Simulations of directed energy deposition additive manufacturing process by smoothed particle hydrodynamics methods

This paper presents a novel application of a three-dimensional smoothed particle hydrodynamics model to simulate directed energy deposition (DED) additive manufacturing processes. A proposed workflow comprises a random powder generator to introduce individual powder particles into the SPH core simulation. The DED workflow simulation is successfully demonstrated for two real DED setups with significantly difference of individual powder/melt-pool size ratios and different materials. The simulation results are in good agreement with experimental data in terms of geometrical dimensions of deposited material and melt-pool surface temperature. Detail analyses on the results revealed transient internal characteristics of the melt-pool which otherwise nearly impossible to be observed from experimental data. These include the concave shape of the melt-pool surface, bifurcations and circulations of metal liquid flow, and spatial–temporal temperature distributions in the melt-pool which also vary with respect to scan parameters. These findings could provide better understanding on the DED processes that are difficult to measure and help achieve better quality of the printed products.