Vibration Characteristics and Local Slope Distributions of Multi-Segment Shells

Abstract

In light of the increasing demand for rocket vibration analysis and the limitations associated with traditional methods, this study proposes a novel approach that helps to address these challenges. It specifically examines the vibration characteristics and local slopes of rocket fuselage during the pre- and post-stage separations. A semi-analytical dynamic theoretical model has been developed based on a simplified multi-segment shell framework. This model allows for the determination of natural frequencies, vibration modes, and slope distributions of the multi-segment shell structure, with the effectiveness of the model validated through numerical examples. The research further investigates the influence of material and geometric parameters on the rocket fuselage's performance. Variations in material composition, half-top angle, and thickness each have distinct effects on vibration characteristics. Additionally, a comparative analysis of pre- and post-stage rockets reveals that while the fundamental frequencies of both structures are similar initially, the post-separation rocket fuselage exhibits higher frequencies at higher orders. Notably, for the booster substructure, post-separation results in a flattening of local torsional curvature and the release of bending energy. Overall, this research provides valuable theoretical support for the optimization of rocket fuselage, vibration control, and safety assessments during separation.