of the metal flows violently and creates a strong interaction with the metal powder surrounding the molten pool, which has a significant impact on the size, topography, and surface defects of the molten pool. In this paper, we develop a novel coupling method of smoothed particle hydrodynamic (SPH) with discrete element method (DEM) for simulating the SLM process, which makes full use of the SPH to model the melt pool flow and the DEM to model the motion of powder. A novel coupling algorithm is proposed to handle the interaction between DEM particle and SPH particle, in which a DEM particle will be discretized by multiple SPH powder particles to model local melting of powder and converting the DEM particle into SPH particles, and the heat transfer algorithm and coupling force algorithm between the DEM particle and SPH particle is developed. Serial numerical examples are studied to verify the correctness and effectiveness of the proposed SPH-DEM coupling method, and comparing with results with other sources and experiments, it can be shown that the proposed SPH-DEM coupling method is effective in simulating the selective laser melting process.