Torsional Vibration and Sensitivity Analysis of Marine Propeller Shaft Using Hybrid Modeling

Abstract

This paper investigates the modeling of torsional vibration of marine shaft systems using the distributed-lumped (hybrid) modeling technique (DLMT). A new analytical method is employed to solve the equation of motion for the shaft torsional vibrations, and the solution is modeled as a series of interconnected distributed and lumped elements. The DLMT is then utilized to calculate the natural frequencies of a rotor system with various elements, and the results are compared and verified with the results of other techniques, such as the finite element method (FEM), using ANSYS software. A marine propeller shaft with multiple elements such as different couplings and flanges is then modeled and analyzed by the DLMT to obtain the natural frequencies. The results are compared and verified with the frequencies and mode shapes obtained by KissSoft software. In addition, the sensitivity analysis of significant parameters such as coupling stiffness, propeller moment of inertia, and shaft diameter are also implemented. The results show that the presented method can be simply and effectively applied to complicated systems, and brings highly accurate results.