Abstract
As crater size decreases, the fraction of material ejected by spallation increases. From our previous experiments, the change of crater volume owing to the change of spallation was seen (Hiraoka et al., 2004). It is of importance to understand on which physical properties of the targets, the spallation process depends. In this study, we focus on the crater depth-diameter ratio as the empirical index of the crater morphology and the strength as the dominant factor among the physical properties of the target. We perform impact experiments for targets with different strength, using a powder gun at Kobe University. The mortar, a mixture of cement, sand, and water in a ratio 1:1:0.47, that has different strength according to different curing environment is used as the target. Cylindrical projectiles (aluminum with magnet, 15mm in diameter, 10mm in height and about 9.5g in weight) are accelerated to about 650m/s. The target compressive strength is measured by uniaxial compression test and the tensile strength is estimated by Brazilian test. We will report on the relation between the crater depth-diameter ratio and the target strength.
