Vibrations of Misaligned Rotor System with Hysteretic Friction Arising from Driveshaft–Stator Contact under Dispersed Viscous Fluid Influences

Dynamic analysis of a combination of misaligned rotors, the disturbance of the Cardan joint and the rotor–stator rubbing within a restricted clearance space in a viscous fluid is complex and can result in persistent vibration anomalies that are often misunderstood. It becomes increasingly important to gain some insights into how the transmission of coupled motion responds dynamically under a variety of conditions. This paper introduces an efficient simulation of the misaligned multi-degree-of-freedom rotor’s model, which was developed to predict the transient dynamic behaviours of a driveshaft deflection. The model accounts for tight clearance as a function of contact deformation according to nonlinear Hertzian contact theory. The paper also examines recent research by considering the influence of parameters such as eccentric masses, applied torques and flexible coupling joint perturbation introduced in the proposed rotor system. The simulation results indicated that the viscous fluid surrounding the driveshaft had sufficient torsional flexibility to dampen the rubbing impact to the driven shaft displacement. In addition, the torsional fluctuations of the flexible coupling abruptly increased, and then significantly impacted the vibration of the submerged driveshaft. Parametric studies involving the interconnected rotor models indicated that the effects of fluid on a close-bounds contact area can create partial disturbance reduction. The high rubbing contact is shown to be lost through the Hooke’s joints during power transmission. The speed-frequency spectrum maps provide valuable information on all the modelled excitations over the frequency of the twice-running speed resonance in a viscous medium. Further, nonlinear characteristics are reconstructed through orbit shapes and can be adopted in the condition monitoring of rotors in engineering practice.

Nonlinear numerical and experimental study on the second-order torsional and lateral vibration of driveline system connected by cardan joint

In this article, a nonlinear dynamic model with five degrees-of-freedom for a four-wheel-drive vehicle driveline connected by a cardan joint, including dynamic intersection angle, nonconstant velocity, and additional moment caused by the cardan joint, is established by using the Lagrange method to analyze the driveline coupling vibration in both torsional and lateral directions. High-order Runge–Kutta algorithm is applied to solve the differential equations and to calculate transient responses of the driveline rotors under acceleration condition. The color maps and second-order vibration of the driveline are acquired by frequency spectrum analysis and order tracking analysis, respectively. The second-order vibration and noise of the driveline and vehicle interior caused by the cardan joint is validated by vehicle experimental results and reduced effectively by decreasing intersection angle of the cardan joint under the operational condition. Moreover, application of a flexible coupling instead of the cardan joint significantly reduces the second-order vibration but simultaneously generates low-level third-order vibration.

Transmission with Cardan Joint Parametre Influence to Centrifugal Pump Characteristics

Transmission with cardan joints and non­linear gearbox elements generates vibrations caused by spinning motion of transmission. This affects the pressure and productivity of centrifugal pump. The momentum of centrifugal pump in turn affects dynamic characteristics of transmission. In order to find the effect of transmission elements on centrifugal pump we investigate transmission composed of asynchronous electrical engine, gear box, cardan joint and Ziegler Ultra centrifugal pump. We create mathematical models of transmission and centrifugal pumps and investigate how the dynamic effects of transmission influence productivity centrifugal pump. This model can be applied to study the transmission parameters, effect of intake and outflow parameters on productivity of centrifugal pump and presence of cavitation. The paper includes results and conclusions of mathematical model.