Failure of a steel spherical particle upon impact on high-porous sheets

The failure of a 2-mm-diameter steel particle upon normal impact with a velocity of 1.5–7.3 km/sec onsheets 1 mm thick was studied. Two types of sheets were used: continuous sheets of Duralumin and high-porous sheets of a copper powder. The depth of the largest crater and the positions, areas, and effective diameters of all craters were measured on the witness plate. Values of the threshold impact velocities for the beginning of failure of the steel particle and distributions of the number of craters in size and radius from the impact point were obtained for various impact velocities. It is shown that at identical impact pressures near the failure threshold, the low-density high-porous sheets break up the steel particle better than the Duralumin sheets. This is possibly caused by the thermal explosion of the sheet material in the collision region, which increases the time of interaction of the impactor with the sheet.