Residual stress prediction in selective laser melting: A critical review of simulation strategies

This review focuses on the analysis of numerical models aimed at predicting the residual stress-strain field produced by the selective laser melting process. Our first intent is to favor an intuitive understanding of the underlying physics and then to provide an overview of the available simulation strategies specifying their field of application. In fact, given the complexity and the multi-scale nature of the process, various tailored models are needed for the assessment and prediction of defects and manufacturing issues arising during the building phase. Regarding the estimation of residual stresses, the available models were reviewed and classified on the basis of the dimensional scale of the simulated phenomena. Meso-scale models perform the detailed simulation of the scanning process, but the high computational cost currently prevents their application on the whole build volume (the current limit on the scanning volume is approximately 100 mm3 with dynamic mesh coarsening techniques). Macro-scale models have been developed to overcome this limit by introducing deep simplifications of the thermo-structural problem. From our review, it appears that meso-scale modeling has reached a significant maturity, while a widely adopted strategy for macro-scale simulations has not emerged yet.