The use of metal foam projectiles to simulate shock loading on a structure

Metal foam projectiles are used to generate dynamic pressure-time histories representative of shock loading in water and air. A 1D plastic shock wave analysis is performed for a foam projectile impacting a free but rigid mass. It is shown that the pressure versus time pulse exerted on the mass and the shock arrest distance within the foam depend upon the ratio of foam mass to impacted mass, and upon the ratio of quasi-static to hydrodynamic strength of the foam. The theory is supported by two sets of experiments, one where Alporas foam impacts an instrumented Kolsky pressure bar, and one where the foam is fired at a free mass. It is demonstrated that the magnitude and duration of the pressure pulse can be controlled by suitable adjustment of the velocity, length and density of the foam projectile.