Mechanical structure-property relationship of aerogels

Ma, Hang-Shing, Roberts, Anthony P., Prevost, Jean-H., Jullien, Rémi and Scherer, George W. (2000) Mechanical structure-property relationship of aerogels. Journal of Non-Crystalline Solids, 277 2-3: 127-141. doi:10.1016/S0022-3093(00)00288-X

Author Ma, Hang-Shing
Roberts, Anthony P.
Prevost, Jean-H.
Jullien, Rémi
Scherer, George W.
Title Mechanical structure-property relationship of aerogels
Journal name Journal of Non-Crystalline Solids   Check publisher's open access policy
ISSN 0022-3093
Publication date 2000-11-01
Sub-type Article (original research)
DOI 10.1016/S0022-3093(00)00288-X
Open Access Status Not Open Access
Volume 277
Issue 2-3
Start page 127
End page 141
Total pages 15
Place of publication Amsterdam, The Netherlands
Publisher Elsevier Science
Language eng
Subject C1
240202 Condensed Matter Physics - Structural Properties
780102 Physical sciences
Abstract The elastic moduli (E) of high-porosity materials (such as aerogels) exhibit power-law scaling with their relative densities (rho), E proportional to rho (m)(,) where 3 less than or equal to m less than or equal to 4, but the physics responsible for this behavior is not well-understood, Computer models of aerogels were generated by diffusion-limited cluster-cluster aggregation (DLCA) algorithms, and their linear elastic properties were examined by the finite element method (FEM), assuming that the stiffness of each interparticle bond can be represented by a beam element. The simulation yields m approximate to 3.6 for perfectly connected structures, contradicting the consensus that the dangling mass on the gel gives rise to the exponent. The results suggest that the high exponent is largely because of the reduction in the connectivity of the material with decreasing density. The open-cell foam model, which predicts m = 2, is valid only when the connectivity remains unchanged upon variation of the density. The mechanical structure-property relationship in the gel can be described by the 'blob-and-link' model. The bonds (links) between the fractal clusters (blobs) are more sparsely distributed than those inside the clusters, and therefore the strain energy is localized at the cluster boundaries during deformation. This model is consistent with the experimental evidence. (C) 2000 Elsevier Science B.V. All rights reserved.
Keyword Materials Science, Ceramics
Materials Science, Multidisciplinary
Elastic Properties
Silica Aerogels
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Microscopy and Microanalysis Publications
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Citation counts: TR Web of Science Citation Count  Cited 82 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 10 Jun 2008, 21:22:06 EST