Advertisement

Journal of Materials Science

, Volume 32, Issue 21, pp 5725–5736 | Cite as

Microscopic examination of the microstructure and deformation of conventional and auxetic foams

  • N CHAN
  • K. E EVANS
Article

Abstract

Auxetic materials have a negative Poisson’s ratio, that is, they expand laterally when stretched longitudinally. One way of obtaining a negative Poisson’s ratio is by using a re-entrant cell structure. Auxetic foam was fabricated from a conventional polymeric foam. Assuming similar mechanical properties for the solid material comprising the foams, the principle variable affecting the properties of the foam is the geometry of the cells. This means that the unusual mechanical properties of auxetic foams are attributed to the deformation characteristics of re-entrant microstructures. In this paper, the results of optical- and scanning electron-microscopic studies of the geometrical parameters for the different foams examined are presented. Examples of the microstructural deformation mechanisms observed are also presented. Comparison between the conventional foams and their auxetic conversions are also made.

Keywords

Foam Urethane Urethane Foam Rise Direction Auxetic Material 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. S. LAKES, Science 235 (1987) 1038.CrossRefGoogle Scholar
  2. 2.
    A. E. H. LOVE, Phil. Trans. 10 (1891) 393.Google Scholar
  3. 3.
    R. S. LAKES, Adv. Mater. 5 (1993) 293.CrossRefGoogle Scholar
  4. 4.
    B. D. CADDOCK and K. E. EVANS, J. Phys. D22 (1989) 1870.Google Scholar
  5. 5.
    K. L. ALDERSON and K. E. EVANS, Polym. 33 (1992) 4435.CrossRefGoogle Scholar
  6. 6.
    A. P. PICKLES, K. L. ALDERSON and K. E. EVANS, Polym. Engng Sci. 36 (1996) 636.CrossRefGoogle Scholar
  7. 7.
    K. E. EVANS, M. A. NKANSAH, I. J. HUTCHINSON and S. C. ROGERS, Nature 353 (1991) 124.CrossRefGoogle Scholar
  8. 8.
    L. J. GIBSON and M. F. ASHBY, “Cellular solids: structure and properties”, (Pergamon Press, London, 1988).Google Scholar
  9. 9.
    K. W. SUH and R. E. SKOCHDOPOLE, in “Encyclopedia of chemical technology”, Vol. 2, edited by M. Grayson, 3rd Edn (Wiley, New York, 1980) p. 82.Google Scholar
  10. 10.
    N. CHAN, PhD thesis, University of Liverpool (1995).Google Scholar
  11. 11.
    N. CHAN and K. E. EVANS, J. Mater. Sci. 32 (1997).Google Scholar
  12. 12.
    A. N. GENT and A. G. THOMAS, J. Appl. Polym. Sci. 1 (1959) 107.CrossRefGoogle Scholar

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • N CHAN
    • 1
  • K. E EVANS
    • 2
  1. 1.Institute of Aeronautics and AstronauticsNational Cheng Kung UniversityTainanTaiwan
  2. 2.School of Engineering, Harrison Engineering BuildingThe University of ExeterExeterUK

Personalised recommendations