Determining the strength of filled epoxy from ballistic experiments

This paper analyzes the results of experiments with impact of metal spherical impactors on cylindrical targets of epoxy (filled with Al$_2$O$_3$ microparticles and without the filler) performed in a ballistic range. Impact velocities were limited to a range of 0.6–1.1 km/sec since higher velocities led to complete destruction of the targets. Impacts at the velocities considered produced channels of an almost cylindrical shape with the impactor stuck at the end of the channel. The strength of filled epoxy is estimated using the previously established dependence of the channel depth on the impact energy, the ratio of the densities of the impactor and target materials, and the tensile strength of the target material. It is found that at a mass fraction of the filler equal to 0.4, the strength of the target increased by a factor of approximately 1.5–2.