基于随机本构模型的HTPB推进剂装药结构完整性评估

Aiming at the dispersion of the mechanical properties of HTPB propellant， the random parameter described by the lognormal probability density function were introduced， and the random constitutive model was constructed. The structural integrity analysis of the solid rocket motor grain under the ignition pressurization condition based on the random constitutive model was carried out. The results show that the five groups of stress-strain curves predicted by the random constitutive model have a high coincidence degree with the five groups of stress-strain curves of the test， and the test curves all fall within the 95% probability interval. The random constitutive model can better reflect the dispersion of propellant materials. The mechanical response of the grain is related to the random parameter. The maximum Von Mises stress， maximum Von Mises strain， maximum displacement， maximum damage index and safety factor are approximately linear with the random parameter. The error of the mechanical response of the grain obtained by the constitutive model based on the experimental curve fitting and the random constitutive model based on the probability interval prediction does not exceed 1%. The random constitutive model based on the probability interval prediction can accurately predict the mechanical response of the grain under the ignition pressurization load.