Analysis of Linear Shaped Charge Igniting Rapid Deflagration Cord using Explicit Dynamics Method

Abstract

An ordnance device typically is composed of several components that are initiated sequentially. Reliability of this initiation train is critical to its performance. This paper describes the testing and analysis methods used to understand the mechanisms involved and to achieve a high reliability. The scope of this paper begins with the output of the linear shaped charge (LSC) creating a stimulus received by the rapid deflagration cord (RDC) pickup charge. This stimulus travels through a narrow channel and makes several turns before impacting the target. The degree of confinement can vary significantly during the event due to perforation of the housing by the LSC jet. In order to understand this complex and dynamic event, a 3-dimensional Explicit Dynamics analysis is used to study the gases/condensates flow and pressure exerted onto the target under various design configurations. Explicit Dynamics is a Finite Element Analysis method that integrates the time of all meshes at stable time steps and ensures solutions representative to the real time behavior. Computational results describe the LSC function and interaction of its reaction products and liner material with the RDC end-tip. Results of the ignition gap test are presented and discussed in this paper. This approach enabled PSEMC to understand the mechanism of the event and improve the design based on knowledge acquired through these analyses.