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Two Methods for Analyzing Waves in Composites with Random Microstructure

Published online by Cambridge University Press:  25 February 2011

John R. Willis*
Affiliation:
School of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom
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Abstract

The problem of calculating the mean wave in a composite with random microstructure is addressed. Exact characterizations of the problem can be given, in the form of stochastic variational principles. Substitution of simple configuration-dependent trial fields into these generates approximations which are, in a sense, ‘optimal’. It is necessary in practice to employ only trial fields which will generate, in the variational principle, no more statistical information than is actually available. Trial fields that require knowledge of two-point statistics generate equations that can also be obtained directly, through use of the QCA. The same fields can be substituted into an alternative variational principle to yield an approximation that makes use of three-point statistics – this approximation is less easy to obtain by direct reasoning. When not even two-point information is available, some more elementary approximation is needed. One such approximation, which is simple and direct in its application, is an extension to dynamics of a “self-consistent embedding” scheme which is widely used in static problems. This is also discussed, together with some illustrative results for a matrix containing inclusions and for a polycrystal.

Type
Research Article
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

1. Kantor, Y. and Bergmann, D. J., J. Mech. Phys. Solids 32, 41 (1984).Google Scholar
2. Milton, G. W., Comm. Pure Appl. Math. 43, 63 (1990).Google Scholar
3. Willis, J. R., J. Mech. Phys. Solids 25, 185 (1977).CrossRefGoogle Scholar
4. Willis, J. R., Advances in Applied Mechanics 21, edited by Yih, C. S. (Academic Press, New York, 1981) pp. 178.Google Scholar
5. Talbot, D. R. S. and Willis, J. R., IMA J. Appl. Math. 35, 39 (1985).CrossRefGoogle Scholar
6. Castafieda, P. Ponte and Willis, J. R., Proc. R. Soc. Lond. A 416, 217 (1988).Google Scholar
7. Talbot, D. R. S. and Willis, J. R., Int. J. Solids Struct., in the press.Google Scholar
8. Budiansky, B., J. Mech. Phys. Solids 13, 223 (1965).Google Scholar
9. Hill, R., J. Mech. Phys. Solids 13, 213 (1965).CrossRefGoogle Scholar
10. Varadan, V. K., Varadan, V. V. and Pao, Y. H., J. Acoust. Soc. Amer. 63, 1310 (1978).CrossRefGoogle Scholar
11. Tsang, L. and Kong, J. A., J. Appl. Phys. 52, 5448 (1981).Google Scholar
12. Lax, M., Phys. Rev. 85, 621 (1952).Google Scholar
13. Hashin, Z. and Shtrikman, S., J. Mech. Phys. Solids 10, 335 (1962).Google Scholar
14. Willis, J. R., Mechanics of Solids, the Rodney Hill 60th Anniversary Volume, edited by Hopkins, H. G. and Sewell, M. J. (Pergamon Press, Oxford, 1982) pp. 653686.Google Scholar
15. Willis, J. R., Wave Motion 3, 1 (1981).Google Scholar
16. Gurtin, M. E., Arch. Rat. Mech. Anal. 16, 34 (1964).Google Scholar
17. Willis, J. R., J. Mech. Phys. Solids 28, 307 (1980).Google Scholar
18. Willis, J. R., Variational Methods in Mechanics of Solids, edited by Nemat-Nasser, S. (Pergamon Press, New York, 1980) pp. 5966.Google Scholar
19. Willis, J. R., Continuum Models of Discrete Systems 4, edited by Brulin, O. and Hsieh, R. K. T. (North-Holland, Amsterdam, 1981), pp. 471478.Google Scholar
20. Milton, G. W. and Phan-Thien, N., Proc. R. Soc. Lond. A 380, 385 (1982).Google Scholar
21. Willis, J. R., Int. J. Solids Struct. 21, 805 (1985).Google Scholar
22. Sabina, F. J. and Willis, J. R., Wave Motion 10, 127 (1988).Google Scholar
23. Sabina, F. J. and Willis, J. R., submitted for publication.Google Scholar
24. Papadakis, E. P., J. Acoust. Soc. Amer. 37, 711 (1965).Google Scholar