Thermomechanical modeling of additively manufactured structural parts - Different approaches on the macroscale

Abstract

Modeling the metal additive manufacturing process can be done on different length scales depending on the field of interest. However, due to the moving heat source and the narrow heat affected zone, a fine mesh and fine time resolution are required to analyze detailed information on various length scales. In this paper, the focus is on macro-scale temperature, deformation and residual stresses. The inherent strain method is applied layer by layer on the full part, to include the thermal contraction and inelastic strains generated by the moving heat source. The inherent strain components are mapped from the mesoscale simulations, where different boundary conditions can be used to resemble different regions from the macroscale. As an alternative to the inherent strain method and to include the thermal simulation on macroscale without simulating the moving heat source, a layer-by-layer approach is proposed and applied in the paper. The price to pay is the loss in detail of the thermal load. However, for the suggested layer-by-layer approach, the energy corresponds to the energy delivered from the laser. The proposed and implemented methods are applied to two examples and compared to measurements. Finally, large structural parts are simulated to evaluate the application on new trends in the automotive industry.