In the present work, a comprehensive framework for finite element-based computational modelling of Directed Energy Deposition (DED) process is presented. The proposed approach can be fully automated and implemented on a complex real-life part geometry to accurately predict a thermo-mechanical response during the full-scale deposition process. The discrete material deposition modelling in Finite Element Analysis (FEA) leads to artificial increases in temperature gradients in the melt pool domain. A new method is therefore proposed that aims to mitigate these gradients. Additionally, an easy-to-implement free-surface detection algorithm to accurately prescribe the evolving heat transfer boundary conditions is presented. A three-dimensional sequentially coupled thermo-mechanical model of the process is then validated against experimental data obtained in a deposition case study. The simulation results show good agreement with the in-situ temperature measurements taken during the actual deposition. In addition, result analysis showed that the largest tensile residual stresses form in the hoop and axial direction on the outer domain of the thin-wall cylindrical part near the base plate while the inward material is compressed.

Predstavljen je algoritem za dolocitev najprimernejse temperaturno odvisne poti dodajanja materiala, oz. t. i. 3D tiska, na podlagi metode koncnih elementov (MKE). Izracunana pot, v primerjavi s konvencionalnim enosmernim ali dvosmernim tiskom, rezultira v enakomernejsem temperaturnem polju po obmocju izdelka, nižjih temperaturnih gradientih in posledicno manjsih deformacijah ter zaostalih napetostih v koncnem izdelku.

Wire-arc welding-based additive manufacturing (WAAM) is a 3D printing technology for production of near-net-shape parts with complex geometry. This printing technology enables to build up a required shape layer by layer with a deposition of a consumable welding wire, where the welding arc is a source of heat. Welding is usually performed by CNC-controlled robotic manipulator, which provides a controlled location of material layer adding. Because the process itself involves thermo-mechanically complex phenomena, Finite Element-based virtual models are commonly employed to optimize the process parameters. This paper presents advanced computational modelling of the WAAM of a tube. A thermo-mechanical numerical model of the process is calibrated against experimental data, measured as temperature variation at the acquisition point. The virtual modelling starts with a preparation of the tube geometry in CAD software, where the geometry of the single-layer cross-section is assumed. The geometry is then exported to a G-code format data file and used to control robotic manipulator motion. On the other side, the code serves as an input to in-house developed code for automatic FEs activation in the simulation of the material layer-adding process. The time of activation of the finite elements (FEs) is directly related to the material deposition rate. The activation of the FEs is followed by a heat source, modeled with a double ellipsoidal power density distribution. The thermo-mechanical problem was solved as uncoupled to speed-up computation.