Impact cratering has a number of important scientific, military, and civilian applications. In this study, the techniques of quarter space penetration, transparent soil modeling, and high-speed photography are combined to visualize impact cratering of spherical projectiles as they penetrate into different granular media. The shape and size of the cross section of the impact crater were visualized and quantified using these techniques for two granular materials, in both dry and saturated conditions. The crater rate of expansion and the velocity decay were also mapped and used to estimate deceleration rates of the crater expansion. A tool is presented for assessing the shape and size of the crater for the case when the penetrator diverges from the observation window. Shallower craters were observed in angular fused quartz targets in comparison to the rounded sand targets. Similarly, higher viscosity saturating fluids lead to narrower cavities. Besides the open cavity, permanent dilation regions ahead of the projectile were also mapped. The evolution of the crater versus time was used to estimate the deceleration of the rate of expansion of the crater. New Poncelet parameters are also developed for specific testing conditions not available in the literature.

撞击坑有许多重要的科学、军事和民用应用。在这项研究中，将四分之一空间穿透、透明土壤建模和高速摄影技术相结合，将球形弹丸穿透不同颗粒介质时的撞击坑可视化。在干燥和饱和条件下，使用这些技术对两种颗粒材料的撞击坑横截面的形状和大小进行了可视化和量化。火山口的膨胀率和速度衰减也被绘制出来并用于估计火山口膨胀的减速率。当穿透器从观察窗口发散时，提供了一种用于评估陨石坑形状和大小的工具。与圆形砂目标相比，在角状熔融石英目标中观察到更浅的陨石坑。类似地，更高粘度的饱和流体导致更窄的腔。除了开放的空腔外，还绘制了射弹前方的永久膨胀区域。火山口随时间的演变被用来估计火山口膨胀速度的减慢。还针对文献中未提供的特定测试条件开发了新的 Poncelet 参数。