ANALYTICAL MODELING OF A SINGLE- AND A MULTI-STAGE RAPID GROUND PENETRATOR IN NORMAL AND IN OBLIQUE IMPACT

摘要

Rapid ground penetrators are becoming popular tools for exploring the Moon and Mars. They are cost-effective and enable placement of scientific instruments at the surface and subsurface of select locations. A simplified analytical method of predicting the performance of rapid ground penetrators in normal and in oblique impact is presented here. The analytical solution assumes that the penetrator nose causes a cavity expansion of soil disks as it is advanced perpendicularly through the center of the disks. The oblique impact model is also based on kinematics and assumes that the lateral movement of the penetrator is resisted by the soil's plastic stress. A new soil-locking model is used. The analytical method has been written into a PC-based computer program that is called GRDPEN. Presented herein are also predictions of the performance of a single- and a multi-stage penetrator in normal and in oblique impact at various impact velocities. The method was also used to predict the performance and stress levels of penetrators with different nose shapes.