Dynamic mechanical response of polystyrene at high strain rates under uniaxial strain ramp loading

Determination of yield strength of polymers under dynamic loading has proven to be extremely difficult. Up to now, few strength data have been obtained for polymers at strain rate above 10 5 /s. Based on the electromagnetically driven quasi-isentropic loading technique, the yield strength of polystyrene under high pressure and high strain rate was measured experimentally by pressure comparison method. In the experiment, a polystyrene window method is used to measure the in-situ particle velocity directly, which reduces the experimental error and obtains reliable high-pressure Lagrangian sound velocity and quasi-isentropic compression line. The yield stress of polystyrene under quasi-isentropic compression are measured continuously at pressure up to 4GPa and strain rate of 10 6 /s. Combined with strength data under quasi-static and intermediate strain rate loading, the strain rate effect of yield of polystyrene was analyzed. It was found that the yield strength of polystyrene has strain rate effect, but the “upturn” phenomenon was not observed. Additionally, the yield stress of polystyrene from 10 -3 /s to 10 6 /s strain rate can be fitted by Eyring model, which provides a reference for the study of physical properties of polymer materials under high strain rate loading.