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Estimates for the localised stiffness and heterogeneity of auxetic foams
Author(s) -
Gaspar N.
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200777702
Subject(s) - auxetics , anisotropy , stiffness , microstructure , materials science , linear elasticity , symmetry (geometry) , finite element method , composite material , structural engineering , geometry , mathematics , physics , engineering , optics
In the task to accurately model auxetic foams, a number of details must be correctly accounted for. Firstly, the microstructure is not simple and can only be qualitatively described by traditional, regular, cellular models. Computed tomography (CT) data has been used to begin to describe the details of the complex geometry of the foams' microstructure and to describe it in a manner suitable for advanced models. Using these modelling techniques that are able to capture difficult geometries, values of the local and global mechanical properties are calculated. These mechanical calculations are based on a linear elastic core and global properties are a mean strain estimate. The latter is shown to be inadequate, highlighting the need for a heterogeneous basis for accurate modelling. The significant mechanical anisotropy of the material is reported and mechanical results are recast according to axis of major and minor principal stiffness demonstrating the elastic symmetry of the foam and a requirement of an objective methodology in modelling an inherently anisotropic material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)