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Thin Metastructures with Engineered Thermal Expansion


Gdoutos, Eleftherios E. (2013) Thin Metastructures with Engineered Thermal Expansion. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/M69R-3A76.


The geometry and constituent materials of metastructures can be used to engineer the thermal expansion coefficient. In this thesis, we design, fabricate, and test thin thermally stable metastructures consisting of bi-metallic unit cells and show how the coefficient of thermal expansion (CTE) of these metastructures can be finely and coarsely tuned by varying the CTE of the constituent materials and the unit cell geometry. Planar and three-dimensional finite element method modeling is used to drive the design and inform experiments, and predict the response of these metastructures. We demonstrate computationally the significance of out-of-plane effects in the metastructure response. We develop an experimental setup using digital image correlation and an infrared camera to experimentally measure full displacement and temperature fields during testing and accurately measure the metastructures’ CTE. We experimentally demonstrate high aspect ratio metastructures of Ti/Al and Kovar/Al which exhibit near-zero and negative CTE, respectively. We demonstrate robust fabrication procedures for thermally stable samples with high aspect ratios in thin foil and thin film scales. We investigate the lattice structure and mechanical properties of thin films comprising a near-zero CTE metastructure. The mechanics developed in this work can be used to engineer metastructures of arbitrary CTE and can be extended to three dimensions.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:low cte; metastructures; negative cte
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Daraio, Chiara
Thesis Committee:
  • Pellegrino, Sergio (chair)
  • Ravichandran, Guruswami
  • Daraio, Chiara
  • Shapiro, Andrew A.
Defense Date:24 April 2013
Non-Caltech Author Email:gdoutos (AT)
Record Number:CaltechTHESIS:05292013-162505920
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7765
Deposited By: Eleftherios Gdoutos
Deposited On:30 May 2013 23:44
Last Modified:08 Nov 2023 00:21

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