High strain‐rate shear deformation of a polyurethane elastomer subjected to impact loading

Experimental techniques have been developed to produce and measure large amplitude one dimensional compression and shear waves in a polyurethane elastomer (Solithane 113). Experimental measurements consisted of time‐resolved compression and shear amplitude measurements at different distances from the impact surface. The data were analyzed to provide compression and shear wave velocities, and the corresponding stress‐stain curves on the microsecond time scale. The ability to measure directly the high stain rate shear response is a new development and has provided interesting results. The shear modulus varies between 3 and 9 kbar for compressive stresses ranging between 2 and 14 kbar. In contrast, shear modulus values inferred from quasi‐static measurements of bulk and Young's modulus under static high pressure are negligible. These comparisons suggest a high rate dependence of shear modulus in the glassy state. The shear strain curves suggest an elastic‐plastic response with yield strengths ranging from 0.12 kbar to 0.25 kbar with increasing compression for the compressive stress range investigated. Results of compression experiments are also presented.