Dimensionally scaled penetration experiments to extract projectile sizes from space exposed surfaces

Impact experiments were conducted which employed soda-lime glass projectiles (50, 150, 1000 and 3175 μm in diameter; D_p) and aluminum (1100 series) and Teflon (FEP) targets of variable thickness (T; ranging from thick infinite halfspace targets D_p/T < 0.1] to foil thicknesseof a few microns D_p/T > 100]). The objectives of these impact experiments were determine, at constant impact velocity, the relationships between the diameter of the resulting penetration hole (D_h), the foil thickness (T) and the projectile size (D_p). We found that D_h, and other morphologic features such as rim structures in aluminum or spall phenomena in Teflon exhibit a systematic relationship to the target thickness. This relationship is described by polynomial fits which permit unique solutions for unknown projectile sizes (D_p) from the measurement of T and D_h on space-exposed surfaces.