Abstract
A simple two-dimensional model for the deformation of auxetic microporous polymers (those with a negative Poisson's ratio) has been developed. This model network of rectangular nodules interconnected by fibrils has been further developed to include the possibilities of fibril hinging, flexure and stretching. Expressions for strain-dependent Poisson's ratio and Young's modulus have been derived and compared with experimental results on microporous PTFE and UHMWPE. A combination of the hinging mode followed by the stretching mode of deformation can be used to explain the general features of the experimental data for these auxetic polymers. The force coefficients governing the different modes of deformation are dependent on fibril dimensions and intrinsic material properties. By varying the geometry of the network, the model can be used to predict different combinations of Poisson's ratio with modulus, from large positive through to large negative values.
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References
K. E. EVANS, M. A. NKANSAH, I. J. HUTCHINSON and S. C. ROGERS, Nature 353 (1991) 124.
A. YEGANEH-HAERI, D. J. WEIDNER and J. B. PARISE, Science 257 (1992) 650.
N. R. KESKAR and J. R. CHELIKOWSKY, Nature 358 (1992) 222.
A. ALDERSON and K. E. EVANS (1994) in preparation.
B. D. CADDOCK and K. E. EVANS, J. Phys. D Appl Phys, 22 (1989) 1877.
K. E. EVANS and B. D. CADDOCK, ibid. 22 (1989) 1883.
K. L. ALDERSON and K. E. EVANS, Polymer 33 (1992) 4435.
R. LAKES, Science 235 (1987) 1038.
K. E. EVANS, M. A. NKANSAH and I. J. HUTCHINSON, Acta Metall. Mater. 42 (1994) 1289.
K. E. EVANS, Endeavour 15 (1991) 170.
K. L. ALDERSON, A. P. PICKLES, P. J. NEALE and K. E. EVANS, Acta Metall. Mater. 42 (1994) 2261.
K. E. EVANS, Chem. Ind. 20 (1990) 654.
K. L. ALDERSON and K. E. EVANS, J. Mater. Sci. 28 (1993) 4092.
P. J. NEALE, K. L. ALDERSON, A. P. PICKLES and K. E. EVANS, J. Mater. Sci. Lett. 12 (1993) 1529.
K.-E. EVANS, J. Phys. D Appl. Phys. 22 (1989) 1870.
B. D. CADDOCK, Private communication (1995).
J. E. SHIGLEY, “Applied Mechanics of Materials” (McGraw-Hill, New York, 1976).
B. M. LEMPRIERE. Am. Inst. Aeronaut. Astronaut. J. 6 (1968) 2226.
L. J. GIBSON, M. F. ASHBY, G. S. SCHAJER and C. I. ROBERTSON, Proc. R. Soc. Lond. A382 (1982) 25.
R. J. ROARK and W. C. YOUNG, “Formulas for Stress and Strain”, 5th Edn (McGraw-Hill, 1976).
K. L. ALDERSON and P. J. NEALE Private communication (1994).
POLYGRAF, Molecular Simulations Inc., 199 South Los Robles Avenue, Suite 540, Pasadena, CA 91101, USA.
R. L. MCGEE and J.R. COLLIER, Polym. Eng. Sci. 26 (1986) 239.
K. E. EVANS and K. L. ALDERSON, J. Mater. Sci. Lett. 11 (1992) 1721.
S. L. HSU and S. KRIMM, J. Appl. Phys. 48 (1977) 4013.
R. J. SCHAUFELE and T. SHIMANOUCHI, J. Chem. Phys. 47 (1967) 3605.
L. HOLIDAY and J. W. WHITE, Pure Appl. Chem. 26 (1971) 545.
“Polygraf User's Manual”, Molecular Simulations Inc., 199 South Los Robles Avenue, Suite 540, Pasadena, CA 91101, USA.
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Alderson, A., Evans, K.E. Microstructural modelling of auxetic microporous polymers. Journal of Materials Science 30, 3319–3332 (1995). https://doi.org/10.1007/BF00349875
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DOI: https://doi.org/10.1007/BF00349875