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

Abstract

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.

A Comprehensive Study of Cardon Shaft Using Modal Analysis

“…Transmission shafts are a common component of both vehicles and locomotives. If it can be done without increasing costs or sacrificing quality and dependability, reducing the weight of the Cardan (drive) shaft can play a part in the overall weight reduction of the vehicle [23]. Using different stacking sequences, it is feasible to create a modified Cardan shaft with reduced weight, increase the shaft's natural frequency, and reduce bending stresses.…”

Dynamic Analysis of a Rotating Cardan Shaft under the Influence of a Breathing Crack and Dense Fluid Force

“…where μ that depends on θ 1 and ψ 1 is a small perturbation parameter modelled on the basis of Hooke's joint kinematics and expressed in detail in [23] and…”

“…In the current work, a model for analyzing the high vibrations of a Cardan shaft focusing on coupling malfunctions and extracting the features of a cracked driveshaft system coupled to a single Hooke's joint in a viscous fluid is developed. Earlier works [16,[20][21][22][23] have shown that resistance fluid has a significant impact on rotor system behaviour, and the wavelet technique is an effective signal processing tool for crack detection, which will be used here for crack feature extraction in a fluid medium. e use of the rotating reference frame will assist in a better understanding of the nature of the shaft whirl and facilitate the shaft modelling and the fluid-driveshaft coupling.…”

Bursting Oscillation Mechanisms of a Desktop Medical Shaker with Eccentric Turntables Affected by Dry Friction

“…Many valuable studies [6][7][8] have been conducted on the application of eccentric shafts in existing literature, but this does not mean that the eccentric shaft is perfect. Actually, in its practical applications, the mechanical failure [9][10][11] has widely found that the actual speed of a desktop shaker intermittently exceeds the set speed after prolonged use, which corresponds to busting oscillations [12][13][14] in the rotor-oscillator system and can be named overspeed oscillation. Diferent from other current research work focusing on the application of eccentric shaft technology, the main task of this paper is to study defects, causes, and solutions of it.…”