Structural Integrity Analyses on the Anti-high Overload of a Solid Rocket Motor

Solid propellant works as the most key component for solid rocket motors, and its mechanical behaviors paly a dominant role in the structural integrity of the motor. As typical viscoelastic material, it presents a strong rate-dependence, which would affect the integrity behavior. In the present work, a solid propellant was performed for its constitutive behaviors under wide strain rate loading from 30 to 3000 s−1 using the developed split Hopkinson bar apparatus. A linear viscoelastic constitutive model was then established for carrying out the finite element analysis of an engine structure. As indicated from the simulation results, the possible failure zones in solid rocket motor are revealed, and some stress concentrations localizes in its middle and rear section of the coating layer. Grain failures tend to occur in the concave turning points between the grain rear end and the cushion. The effect of high overload was also analyzed under various cushions, and it was also found that the cushions facilitate the integrity by absorbing energy and confining the deformation of the grain.