POST YIELD PHENOMENA IN TENSILE TESTS ON POLYVINYL-CHLORIDE)

Tensile tests have been made on poly(vinyl chloride) to find the conditions under which uniform extension, diffuse necking, localized necking or thermal fracture occur. These observations have been compared with the predictions of a finite element model of the tensile test specimen to ascertain the causes of the changes in post-yield behaviour with increased crosshead speed. The major effect of increased crosshead speed is to reduce the dissipation of heat generated by plastic deformation. The effect of thermal pre-treatment of the PVC is to change the extent of strain softening after yield, and thereby control the range of post-yield phenomena that are possible. © 1979.