Abstract

A method for characterizing rubber vulcanizates for engineering design analysis is described. The material characterization is based on the elastic strain energy functions expressible in terms of both Mooney‐Rivlin and Valanis‐Landel types of formulation. The specimens are flat sheets and long thin cylinders. Considering both accuracy of the predicted stress‐strain results and testing time, the pure shear method is preferred over other forms of biaxial loading. This method was automated using an MTS testing machine equipped with a PDP 11/04 mini‐computer. A filled vulcanizate under load exhibits progressive stress‐softening before it reaches an equilibrium state; this behavior was incorporated into the automatic testing procedure to ensure consistent and reproducible results. The adequacy and accuracy of the material coefficients derived from this method were checked against measured results and found to be satisfactory.