Vibration analysis of a rotor supported on magnetorheological squeeze film damper with short bearing approximation: A contrast between short and long bearing approximations

Abstract

Squeeze film dampers are widely used to reduce the vibration of rotating systems. Using magnetorheological fluid in these dampers can lead to a variable-damping damper called Magnetorheological Squeeze Film Damper (MRSFD). Magnetorheological fluid viscosity alter under different values of magnetic field. The previous research have widely used long bearing approximation to derive the equations governing the hydrodynamic behavior of MRSFDs. In this paper, the behavior of MRSFDs has been studied using short bearing approximation. Next, the effects of MRSFDs on the dynamic behavior of a flexible rotor have been studied, using finite element method (FEM). Synchronous whirl motion has not been imposed on the system behavior, as an external assumption. Damper pressure distribution and forces, dynamic trajectories, eccentricity and the frequency response of the rotor are tools used to analyze the dynamic behavior of MRSFDs and rotor system. As the results show, it seems to be more precise to use short bearing approximation to analyze dampers with aspect ratios lower than a limit (especially L/D < 1). Furthermore, by controlling electrical current one can control the dynamic behavior of a rotor, to avoid failure and damage. Finally, the whirl motion of the rotor was observed to remain synchronous, even when fluid forces are present.

Non‐Settling Super‐Strong Magnetorheological Fluids

“…[1,4] If the strength and stability of MR fluids can be dramatically improved at the same time, MR fluids can revolutionize certain industries. [8][9][10][11][12][13][14][15][16][17] Another thing to note is that the generated MR fluid is particularly useful when operating at moderate magnetic field strengths inside the MR device. [6,39] When a strong magnetic field is required, a heavy and bulky electromagnet should be used, thereby making the MR device itself heavy and bulky.…”

“…It is expected to be a turning point that can widely apply MR fluids to a wider range of industrial fields as well as large structure dampers for buildings and bridges. [7][8][9][10][11][12][13][14][15][16][17] We also proposed a simple constitutive equation that expresses the yield stress as a function of volume fraction and compared it with the experimental values to predict the yield stress when a specific volume of magnetic particles is used. This constitutive equation can be applied without special conditions to any complex system exhibiting yield stress.…”

“…[6,7] Because of the responsive and tunable nature of these unique rheological properties, MR fluids are used in various devices that require fluid flow control, such as rotor dampers, power steering pumps, shock absorbers DOI: 10.1002/smll.202300320 for motorcycles and automobiles, and haptic devices. [8][9][10][11][12] They are also used to protect large structures, such as large buildings and bridges, against external impacts such as earthquakes and wind gusts. [13][14][15][16] Although MR fluids have strong potential for use in numerous industrial applications, their practical implementation is hindered by their poor long-term stability.…”

Study on the Vibration Mitigation Characteristic of Dual Clearance Squeeze Film Damper

“…Jiyan Wang built the rotor-SFD-Sling bearing system and analyzed the characteristics from periodic whirling to chaos based on the Runge-Kutta method [14]. Mostafa and Abdolreza Ohadi Irannejad investigated the dynamic characteristic of a rotor supported on a novel SFD: MHSFD, and Mostafa Irannejad concluded that the rotor could avoid to be destroyed by controlling the electric current [15]. Geraldo Creci and Jose Orlando Balastrero did a research to obtain the optimum SFD clearance by analyzing the transient response of the rotor-SFD system [16].…”

Parameter optimization design of rotor dynamic vibration absorber

“…Late online automatic balancing technology, which mainly takes the form of applying recreation forces on the rotor structure, often uses the following methods: (a) For balancing the system, to apply real-time recreation forces to the rotor system by using controllable electromagnetic bearings [9][10][11]. (b) To apply a real-time variable damping force to the system by using controlled magnetorheological fluid damper [12][13][14][15]. However, the precipitation problem of magnetorheological fluids affects long-term use.…”