Hostname: page-component-848d4c4894-wg55d Total loading time: 0 Render date: 2024-05-15T23:41:31.976Z Has data issue: false hasContentIssue false

Inequalities associated with the inversion of elastic stress-deformation relations and their implications

Published online by Cambridge University Press:  24 October 2008

R. W. Ogden
Affiliation:
School of Mathematics, University of Bath

Abstract

For an elastic solid the constitutive law can be written in terms of the deformation gradient α and its conjugate nominal stress ss(α), and also in terms of the right stretch u and its conjugate stress τ ≡ τ(u). It is shown that for isotropic elastic solids s(α) is invertible, in the local sense, for all u in the domain of u-space where τ(u) is locally invertible, with the exception of certain configurations which correspond to planes in τ-space.In the global sense a given s corresponds to four distinct τ's, and s is invertible to give four distinct α's when the corresponding τ's are uniquely invertible. That there are four branches of the inversion α(s) is of fundamental importance in that it clarifiesthe extent to which non-uniqueness of solution of boundary-value problems can be expected.

The implications of these results in respect of the complementary variational principle are discussed, and the controversy surrounding the use of nominal stress in this principle resolved.

Consequences of the required restrictions on τ(u) are examined and discussed in relation to inequalities which may be regarded as entailing physically reasonable response. It is intimated that τ(u) is invertible in the domain of elastic response.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1977

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Hill, R.On constitutive inequalities for simple materials I. J. Mech. Phys. Solids 16 (1968), 229.CrossRefGoogle Scholar
(2)Biot, M. A.The mechanics of incremental deformations (New York, John Wiley, 1965).CrossRefGoogle Scholar
(3)Koiter, W. T.On the principle of stationary complementary energy in the non-linear theory of elasticity. SIAM J. Appl. Math. 25 (1973), 424.CrossRefGoogle Scholar
(4)Koiter, W. T. On the complementary energy theorem in non-linear elasticity theory. Trends in applications of pure mathematics to mechanics, ed. Fichera, G. (London, Pitman, 1976).Google Scholar
(5)Christoffersen, J. On Zubov's principle of stationary complementary energy and a related principle. Report no. 44, Danish Centre for Applied Mathematics and Mechanics (1973).Google Scholar
(6)Dill, E. H. The complementary energy principle in non-linear elasticity. Report no. 74–1, College of Engineering, University of Washington (1974).Google Scholar
(7)Fraeijs, De Veubeke B. M.A new variational theorem for finite elastic displacements. Internat. J. Engrg. Sci. 10 (1972), 745.Google Scholar
(8)Ogden, R. W.A note on variational theorems in non-linear elastostatics. Proc. Cambridge Philos. Soc. 77 (1975), 609.CrossRefGoogle Scholar
(9)Hill, R.On the elasticity and stability of perfect crystals at finite strain. Proc. Cambridge Philos. Soc. 77 (1975), 225.CrossRefGoogle Scholar
(10)Hill, R.Eigenmodal deformations in elastic/plastic continua. J. Mech. Phys. Solids 15 (1967), 371.CrossRefGoogle Scholar
(11)Truesdell, C. and Noll, W. The non-linear field theories of mechanics. Handbuch der Physik, vol. III/3, ed. Flügge, S. (Berlin, Heidelberg, New York, Springer-Verlag, 1965).Google Scholar
(12)Hill, R.Constitutive inequalities for isotropic elastic solids under finite strain. Proc. Roy. Soc. London Ser. A 314 (1970), 457.Google Scholar
(13)Ogden, R. W.Large deformation isotropic elasticity: on the correlation of theory and experiment for compressible rubberlike solids. Proc. Roy. Soc. London Ser. A 328 (1972), 567.Google Scholar
(14)Jones, D. F. and Treloar, L. R. G.The properties of rubber in pure homogeneous strain. J. Phys. D: Appl. Phys. 8 (1975), 1285.CrossRefGoogle Scholar
(15)Gent, A. N. and Lindley, P. B.Internal rupture of bonded rubber cylinders in tension. Proc. Roy. Soc. London Ser. A 249 (1959), 195.Google Scholar
(16)Krawietz, A.A comprehensive constitutive inequality in finite elasticstrain. Arch. Rational Mech. Anal. 58 (1975), 127.CrossRefGoogle Scholar