ABSTRACT

As success is achieved in modeling individual aspects of rubber's stress strain response such as nonlinear elasticity, the Mullins effect, the Fletcher/Gent/Payne effect, and viscoelasticity, it is becoming possible to contemplate increasingly realistic models that simultaneously embody many aspects. This chapter presents the results of an experiment involving combined axial and shear cyclic straining. A typical material element of the test specimen is shown in the original and deformed states. The deformation history applied to the specimen features events that probe a number of different aspects of rubber's behavior. The first two events involve purely axial loading, first in the compressive direction, then in the tensile. The stress and strain states on the mid-plane can be inferred for the specimen from measurements of the applied force, torque, axial displacement, and twist, via relatively simple calculations. The values of the apparent stiffness and loss factor depend strongly on mean deformation.