Solid propellant Mechanical Behavior Studies. Volume I. Effect of Grain End Shape on Stress Concentrations at the Case-Propellant Interface

Abstract

Abstract : This report presents the results of an experimental program to evaluate the effects of grain end termination geometry on the failure of case-bonded solid propellant motors subjected to decreasing temperature. In addition to the end termination study, several phases of the overall program were devoted to a study of the applicability of reaction rate theory as a means of characterizing the failure and cumulative damage behavior of solid propellants. These results are reported in Volume II of this report. The experimental end termination program was divided into three phases. The initial phase was devoted to a continuation of a photoelastic study from an earlier program. In this study, many different grain end geometries were evaluated to determine stress concentrations at the propellant-case termination interface. In Phase II, several of these end configurations were subsequently evaluated in a series of PBAN propellant analogue motors subjected to monatomically decreasing and cyclic temperatures. Based on these results, the best of the shapes studied was incorporated into a 12-inch diameter demonstration motor during Phase III. (Author)