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Efficient design optimization of variable-density cellular structures for additive manufacturing: theory and experimental validation

Lin Cheng (Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA)
Pu Zhang (Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA)
Emre Biyikli (Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA)
Jiaxi Bai (Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA)
Joshua Robbins (Department of Multiscale Science, Sandia National Laboratories, Albuquerque, New Mexico, USA)
Albert To (Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 20 June 2017

Abstract

Purpose

The purpose of the paper is to propose a homogenization-based topology optimization method to optimize the design of variable-density cellular structure, in order to achieve lightweight design and overcome some of the manufacturability issues in additive manufacturing.

Design/methodology/approach

First, homogenization is performed to capture the effective mechanical properties of cellular structures through the scaling law as a function their relative density. Second, the scaling law is used directly in the topology optimization algorithm to compute the optimal density distribution for the part being optimized. Third, a new technique is presented to reconstruct the computer-aided design (CAD) model of the optimal variable-density cellular structure. The proposed method is validated by comparing the results obtained through homogenized model, full-scale simulation and experimentally testing the optimized parts after being additive manufactured.

Findings

The test examples demonstrate that the homogenization-based method is efficient, accurate and is able to produce manufacturable designs.

Originality/value

The optimized designs in our examples also show significant increase in stiffness and strength when compared to the original designs with identical overall weight.

Keywords

Acknowledgements

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. The authors from University of Pittsburgh gratefully acknowledge financial support from American Makes (National Additive Manufacturing Innovation Institute). This material is based on research sponsored by Air Force Research Laboratory under agreement number FA8650-12-2-7230. The US Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the US Government.

Citation

Cheng, L., Zhang, P., Biyikli, E., Bai, J., Robbins, J. and To, A. (2017), "Efficient design optimization of variable-density cellular structures for additive manufacturing: theory and experimental validation", Rapid Prototyping Journal, Vol. 23 No. 4, pp. 660-677. https://doi.org/10.1108/RPJ-04-2016-0069

Publisher

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Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited