Recent Advances in the Phenomenological Theory of Rubber Elasticity

Abstract

Abstract We have shown that representations for the strain-energy function in terms of the stretches λ1, λ1, λ1, with particular reference to the Valanis-Landel hypothesis, provide a very good correspondence between theoretical stress-deformation relations and existing experimental data for a variety of different deformations of rubberlike materials. The stress-deformation relations themselves have a simple structure which makes for clear interpretation of the experimental results. As was emphasized in Section II.B., however, more data from biaxial tests on rubberlike materials of varying constitution are needed to support those already available. Also, further data from a variety of different experiments in which inhomogeneous deformations occur would be valuable. Finally, with reference to the effects of compressibility, data relating to volume changes—possibly from biaxial tests in the presence of hydrostatic pressure—would enable a more systematic approach to the construction of strain-energy functions for compressible materials to be pursued.