Modeling the thermomechanical processes and residual stresses in additive manufacturing of metallic components

Abstract

In additive manufacturing of metallic components and fusion welding, undesirable deformations and residual stresses are common drawbacks, which directly influence the performance and functionality of the manufactured components. In this work, a thermomechanical continuum model is developed by using the phase‐field method to track the evolution of the melting/remelting‐solidification occurring due to the incident of localized heat input sources, e.g, by means of a laser heat source. The result of the thermal analysis is then employed for the mechanical analysis to predict the residual stresses. In the thermal and mechanical analysis, the thermomechanical properties are considered to evolve with the phase‐field variable. In addition, a scalar‐valued history variable is introduced to distinguish between consolidated and loose powder materials. This enables single‐track additive manufacturing simulations with a possible extension to multi‐layer and multi‐track simulations. To verify and validate the modeling approach, the coupled system of equations is implemented in the open‐source FEniCS project and a numerical example for additive manufacturing is solved and compared qualitatively and quantitatively with reference results from the literature.