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Journal of Materials Science

, Volume 44, Issue 4, pp 985–991 | Cite as

Model and analysis of size-stiffening in nanoporous cellular solids

  • Jun Wang
  • David C. C. LamEmail author
Article

Abstract

The size of the struts in nanoporous cellular solids typically has a secondary influence on the stiffness of the solids, but it leads to significant stiffening when it is on the same order as the higher-order material parameter. We examined this size-dependence using the higher-order finite-element method (FEM) in this study. Mathematical analysis showed that the displacement field that satisfies the conventional Lame equation can serve as a displacement field template in higher-order FEM. Benchmarking studies showed that results from simulations of beam bending and rod torsion using this FEM approach were in good agreement with results from analytical solutions and experiments. Using this approach, we showed that the stiffness of cellular solids is strongly affected by the cellular arrangement and the density when the cell size is on the order of the higher-order material parameter and that the stiffening behavior in nanoporous polyimide can be explained using higher-order theory. The FEM results also showed that a porous solid with half the weight can be engineered to become as stiff as a fully dense solid if the porous microarchitecture is tailored to take advantage of higher-order stiffening.

Keywords

Polyimide Strain Gradient Couple Stress Couple Stress Theory Length Scale Parameter 

Notes

Acknowledgement

Jun Wang acknowledges support from the Shanghai Leading Academic Discipline Project (Project Number: B113). DCC Lam acknowledges funding support (615007, 615505, HKUST6190/03E) from the Research Grants Council of the HKSAR, China.

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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Department of Materials ScienceFudan UniversityShanghaiPeople’s Republic of China
  2. 2.Department of Mechanical EngineeringThe Hong Kong University of Science and TechnologyKowloonHong Kong

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