Reliability Calculation of Solid Propellant Based on Accelerated Degradation Test

With the improvement of solid propellant reliability, the collection of failure data of test is facing severe challenges. In view of the difficulty in evaluating the reliability of solid propellant, a method for calculating the reliability of solid propellant based on accelerated degradation test is proposed. Firstly, according to the performance degradation data of solid propellant, the performance degradation models with multiple groups of samples under multiple accelerated stress levels are determined by linear regression method. Combined with the failure threshold, multiple pseudo lifetimes at each accelerated stress level are obtained. Then the pseudo-life distributions under different accelerating stress levels are tested. Finally, the maximum likelihood estimation method is used to estimate parameters of accelerated model, and the reliability function of solid propellant storage life is derived. The example shows that the reliability of a solid propellant stored at an alternating environment with the low temperature $15{\circ}\mathrm{C}$ and the high temperature $25{\circ}\mathrm{C}$ for 18 years is 0.9027. It shows that the reliability of solid propellant under an arbitrary stress level can be evaluated by the accelerated degradation test data.