Analysis of Explosively Actuated Valves

Abstract

Explosive valves are generally composed of a plunger which is explosively driven along the bore of a cylindrical housing. The plunger is forced to stop at a location designed to alter a particular fluid flow configuration. The stopping point of the plunger is determined by the drag forces between the plunger and the housing and is the critical factor in obtaining the desired flow. One way of calculating these drag forces is to model the valve as a series of thin disks and to assume an elastic interference fit between the disks of the plunger and the disks of the housing. Explosive valves constructed with new materials and new geometries, however, have made it necessary to account for plastic deformations, including strain hardening. This paper introduces an elastic-plastic disk model based on a combination of closed form and finite element results. The behavior of the calculations with elastic-plastic materials is compared to various finite element representations of an explosive valve to verify the disk model and to quantify the effects of plasticity and large deformations. Finally, the elastic-plastic calculations are compared to experimental results obtained from actual valves with various materials and geometries.