Effect of shock compressibility on the high-velocity collision between a rigid body and a porous medium

The high-velocity collision between a rigid body and a porous medium is examined in the context of a hydrodynamic model, with particular attention given to the effect of shock compressibility. It is shown that, at supersonic velocities, the resistance of a porous obstacle with a porosity of 30 percent is close to that of a dense solid obstacle of the same composition. This finding is relevant to the determination of the depth of the crater formed in a porous material in the case of high-velocity impact. Experimental results are presented for the high-velocity (3 km/s) penetration of solid copper indenters into porous copper targets with porosities of 8, 15, 24, 35, and 45 percent.