Benchmark multi-layer simulations for residual stresses and deformation in small additively manufactured metal parts

Abstract

Scan pattern dependent (multi-track) residual stress buildup over multiple layers in the powder bed fusion process is governed by coupled thermo-mechanics. The high computational cost associated with these simulations has resulted in the general adoption of approximate computational methods. The numerical or thermo-mechanical accuracy of assumptions made in these computational methods is not fully characterized. If benchmark multi-track simulations for small size multi-layer parts are available, including temperatures, strain fields and deformation results, it will be possible to scientifically develop new approximation schemes or modify existing ones to improve their accuracy. Present work develops a suggestive benchmark using full multi-track thermomechanical simulations, with comparison to various approximate methods. The target configurations are simple prismatic geometries with 30 layers and up to 120 mm 3 volume, illustrating the influence of domain size on the approximate results. Anticipating the future challenges of measuring stresses and deformation in these small benchmark geometries, an experimental setup based on sheet metal forming principals is demonstrated numerically. The proposed setup will provide a methodology to experimentally validate these benchmarks.