Impact cratering experiments were performed on semi-infinite concrete targets with 7 mm-diameter 40CrNiMo steel long-rod projectiles at impact velocities ranging from 2117 m/s to 3086 m/s by using a two-stage combustion light-gas gun. After the impact experiments, the crater diameter and depth as well as the crater volume were carefully measured. The concrete fragments were collected from the target chamber and the fragment mass was measured. The size of the crater (including the volume, diameter, and depth) and the fragment mass increased with increasing impact velocities, while the fragment distributions at different impact velocities were almost the same. Scaling laws for the crater volume impacted by the rod-shaped projectile were discussed and an empirical formula of crater volume was determined by the experimental data from the literature. Through the verification of the present experimental results, the predictive ability of the empirical formula proved to be reliable. Scaling laws for the size distribution of concrete fragments were also discussed. The normalized fragment mass distribution was proportional to the impact velocity raised to the power 1.5.

中文翻译：

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不同长径比弹丸半无限长混凝土靶上的超高速撞击坑

使用两级燃烧轻气枪对半无限混凝土目标进行撞击坑实验，使用直径为 7 mm 的 40CrNiMo 钢长杆弹丸，冲击速度范围为 2117 m/s 至 3086 m/s。撞击实验后，仔细测量了陨石坑的直径和深度以及陨石坑的体积。从目标室收集混凝土碎片并测量碎片质量。陨石坑的大小（包括体积、直径和深度）和碎片质量随着撞击速度的增加而增加，而不同撞击速度下的碎片分布几乎相同。讨论了棒状弹丸撞击弹坑体积的标度规律，并根据文献中的实验数据确定了弹坑体积的经验公式。通过对现有实验结果的验证，证明了经验公式的预测能力是可靠的。还讨论了混凝土碎片尺寸分布的比例法则。归一化碎片质量分布与冲击速度的 1.5 次方成正比。