The Woodruff School

SUMMARY

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’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 “AM-friendly”, for they represent the true optimal geometry or mechanical performance of the fabricated part. In the aspect of AM: The improved manufacturability of topology optimized designs eases transition from optimal design to final part fabrication, and application of AM in printing critical components is made more reliable.

SUBJECT:	Ph.D. Proposal Presentation

BY:	Yeming Xian

TIME:	Wednesday, November 25, 2020, 3:00 p.m.

PLACE:	https://zoom.us/j/4941584878, -

TITLE:	Extensions of Topology Optimization for Additive Manufacturing

COMMITTEE:	Dr. David Rosen, Co-Chair (Mechanical Engineering) Dr. Glaucio Paulino, Co-Chair (Civil and Environmental Engineering) Dr. Yan Wang (Mechanical Engineering) Dr. Christopher Saldana (Mechanical Engineering) Dr. Oliver Giraldo-Londoño (Civil and Environmental Engineering)

SUMMARY 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’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 “AM-friendly”, for they represent the true optimal geometry or mechanical performance of the fabricated part. In the aspect of AM: The improved manufacturability of topology optimized designs eases transition from optimal design to final part fabrication, and application of AM in printing critical components is made more reliable.