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Title: Optimal design of fiber reinforced composite structures and their direct ink write fabrication

Abstract

The majority of the current structural optimization software does not accommodate manufacturing constraints. Therefore, substantial modifications are imposed upon optimized designs to make them manufacturable and hence nonoptimal. We propose to optimize the design of composite structures that are amenable to Additive Manufacturing (AM). The printing process chosen in our study is based on Direct Ink Writing (DIW) in which short carbon fibers in a thermoset resin are extruded through a moving nozzle to build up a structure. Since the fibers are primarily aligned in the flow direction of the extrudate, the DIW printing trajectory influences the material properties of the composite structure. To accommodate this, the extrudate trajectory follows the contours of parameterized level-set functions. The parametrization allows us to prescribe the material properties and impose many DIW manufacturing constraints such as no-overlap, no-sag, minimum radius of curvature and continuity of the toolpaths. Ultimately, we obtain optimal manufacturable toolpaths that start and finish at a boundary. To minimize the fabrication time, we formulate the linking sequence of the toolpaths as a traveling salesman problem which we solve to obtain the shortest continuous toolpath per layer. Several examples illustrate the optimization procedure. Validation is also performed.

Authors:
ORCiD logo [1];  [2];  [2];  [3]
  1. Univ. of Illinois at Urbana-Champaign, IL (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Illinois at Urbana-Champaign, IL (United States) ; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1598959
Report Number(s):
LLNL-JRNL-753091
Journal ID: ISSN 0045-7825; 939387
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Computer Methods in Applied Mechanics and Engineering
Additional Journal Information:
Journal Volume: 353; Journal Issue: C; Journal ID: ISSN 0045-7825
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Toolpath optimization; Additive manufacturing; Manufacturing constraints; Structural composites; Traveling salesman problem

Citation Formats

Fernandez, Felipe, Compel, W. Scott, Lewicki, James P., and Tortorelli, Daniel A. Optimal design of fiber reinforced composite structures and their direct ink write fabrication. United States: N. p., 2019. Web. doi:10.1016/j.cma.2019.05.010.
Fernandez, Felipe, Compel, W. Scott, Lewicki, James P., & Tortorelli, Daniel A. Optimal design of fiber reinforced composite structures and their direct ink write fabrication. United States. doi:10.1016/j.cma.2019.05.010.
Fernandez, Felipe, Compel, W. Scott, Lewicki, James P., and Tortorelli, Daniel A. Tue . "Optimal design of fiber reinforced composite structures and their direct ink write fabrication". United States. doi:10.1016/j.cma.2019.05.010. https://www.osti.gov/servlets/purl/1598959.
@article{osti_1598959,
title = {Optimal design of fiber reinforced composite structures and their direct ink write fabrication},
author = {Fernandez, Felipe and Compel, W. Scott and Lewicki, James P. and Tortorelli, Daniel A.},
abstractNote = {The majority of the current structural optimization software does not accommodate manufacturing constraints. Therefore, substantial modifications are imposed upon optimized designs to make them manufacturable and hence nonoptimal. We propose to optimize the design of composite structures that are amenable to Additive Manufacturing (AM). The printing process chosen in our study is based on Direct Ink Writing (DIW) in which short carbon fibers in a thermoset resin are extruded through a moving nozzle to build up a structure. Since the fibers are primarily aligned in the flow direction of the extrudate, the DIW printing trajectory influences the material properties of the composite structure. To accommodate this, the extrudate trajectory follows the contours of parameterized level-set functions. The parametrization allows us to prescribe the material properties and impose many DIW manufacturing constraints such as no-overlap, no-sag, minimum radius of curvature and continuity of the toolpaths. Ultimately, we obtain optimal manufacturable toolpaths that start and finish at a boundary. To minimize the fabrication time, we formulate the linking sequence of the toolpaths as a traveling salesman problem which we solve to obtain the shortest continuous toolpath per layer. Several examples illustrate the optimization procedure. Validation is also performed.},
doi = {10.1016/j.cma.2019.05.010},
journal = {Computer Methods in Applied Mechanics and Engineering},
issn = {0045-7825},
number = C,
volume = 353,
place = {United States},
year = {2019},
month = {5}
}

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