Mechanical Performance Evaluation and Life Prediction of Vertical Storage Solid Rocket Motor Grain

ABSTRACT Aiming at the aging problem of vertical storage solid rocket motor (SRM) grain, the influence of load on the initial modulus and maximum elongation of HTPB propellant during the aging process was systematically investigated through thermomechanical coupled accelerated aging test and numerical simulation. The test results show that the tensile state aggravates the aging process of the propellant. The compression state effectively inhibits the aging process. Subsequently, an aging model considering the effect of load was constructed based on the Arrhenius equation. The model was embedded in the simulation calculation through the secondary development of the Abaqus subroutine, which characterized the non‐uniform distribution of the mechanical properties of the grain during long‐term vertical storage. When the maximum elongation of the material is reduced by 50% as the failure criterion, the failure area of the grain gradually expands downward from the upper tensile part over time, and finally completely fails after 16 years of storage. The quantitative evaluation method established in this study realizes the prediction of the distribution law and evolution process of the mechanical properties of the long‐term vertical storage SRM grain, which can provide theoretical support for the structural integrity analysis and service life prediction of the SRM.