A Smoothed Particle Hydrodynamics Model for the Simulation of Laser Fusion Additive Manufacturing Processes

Additive Manufacturing (AM), aka 3D-Printing, is a broad class of rapidly emerging manufacturing technologies that build-up parts layer-by-layer through the addition of raw materials, under the guidance of a digital model. They are set to revolutionize the manufacturing world by allowing for rapid production of net-shape, customizable, ready-to-use parts in a variety of novel materials and designs. The development of numerical methods suited to the simulation of AM processes is of prime importance to industry and academia.In this work, the Smoothed Particle Hydrodynamics (SPH) method, a Lagrangian mesh-free numerical scheme, is adapted for the first time to resolve thermal-mechanical-material fields in a range of Laser Fusion Additive Manufacturing processes. The method is capable of simulating large-deformation, free-surface melting, flow, and re-solidification of metallic materials with complex physics and material geometries. A novel SPH formulation for modeling isothermally-incompressible fluids, which allows for the accurate simulation of thermally driven liquid metal expansion/contraction, is presented and verified. Fundamental validation of the methodology is performed via comparison with real world, spot laser welding experiments. The methodology is then used to investigate the the specific Additive Manufacturing Process of the Selective Laser Melting of Metallic, micro-scale Particle Beds. The physics of a track deposition process is explored through numerical experiments and the influence of processing parameters on the finished laser weld track quality is investigated. The SPH method is found to be a viable and promising numerical tool for simulating laser fusion driven Additive Manufacturing processes