High Strain-Rate Tensile Characterization of EPDM Rubber Using Non-equilibrium Loading and the Virtual Fields Method

作者：Yoon S h^*; Winters M; Siviour C R

来源：Experimental Mechanics, 2016, 56(1): 25-35.

DOI：10.1007/s11340-015-0068-3

• Elastomers
• High strain rate
• Finite deformation
• Tensile
• Mechanical characterization
• Virtual fieldsmethod
• Inverse method

The dynamic tensile stress-strain behaviour of an EPDM rubber was characterized at quasi-static (< 0.01 s(-1)), medium and high strain rates (100-600 s(-1)). The quasi-static experiments were conducted by a simple uniaxial tensile test; the medium and high strain-rate tests were performed using drop-weight and gas-gun apparatuses. In these dynamic tests, high speed imaging and digital image correlation were used to measure dynamic displacement fields in the specimen. The dynamic stress state is not in equilibrium, which is a usual requirement for a conventional dynamic experimental analysis. Instead, the non-equilibrium deformation was analysed by the Virtual Fields Method (VFM) using inertial forces, clearly generated due to the non-equilibrium state, as a virtual load cell. The linear VFM associated with a linear isotropic model was applied to the drop-weight test data, in these experiments specimens were subjected to various static pre-stretches before dynamic loading was applied. For the gas gun experiments, in which the dynamic strain and experimental durations were larger, the nonlinear VFM was developed to include the one-term Ogden hyperelastic model so that the long deformation history could be analysed. The material parameters identified by these two techniques were used to reconstruct uniaxial true stress-strain curves which showed a clear and consistent rate dependency.

• 出版日期2016-1