Thermo-mechanical modelling of additive manufacturing: activation of non-constructed domain and effect of kinematic hardening

Abstract

A thermo-mechanical finite element model is developed for additive manufacturing by directed energy deposition (DED). The simulation is conducted at the part scale by modelling the progressive deposition in the way of the fraction of the layer. To incrementally resolve the displacement, strain, and stress fields, a theoretical formulation for the kinematic positioning is proposed to minimize the distortion of the non-constructed fraction by considering current displacement and strain in the constructed part, which can resolve the discontinuous problem at the interface for a patch of material depositions. Moreover, it is found that the kinematic hardening couldn’t be ignored for the back-and-forth deposition mode of the DED process. The application for a turbine blade with a strong curvature is adopted, and the distributions of distortion and stress during mid-construction and final construction are studied.