Structural Analyses of Solid Propellant Grains under Ignition Pressurization using Explicit Dynamics Method

摘要

A 3-dimensional structural analysis of propellant grains in a gas generator during its ignition event using explicit dynamic method was conducted in this study. This innovative approach enabled the author to reproduce the failure modes and understand the system failure in detail. Explicit Dynamics method integrates the time of all meshes at every time step (explicit) and the time step is controlled by the speed of sound traveling through the structural materials ensuring solutions representative to the real time behavior (dynamics). Largangian/ Eulerian coupled meshes are utilized to solve the behaviors and interactions of solid (propellant grains assembly by Lagrange) and fluid (gaseous combustion products from igniter by Euler) parts. This method computes the transient pressure loading representative to device geometry directly and not in need of making major assumption of stress loading conditions while performing the analysis. Results of pressure measurements at various locations inside gas generators for the model validations are also reported in this paper.