Analysis on ignition transient mechanical response of solid rocket motor grain under long-term storage

In order to analyze the ignition transient mechanical response of propellant grain under long-term storage, the linear viscoelastic material constitutive relationship of solid propellant was continued, and the ignition internal pressure and acceleration loads were applied to simulate the ignition transient process of solid rocket motor with finocyl grain. The mechanical response of propellant grain was obtained, and the mechanical properties of propellant grain before and after long-term storage were compared and analyzed. The results show that long-term storage has a significant effect on the mechanical properties of propellant grain. In the ignition transient state, stress concentration occurred at the front and rear wing slots of grain. After long-term storage, the displacement of the inner grain surface increases, and the displacement of the front and rear wings of grain increases even more. The connection between the front wing and the cylinder has the largest displacement and the most serious deformation, which is the weak part of grain. Due to the large increase in stress on the outer surface of grain at the front head, the possibility of debonding increases.