Cratering and Surface Waves Caused by Detonation of a Small Explosive Charge in Aluminum

摘要

Using the two-dimensional Lagrangian SHEP (Shock-Hydrodynamic-Elastic-Plastic) numerical technique, a calculation was made of the response of an aluminum block to the detonation of a small spherical explosive charge buried just below the surface. From the calculation, three waves are identified which produce upward velocities at the surface. The first two are the dilatational wave and the slower shear wave, which originate from the initial interaction of the explosive detonation with the aluminum. The third wave arrives later, propagating at shear wave speed. It appears to have its origin in the rebound of the bottom of the crater. The calculation is compared with results of a companion experiment (performed by Gulf General Atomic) in which surface motions were measured at various radial stations. The same three-wave structure was observed, but the measured wave amplitudes and the final crater dimensions were smaller than the calculated values. These discrepancies may be due to uncertainties in the energy content and the detonation characteristics of the small charge. (Author)