Journal of the Computational Structural Engineering Institute of Korea ISSN:1229-3059(Print) 2287-2302(Online) 한국전산구조공학회 논문집

This study proposes a numerical analysis method for evaluating the dynamic characteristics of a counter-rotating propeller (CRP) dual shaft system. The developed method employs a finite element formulation based on Timoshenko beam theory, incorporating gyroscopic coupling and bearing damping effects to derive the governing equations of motion. The proposed in-house computational code was verified through comparison with a reference co-axial rotor model, demonstrating excellent agreement in both natural frequencies and Campbell diagram trends, thereby validating the accuracy of the formulation. A parametric investigation revealed that increasing the inter-shaft bearing stiffness effectively rises the natural frequencies, thereby avoiding critical resonances within the operational speed range, whereas the influence of shaft diameter was relatively minor. The proposed numerical approach offers a reliable and efficient analytical tool for the design evaluation and vibration stability assessment of CRP dual shaft propulsion systems. Future work will focus on extending the model to account for nonlinear bearing characteristics and fluid–structure interaction effects to enhance its predictive capability under practical operating conditions.