Repeated loading damage analysis of thin-walled composite shell for lighter structural design

The composite shell is one of the crucial components of solid rocket motors. Its design goal is to reduce the shell mass as much as possible while ensuring technical and cost requirements. This paper proposes a damage analysis method for the thin-walled composite shell secondary loading process based on a refined finite element model to verify the damage caused by the thin-walled composite shell secondary loading process and the performance decline of the shell and to assist in the lightweight design of the thin-walled composite shell. The shell's damage failure state and crack propagation path are analyzed by establishing the acceptable finite element model and introducing the damage failure criterion and the stiffness degradation model. Based on the model, the damage state of the shell during the secondary loading process is described, and it is determined that the re-loading has little effect on the blasting performance of the shell. For composite shells used in small quantities, the effects of damage due to initial loading can be of no concern during design. This method can provide a theoretical basis for thin-walled composite shell safety factor selection and damage state assessment to achieve the thin-walled composite shell lightweight design goal.