砂中高速貫入時の物体挙動に砂の形状パラメータが与える影響

抄録

Powder such as sand show different properties from both solid and liquid, and its behavior is difficult to understand due to their nonuniformity. Research about sand has been actively conducted in recent years. If the projectile penetrates into the sand at high speed, complex phenomena can't be seen at low speed, and they are very interesting. Previous studies confirmed that the packing density of sand greatly contributes to the penetration behavior of the projectiles. However, the influence by parameters other than packing density is still unknown. In the static penetration test, it is known that the shape of the particle influences the behavior of the penetrating object. Therefore, in this study, to verify the influence of sand particle shape on projectile behavior at high speed penetration, the particle shape of two types of sand, which are different in shape, was quantified. To evaluate the particle shape quantitatively, use the coefficient of form unevenness. In order to calculate the coefficient of form unevenness, the projected area of sand particles and the perimeter of the particles were measured using a digital microscope. The influence of the shape of sand particles on the behavior of the projectile at high speed penetration was investigated.