Experiments on the Mechanics of Rubber II: The Torsion, Inflation and Extension of a Tube

The formulae derived by Rivlin (1949) for the forces necessary to produce simple extension, radial inflation and torsion in a tube of incompressible highly elastic material, which is isotropic in its undeformed state, are specialized to the case when the amount of torsion is small The resulting formulae are compared with measurements on tubes of vulcanized natural rubber and conclusions as to the form of the stored-energy function are drawn, in general agreement with those reached from earlier experiments The experiments indicate that hysteresis between the loading and unloading curves for the vulcanizate is associated with certain terms in the expression for its stored-energy function and, presumably, with the mechanism which accounts for the presence of these terms