Mechanical behavior of the Space Shuttle redesigned solid rocket motor (RSRM) propellant is studied from a phenomenological point of view. Motivated by the study of the experimental data three initially isotropic constitutive models have been developed. All models represent the effect of strain rate, superimposed hydrostatic pressure, and cyclic loading on the stress and dilatation response of the material. A particular emphasis is given to the prediction of volume dilatation. The model resulting in the best representation of the available data is calibrated using only a few tests. The predictions of the model are compared with experiments for several loading conditions not used in the calibration.

A three-dimensional stress analysis of a rocket motor under cyclic temperature loading was performed. The novelty of the analysis lies in the use of a propellant constitutive model that accounts for the effects of viscoelasticity, large deformation, temperature, pressure, and softening in monotonic and cyclic loadings. The material model was validated for the cyclic effects in terms of stress as well as dilatation responses. The role of various damage model parameters in the cyclic response was investigated. The distributions of these parameters were found to be consistent with the stress–strain field predictions of the rocket motor analysis, indicating efficiency and stability of the computational algorithm. It was concluded that the formulation and its implementation enables realistic stress analysis of solid rocket motors under general loading and environmental conditions, providing valuable information for their life assessment.