A torsion test for the study of the large deformation recovery of shape memory polymers

A torsion device was designed and built for testing the shape fixity and shape recovery of shape memory polymers at large deformations. A simple thermal chamber was used to regulate the thermal environment during testing and a CCD camera was used for recording the deformation. Such a torsion testing system provided a quantitative estimate of the kinematics and kinetics of shape recovery for samples submitted to large deformations at moderate strains that are more likely to be expected in actual shape memory applications. In addition, such measurements are complementary to those obtained from large strain uniaxial tension tests usually used during traditional shape memory effect characterization. As a result, the torsional shape memory testing device and testing method described is expected to contribute to building complementary data for the thermomechanical modeling of shape memory polymers.