Experimental study on dynamic properties of polyurethane foam subjected to large strains and low strain rates

Dynamic compression tests for polyurethane foam were performed on an elongated split Hopkinson pressure bar setup, the incident bar of which was six meter long and the striker was eight decimeter long. A pulse shaper was used to achieve the dynamic balance in the stresses at the two sides of the specimens. About 600-microsecond pulses were experimentally obtained and the stress-strain curves of polyurethane foam were attained at the strain rate of 520 s-1 and the strain of 0.15. And the discussions were carried out for the relation of strain rate and stress balance at the two sides of the specimens.