A Modified Inherent Strain Method for Fast Prediction of Residual Deformation in Additive Manufacturing of Metal Parts

Effective prediction of residual deformation is very important to guarantee the quality of metal parts produced by additive manufacturing (AM). However, analytical or numerical models for the AM process are complicated and time consuming thus far. The conventional inherent strain theory can predict residual distortion of the regular metal welding problem. Typically, it is not applicable to the complicated layer-by-layer laser-sintering depositing process. In this paper, a modified inherent strain method is presented to predict the residual deformation much more efficiently. Calculation of the modified inherent strain is based on small-scale thermomechanical simulation of the AM process. Next, the strain values are assigned to the heat-affected zone as material thermal property and a one-time static mechanical analysis is performed. Residual deformation obtained by the new method and the thermomechanical simulation indicates good accuracy and efficiency of the proposed method.