THE EVOLUTION OF THERMAL DISTORTION AND STRESSES AT MACRO SCALE FOR METAL ADDITIVELY MANUFACTURED PART

The Selective Laser Melting (SLM) involves the melting of the metal powder
resulting in melt-pool. When this very melt-pool solidifies, the solidified metal
undergoes cooling and reheating in the presence of air and multiple laser
passes for continuous material consolidation. In result of such thermal cycles,
manufactured part develops the permanent thermal deformation and residual
stresses[1]. The current study, involves the evaluation of part deformation and
development of residual stresses at macro scale. The multi-physics solution is
performed by coupling of transient thermal heat equation with structural
solver equipped with the elastoplastic material model. The FeniCS[2] Finite
Element Modelling platform is utilized in the development. To mimic the
consolidation of material, the elements are activated as per the pattern of
metal consolidation under the influence of G-code. The results are gathered to
track down the evolution of plastic strain and residual stresses throughout the
course of part manufacturing. The significance of temperature dependent
material properties is also focused. The generation of permanent deformation
and the thermal stress is studied among the cases of constant material
properties and the material properties as a function of temperature.
Moreover, the the upscaling of material deposition and the parallelization of
the simulation platform is currently under focus for enhanced computational
efficiency of the developed algorithm.