High-speed testing and material modeling of unfilled styrene butadiene vulcanizates at impact rates

Abstract

High-speed tensile tests were performed on unfilled SBR strip and sheet specimens at room temperature. Uniaxial dynamic stress-extension ratio curves indicated three distinct regions of rate-dependent behavior when strain rates were below 180 s⁻¹, between 180–280 s⁻¹and above 280 s⁻¹. With increasing strain rate, the toughness increased in the first region, remained roughly constant in the second region, and decreased in the third region. Time-temperature shift on SBR near the glass transition temperature used to obtain high strain rate tensile strength at room temperature did not give the same results as those found in the impact tensile test. The dynamic toughness was used to predict failure of rubber sheets under impact loads using ABAQUS Explicit. Predicted values of the sheet extension at the onset of failure were within 10% of experimental values.