A Simple Method for Calculating Sympathetic Detonation of cylindrical, cased explosive charges

Abstract Sympathetic detonation involves the propagation of detonation between individual explosive‐containing devices. When many such devices are stored together, the possibility of mass propagation exists. With mass propagation, the entire stored mass detonates nearly simultaneously. Such propagation is the most feared hazard of such explosive items in transportation and storage environments because of its potential for sudden extreme damage and loss of life. Safety requirements, including those for insensitive munitions, are best met if explosive devices can be designed to minimize the risk of sympathetic detonation. This paper presents a simple method for predicting the marginal conditions at which sympathetic detonation of cylindrical munitions just occurs (or just fails). The method can be easily and rapidly used in preliminary design studies to minimize subsequent hazard risks. It allows design and safety engineers to examine in minutes or hours what would take weeks or months of hydrocode calculations and months or years of field testing. The method involves algebraic solution of two‐dimensional shock propagation effects in an extension of Ferm and Ramsay's method for predicting shock initiation by spherical impactors (1) . The donor case expansion velocity is calculated using the well‐known Gurney formula for cylinders as amplified by Dehn (2) . The calculated initiation behavior of the acceptor charge(s) requires input data from wedge test results in the familiar Pop plot form, although a combination of card‐gap test data and failure diameter data can also be used (with reduced reliability) as a basis for estimating the Pop plot. The calculated results compare well with both hydrocode calculations and test data.