On the Pressure Estimation in Impact Sensitivity Experiments on Explosives and the Problem of Initiation

摘要

Pressures generated on the explosive layer under conditions of experiments on the impact sensitivity of explosives have been calculated making use of the basic assumptions embodied in the Hertz theory of impact, taking data from certain experiments on explosion. In the absence of any knowledge of the elastic constants of explosives under dynamic conditions of loading, calculations have been made for two sets of elastic constants, one for steel to steel impact and the other for steel to a solid having elastic constants onehyphen;tenth that of steel. The experimental pressures lie between these two values. A reinterpretation of the results leads to a relation between a massmand its height ofhfor fifty percent explosion efficiency. The conduction at the solid air interface due to an entrapped gas bubble compressed by these pressures has been considered. The amount of the explosive heated to the optimum temperature required for explosion, within times comparable to impact explosion delays, has been shown to be of the order of the hot spot size found from other considerations. The variation of the heighthand the pressurepof the gas surrounding the explosive layer for fifty percent efficiency is shown to be governed by the relationh/p2= constant.