MATERIAL BEHAVIOR IN PLANE POLYURETHANE-POLYURETHANE IMPACT WITH VELOCITIES FROM 10 TO 400 M SEC/

Shock response of the rubber-like polyurethane (PU) has been studied i n symmetrical plane/impact experiments in the impact velocity range 10 -400 m/sec. The free surface velocity of the samples was measured by t he laser velocity interferometer. It has been found that for a weak im pact the step-like perturbation cannot penetrate into the polyurethane sample while the signal with the risetime of 1 mu sec and higher may propagate in the material with some steepening. The Poisson's ratio of PU estimated on the basis of the weak-impact data is close to 0.5. Wi th the increase of the impact strength the PU shock response becomes m ore similar to that of a normal solid with Poisson's ratio 0.39.