Thermomechanical response studies of solid propellants subjected to cyclic and random loading.

Abstract

An analytical and experimental study of the interaction between heating and dynamic response of solid propellants is presented. Emphasis is placed on the evaluation of linear viscoelastic theory in predicting thermomechanical behavior and also on the nature of the interaction between displacement, stress, and temperature response. For analytical and experimental simplicity, the investigation deals with a specimen that is loaded in simple shear and insulated such that heat flow is restricted to occur normal to the direction of shear. Two types of loading are considered: constant displacement amplitude and inertial driving by means of an attached mass. The response to both harmonic and stationary random loading processes is determined analytically, and it is shown for both cases that large temperature increases may occur in the specimen with attached mass because of thermal instabilities. Good agreement between experiment and theory was obtained over most of the range of strain and frequency, but some stress-strain nonlinearity and gradual propellant degradation were observed.