A level set-based topology optimization method targeting metallic waveguide design problems

Shintaro Yamasaki*, Tsuyoshi Nomura, Atsushi Kawamoto, Kazuo Sato, Shinji Nishiwaki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)

Abstract

In this paper, we propose a level set-based topology optimization method targeting metallic waveguide design problems, where the skin effect must be taken into account since the metallic waveguides are generally used in the high-frequency range where this effect critically affects performance. One of the most reasonable approaches to represent the skin effect is to impose an electric field constraint condition on the surface of the metal. To implement this approach, we develop a boundary-tracking scheme for the arbitrary Lagrangian Eulerian (ALE) mesh pertaining to the zero iso-contour of the level set function that is given in an Eulerian mesh, and impose Dirichlet boundary conditions at the nodes on the zero iso-contour in the ALE mesh to compute the electric field. Since the ALE mesh accurately tracks the zero iso-contour at every optimization iteration, the electric field is always appropriately computed during optimization. For the sensitivity analysis, we compute the nodal coordinate sensitivities in the ALE mesh and smooth them by solving a Helmholtz-type partial differential equation. The obtained smoothed sensitivities are used to compute the normal velocity in the level set equation that is solved using the Eulerian mesh, and the level set function is updated based on the computed normal velocity. Finally, the utility of the proposed method is discussed through several numerical examples.

Original languageEnglish
Pages (from-to)844-868
Number of pages25
JournalInternational Journal for Numerical Methods in Engineering
Volume87
Issue number9
DOIs
Publication statusPublished - 2011 Sep 2
Externally publishedYes

Keywords

  • Arbitrary Lagrangian Eulerian method
  • Level set method
  • Metallic waveguide
  • Smoothed sensitivity
  • Topology optimization

ASJC Scopus subject areas

  • Numerical Analysis
  • Engineering(all)
  • Applied Mathematics

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