Experimental and simulated high strain dynamic loading of polyurethane foam

A test methodology was developed to examine polyurethane foam specimens up to 25 mm thick at strain rates ranging from quasi-static to high rate dynamic (2,600 1/s) at high strain levels (>80%). This was accomplished using a modified Hopkinson bar setup and projectile to dynamically load the foam specimens. A high-speed video camera was used to observe the deformation response at 95,238 frames per second. Strain derived through pixel scaling in the high-speed video was used to create the strain history plots at dynamic loading rates. Experimental data indicated that the polyurethane foam is strain rate sensitive which was also validated using finite element models of the impact event.