Abstract/Details

Topology optimization of geometrically nonlinear structures including thermo-mechanical coupling


2006 2006

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Abstract (summary)

The goal of this research is to develop an efficient and robust methodology for the topology optimization of geometrically nonlinear structures actuated by thermal expansion. The corotational finite element method is used to model the geometric nonlinearity because its element independent nature and linear elastic element core provide a flexibility to introduce thermal loads and formulate analytical sensitivities for any element type. To create thermal expansion, this work uses both prescribed temperature changes and localized heat generation via Joule heating, where electrical and thermal conduction are additionally considered. In this coupled multi-physics problem, emphasis is put on material models and coupling to maintain accuracy and efficiency. One-way coupling is shown to be equivalent to a small strain assumption, and the proper modeling of convection properties in topology optimization is addressed. To model the thermal and electrical conduction in planar layered materials, an averaged (smeared) model based on the smoothed properties of the individual layers is introduced. Large displacement structures are prone to exhibit buckling and limit point behavior. To include instabilities in topology optimization, specialized techniques are introduced to overcome inherent numerical difficulties. A nodal density transformation is introduced to isolate structurally relevant eigenmodes, and a homotopy between linear and nonlinear finite elements is provided to limit the effects of mesh distortion. The proposed methodology is successfully applied to micro-mechanism applications capable of a three-dimensional range of motion, including novel designs reflective of the manufacturing technology used in the micro-electro-mechanical (MEMS) community.

Indexing (details)


Subject
Aerospace materials
Classification
0538: Aerospace materials
Identifier / keyword
Applied sciences; Geometrically nonlinear structures; Thermomechanical coupling; Topology
Title
Topology optimization of geometrically nonlinear structures including thermo-mechanical coupling
Author
Pajot, Joseph M.
Number of pages
203
Publication year
2006
Degree date
2006
School code
0051
Source
DAI-B 67/05, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542684005
Advisor
Maute, Kurt
University/institution
University of Colorado at Boulder
University location
United States -- Colorado
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3219000
ProQuest document ID
305354493
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305354493
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