Describing Large Deformation of Polymers at Quasi-static and High Strain Rates

Abstract

Polymeric materials such as elastomers and semi-crystalline polymers are widely used in industry, and many products and components made of them are subjected to impact loading and shocks. In this study, a visco-hyperelastic constitutive equation incorporating a strain-dependent relaxation time function is proposed to describe the large compressive and tensile deformation response of incompressible elastomeric materials. The model is applied to describe the response of six types of elastomer with different hardnesses. A thermo-mechanical constitutive model is also proposed to describe the quasi-static and high rate large-deformation response of semi-crystalline polymers. This model is developed based on an elastic-viscoelastic-viscoplastic framework, to predict the temperature and rate-dependent response of an incompressible semi-crystalline polymer, Nylon 6. Material sam?ples are subjected to high strain rate compressive and tensile loading using Split Hopkinson Bar devices, and they exhibit a temperature increase, which induces phase transition at the glass transition temperature.