This research aims to connect topology optimization (TopOpt) and additive manufacturing (AM), specifically, to improve additive manufacturability of the designs resulting from topology optimization, from two perspectives: geometry and performance. A topology optimized design fabricated by AM may not meet the optimal geometry or mechanical performance as held by the topology optimization result, due to AM process characteristics and limitations. We intend to address a few major aspects of this problem. Several topology optimization methods and frameworks will be investigated and used in this research. The following research questions will be answered.
Research question 1. How to adapt selected TopOpt method(s) such that geometry of the topology optimized design and that of the additively manufactured part are consistent with each other? This research question is divided into two topics. First, usage of support structure is minimized by adding overhang-related constraints in a TopOpt method. Second, we propose to eliminate enclosed voids from topology optimized design through additional constraints to another TopOpt formulation, to ensure accessibility of support structure during post-fabrication machining.
Research question 2. How to incorporate realistic AM-produced mechanical properties into selected TopOpt method(s)? For this research question we intend to use, in topology optimization, the realistic microstructure and material properties recorded in the literature of AM fabricated metal and alloy components, taking into account the anisotropy of properties and heterogeneities in local geometry. To that end, we plan to investigate the effect of local temperature history on structure{\textquoteright}s mechanical properties, and build the method on top of a multi-material TopOpt formulation in which sufficiently general volume constraints can be specified.
We want to demonstrate that topology optimization can be a design tool for additive manufacturing. This research, if successful, brings benefit to both fields. In the aspect of TopOpt: Topology optimized designs are made more meaningful and {\textquotedblleft}AM-friendly{\textquotedblright}, for they represent the true optimal geometry or mechanical performance of the fabricated part, after effects of AM process characteristics and limitations are considered in TopOpt, for example, inaccessibility of support structure at enclosed voids, and the need for support structure at overhanging geometry. This shows TopOpt can generate better designs in the design for additive manufacturing (DfAM) process. In the aspect of AM: The improved manufacturability of topology optimized designs eases transition from optimal design to final part fabrication. Application of AM in printing critical components is made more reliable, as mechanical properties of the as-printed part are more accurately estimated during TopOpt using realistic material properties. This research can be applied to fields in which it is beneficial to use DfAM for making reliable products at lower costs, such as in the aerospace and automotive fields.
}, year = {2024}, journal = {George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology}, publisher = {Georgia Institute of Technology}, url = {https://hdl.handle.net/1853/81482}, }