Effect of the shear area on the probability of an explosion of high explosives under shock-induced shear

The applied pressure resulting in an explosion in the case of shock-induced shear is demonstrated to depend on the shear area [area of the contact of the high explosive (HE) with the metal surface]. The dependence of the probability of an explosion of the HE (phlegmatized HMX and PETN) compressed between two steel plates (end faces of two rollers) on the applied pressure and the contact area of the HE with the upper roller is confirmed in experiments on sensitivity to friction under shock-induced shear. The upper roller is shifted by 1.5 mm. It is demonstrated that an increase in the area of the shock-pressed HE contact with the roller increases the probability of the HE explosion under shock-induced shear of the upper roller at identical pressures applied to the HE. A scale factor of the influence of the HE/roller surface contact area on the pressure at which the HE explosion occurs under shock-induced shear of the surface contacting the HE is found. It is shown by statistical methods that the pressure leading to the HE explosion under shock-induced shear of the adjacent steel surface with respect to the HE is distributed in accordance with Weibull's two-parameter law.