Rubber Elasticity and Fracture

Abstract

Rubber is an amorphous elastomer of high entropy that is normally treated by statistical thermodynamics instead of molecular modeling. A pseudo-amorphous model is introduced that is useful in extending true stress-true strain uniaxial tensile results to other more complex states of stressing. While the statistical thermodynamic approach is still needed to deal with thermal aspects of rubber elasticity, the new approach represents a simpler, more accurate method of dealing with mechanical properties. Fracture of rubber follows a criterion of constant engineering strain (or constant extension ratio) in the resultant principal stress direction which is consistent with the proposed model and the experimental results presented.