Abstract:

To facilitate the design of advanced aero-engine casings, a dynamic analysis framework is developed for the first time for the braided composite toroidal-cylindrical shell with soft coating (BCTCS-SC). The effective material parameters are first evaluated, after which high-order strain-displacement relations are established to describe the deformation of the coupled shell structure. The virtual spring method is adopted to model the rigid connection between the two infrastructures and the end constraints. The displacement fields are then approximated by doubly discrete spectral functions, and the governing dynamic equations are derived via the energy method. The proposed model is validated through comparative studies, and the corresponding mode shapes are visualized. Finally, the effects of key structural and material parameters on the natural characteristics, frequency splitting, and modal exchange are analyzed. The results further clarify the suppression effect of soft coating by modifying the equivalent stiffness and damping distribution. This study establishes a theoretical framework and a technical approach for frequency-splitting prediction and vibration-suppression design of coated braided composite coupled structures.

Key words: structural dynamics, advanced structure, vibration analysis, frequency splitting, soft coating, modal exchange