Application of the plane simple shear test for determination of the plastic behaviour of solid polymers at large strains

A simple shear test apparatus was designed and used in experiments for determining the plastic behavior of various amorphous and semicrystalline polymers at large shear strains. The geometry and dimensions of the specimens were determined after a critical evaluation of the test conditions, so as to avoid plastic buckling of the specimens, and to minimize undesirable stresses at the specimen ends. The kinematics of large deformation simple shear is discussed and relations between the stress and the finite strain tensors is presented, with particular attention being paid to the development of normal stresses. The problem of end effects is also investigated.