Dynamic modeling and structural dynamic analysis of a laminated casing system with bolted connections at both ends

Purpose The purpose of this study is to analyze the vibration behavior of a cylindrical shell model with bolted ends under different influence factors, and to provide a reliable theoretical prediction for the study of bolted casing. Design/methodology/approach Based on love theory, the vibration differential equation of laminated cylindrical shell is derived by using orthogonal polynomials as axial modal functions, combined with the boundary conditions of bolted joints and Lagrange equation, and the theoretical model of laminated cylindrical shell connected by bolts at both ends is established. By comparing the theoretical model with the finite element analysis results, the accuracy of the model established in this paper is verified. The influence of the number of bolts on the natural frequency and mode shape of the cylindrical shell and the influence of the axial, torsional, tangential and radial connection stiffness on the natural frequency of the cylindrical shell are analysed in detail. Findings The different number of bolts has a great influence on the natural frequency and mode shape of cylindrical shell. The axial connection stiffness, tangential connection stiffness and radial connection stiffness have significant effects on the natural frequency of cylindrical shells, while the torsional connection stiffness has little effect on the natural frequency. Originality/value The research content of this paper provides a key theoretical tool and prediction model for the safety design of aero-engine casing system. At the same time, the model established in this paper can be used as the theoretical basis of engine health management system (EHM), and an accurate vibration database under the health reference state is established according to the calculated natural frequency and vibration mode.