The continuous measurement of the damping and fatigue properties of high‐impact polystyrene with a controlled‐amplitude torsion pendulum

摘要

AbstractTorsional damping and fatigue studies were made on high‐impact polystyrene using a controlled‐amplitude, continuously recording torsion pendulum. The damping behavior was measured as a function of the angular displacement, axial tensile stress, and the number of repeated cycles. At a critical axial tensile stress, the damping behavior changed from amplitude‐independent to amplitude‐dependent behavior. Damping measurements on high‐impact polystyrene specimens that had been previously crazed in tension showed that both the damping and the tensile stress necessary to produce amplitude‐dependent damping varied with the orientation of the craze. Repeated cycling of HIPS specimens produced crazing and amplitude‐dependent damping at a tensile stress below that expected from simple static tensile loading. Scanning electron micrographs of fracture surfaces from these specimens revealed that the rubber particles could be clearly distinguished from the surro