Study on the Effect Mechanism of MRD to Rotor System

Abstract

Magnetorheological damper (MRD), a semi-active control device, has the stability of the passive control device and the adaptive ability of the active control device. It is considered to be an ideal replacement for the squeeze film damper (SFD) and has been extensively investigated. However, the effect mechanism of MRD to a rotor system is still unclear, which will influence the structural design and control strategy of MRD. This paper aims to propose a general MRD excitation model for a rotor system and discover the effect mechanism. First, the effects of current and eccentricity on mechanical properties of MRD are studied in detail and approaches suppressing the vibration amplitude of a rotor system are put forward. Then, a general model considering MRD, ball bearing and squirrel cage is proposed. Based on the finite element method, the dynamic equations of a rotor-bearing-squirrel cage system with MRD and mass imbalance are presented. Finally, the influences of MRD on the dynamic characteristics of the rotor system are investigated, and the effect mechanism is discovered. In addition, the nonlinearity which is not desirable as it causes fluctuating stresses in the main components of the rotor system and eventually leads to their failure due to fatigue, are observed. The changes of damping and stiffness of MRD can alter the damping performance of MRD and the suitable range of current forms the zone of effective damping, which lays helpful guidance for the design and application of the MRD.

Investigations of Sustainable Biodegradable Oil and Magnetic Particle‐Based Magnetorheological Fluid Dampers for Vibration Attenuation of a Rotor Dynamic System

“…[ 56 ] This effect leads to an increase in base vibration amplitude with the increase in current supply. [ 57 ] The tendency of the clumping effect is observed at near resonance after 0.6 A for Sample 2, as shown in Figure . The results were obtained by testing the vibration attenuations at various currents for MRF sample using the experimental setup, which shows the negative damping effect at a higher current (i.e., clumping effect when vibration amplitude starts to increase).…”

“…Both the results of Sample 2 and Sample 5 are inline with the result of Wang et al 2019. [ 57 ] Therefore, more possibility of vibration amplitude reduction with an increase in current supply may be experienced in Sample 5 rather than in biodegradable oil‐based MRF Samples.…”

The Dynamic Characteristic of a Faulted Rotor System with Multi-Objective Optimization Designed SFD

“…Considering the effect of the cavitation, Ruggiero et al [4] found the "oil whirl" produced by the non-linear fluid forces. Wang [5] studied a controllable SFD for a rotor system and revealed its effect mechanism. Chang [6][7][8] analyzed the dynamic behavior of a hybrid SFD-mounted gear-bearing system based on the typical unbalance approximation and discussed the rotating speed and damping effects.…”

Study on the vibration control method of a turboshaft engine rotor based on piezoelectric squeeze film damper oil film clearance

“…Chasalevris and Dohnal (2014) proposed a passive adjustable sliding bearing, which can effectively reduce the resonance amplitude of the journal, but the damping frequency band is limited, and most of them are suitable for high-frequency vibration. In terms of designing various dampers (Lu et al, 2019), Forte et al (2004), Wang et al (2019) and Piccirillo et al (2015) studied the vibration reduction effect and strategy of a Mr Fluid damper in a rotor system. Zhu (2001) proposed the magnetorheological fluid SFD that changes the flow form of a magnetic fluid by applying a controllable magnetic field in the oil film region so as to control the dynamic characteristics of the damper and effectively control the overcritical vibration of the rotor.…”