The Initiation of Explosive Charges by Rapid Shear

Abstract : Friction and/or shear have been suggested by many people as possible sources of ignition in solid explosives. Although these two mechanisms are usually considered to be distinct, on a microscopic scale they are essentially the same. On a macroscopic scale, friction involves sliding interfaces and is described in terms of the coefficient of friction and the stress normal to the interface. The rate of heat generation at the surface is the product of the sliding velocity times the coefficient of friction times the normal stress. On a microscopic level, friction is caused by surface irregularities (asperities) which deform as the surfaces slide. The frictional heating is caused by viscoplastic work on the asperities. In this paper, I will consider the conditions required for ignition as the result of shear deformation and viscoplastic heating.