Fatigue behavior of an epoxy polymer subjected to cyclic shear loading

Strain-range-controlled fully reversed cyclic shearing fatigue tests have been performed on thin-walled tubular specimens made of an epoxy polymer. The engineering shear strain was measured by a non-contact real-time strain measurement and control system recently developed in our lab. The synchronized stress–strain data were recorded by the system for full lives of the specimens. Therefore evolutions of mechanical properties of the epoxy polymer during fatigue process could be analyzed based on the retrieved stress–strain data. It was found that life data of the shearing fatigue tests were well correlated with the uniaxial fatigue test data of the material by using the suggested stress-, strain- or strain-energy-density-based multiaxial fatigue criteria.