Topology optimization (TO) is commonly used to minimize the weight of a structural component subject to a constraint on the maximum equivalent stress. In TO for additive manufacturing (AM), constraints on the build direction as well as the overhang angle are also included in the optimization. However, current design framework generally doesn’t include the residual stresses and distortions that result from the AM process directly into the TO. In this work, it is shown that this limitation can result in components that may fail during the Selective Laser Melting (SLM) due to high stresses and distortion that were not accounted for in the TO. For the studied demonstrative bracket design from Ti-6Al-4V, it is shown that the spatial stress distribution, including both the location and magnitude of the maximum stress, is strongly altered after SLM compared to the stresses used in the TO, even after heat treatment. This work highlights the importance of integrating AM process simulation with residual stress and distortion prediction directly in the TO, which is currently a difficult and computationally inefficient task.
Part of proceedings: ISBN 978-1-64368-268-6
QC 20220506