Multiphysics modeling of metal based additive manufacturing processes with focus on thermomechanical conditions

Metal additive manufacturing (MAM) has been experiencing huge growth thanks to the increase in production performance as well as our fundamental knowledge of the process. Production defects are, however, slowing down the implementation of components produced with this technology. Such defects, like porosities and distortions, are mainly related to the temperature development (and the subsequent residual stresses) within the part during printing. Prediction of temperatures and stresses during production is still challenging due to the complexity of the process, requiring experimental tests as well as numerical simulations to achieve the desired components. In this work, the main modeling techniques of MAM from micro- to part-scale are described, with focus on thermomechanical modeling. Some reduced order methods have been developed in this field and among these, Flash Heating (FH) and Sequential Flash Heating (SFH) have shown the possibility of obtaining reliable numerical results within short simulation times, thanks to the lumping of the part into meta-layers. Four case studies involving both LPBF and DED are presented and validated against proper experiments. Based on this, it is envisioned that FH and SFH methods can be part of a multi-scale, multi-physics modeling framework, in which models at different length-scales are coupled.