A modified dynamic model of rotor systems with spline coupling considering misalignment

This paper presents a modified modeling method for rotor systems connected by spline coupling. The new approach divides the spline coupling into multiple elements, and the nonlinear meshing forces of each element are directly incorporated into the system's dynamic model rather than being simplified into analytical stiffness, thus avoiding additional calculations and making the spline coupling model more refined. Based on the established dynamic model of the rotor system connected by spline coupling, the study investigates the system's amplitude-frequency characteristics, rotor orbits, and time histories, as well as the effects of rotational speed on meshing forces across the meshing teeth of the spline coupling's elements. Additionally, the study considers both parallel and angular misalignments of the spline coupling, examining their impact on the rotor system's dynamic characteristics and the meshing forces on the coupling's elements. The results indicate that misalignment increases the system's vibration amplitude and the maximum meshing force of the spline coupling, with angular misalignment causing a significantly uneven distribution of meshing forces along the axial direction of the spline coupling. Moreover, misalignment reduces the meshing clearance between the internal and external teeth of the spline coupling at critical speed, decreasing the maximum meshing force. The modified model proposed in this paper can be widely used to analyze the dynamic characteristics of the rotor system connected by spline coupling.