The dynamic characteristics of a rotor supported on ball bearings with different floating ring squeeze film dampers

2014 ◽  
Vol 80 ◽  
pp. 200-213 ◽  
Author(s):  
Hai-lun Zhou ◽  
Guo-quan Feng ◽  
Gui-huo Luo ◽  
Yan-ting Ai ◽  
Dan Sun
Keyword(s):  
Dynamic Characteristics ◽  
Squeeze Film ◽  
Ball Bearings ◽  
Squeeze Film Dampers

scholarly journals Dynamic Behavior Analysis of Intermediate Bearing-Squeeze Film Dampers-Rotor System under Constant Maneuvering Overload

2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Nan Zheng ◽  
Mo-li Chen ◽  
Gui-Huo Luo ◽  
Zhi-Feng Ye
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Characteristics ◽  
Rotor System ◽  
Squeeze Film ◽  
Nonlinear Dynamic Model ◽  
Maneuvering Flight ◽  
Squeeze Film Dampers ◽  
Frequency Components ◽  
Simulation Results ◽  
Rotor Dynamic

Under the flight maneuvering of an aircraft, the maneuvering load on the rotor is generated, which may induce the change of dynamic behavior of aeroengine rotor system. To study the influence on the rotor dynamic behavior of constant maneuvering overload, a nonlinear dynamic model of bearing-rotor system under arbitrary maneuver flight conditions is presented by finite element method. The numerical integral method is used to investigate the dynamic characteristics of the rotor model under constant maneuvering overload, and the simulation results are verified by experimental works. Based on this, the dynamic characteristics of a complex intermediate bearing-squeeze film dampers- (SFD-) rotor system during maneuvering flight are analyzed. The simulation results indicate that the subharmonic components are amplified under constant maneuvering overload. The amplitude of the combined frequency components induced by the coupling of the inner and outer rotors is weakened. The static displacements of the rotor caused by the additional excitation force are observed. Besides, the period stability of the movement of the rotor deteriorates during maneuver flight. The design of counterrotation of the inner and outer rotors can effectively reduce the amplitude of subharmonic under constant maneuvering overload.

Double Nonlinearity–Unbalance Response of Rotor on Ball Bearings With Squeeze Film Dampers

2011 ◽  
Author(s):  
David P. Fleming
Keyword(s):  
Public Information ◽  
Nonlinear Behavior ◽  
Maximum Load ◽  
Squeeze Film ◽  
Ball Bearings ◽  
Rolling Element Bearings ◽  
Rotating Systems ◽  
Squeeze Film Dampers ◽  
Rolling Element ◽  
Design Guidance

The nonlinear behavior of rolling-element bearings and squeeze-film dampers is well recognized; stiffness coefficients (and for dampers, damping coefficients also) increase as vibration amplitude increases. In the design of rotating systems using these elements, nonlinear aspects must be accounted for, and support properties chosen to handle the specific imbalance expected. Rolling-element bearings (e.g., ball bearings) are often used in combination with squeeze-film dampers (SFD). However, there seems to be no public information on the interaction of these two nonlinear elements. The purpose of this paper is to analytically document this interaction, and provide design guidance to optimize system performance for normal and extraordinary imbalance levels. Results show that a well-designed SFD in conjunction with a ball bearing performs similar to an optimized linear support with linear bearing, but care must be taken to ensure that the SFD can handle the maximum load encountered.

Determination of Damping Coefficient of a Bump Foil Squeeze Film Damper

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
G. Saravanakumar ◽  
L. Ravikumar ◽  
R. Yogaraju ◽  
C. Shravankumar ◽  
V. Arunkumar
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Research Work ◽  
Squeeze Film ◽  
Jet Engines ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Magneto Rheological ◽  
Temperature Dynamic

The present investigation is aiming to get better squeeze film dampers which are normally used in high speed jet engines to minimize small amplitude large force vibrations. The investigation was started with squeeze film dampers employing conventional lubricating oils. Magneto rheological fluids are then used to enhance the viscosity characteristics of the fluid under the influence of magnetic fields in order to improve the damper performances. It is observed that the dynamic characteristics of the damper with magneto rheological fluids are enhanced. Further to improve the damper performance, few modifications in the damper assembly are carried out in this research work. A good amount of reduction in the amplitude of vibrations is observed in these modified squeeze film dampers coupled with magneto rheological fluids. This research work discusses dual and triple clearance squeeze film dampers and bump foil squeeze film damper, also subjected to variation in temperature. Dynamic characteristics are found to be decreasing as the viscosity of the fluid decreases with rise in temperature of the fluid.

Nonlinear Analysis of Rotor-Bearing Systems Using Component Mode Synthesis

1983 ◽  
Vol 105 (3) ◽  
pp. 606-614 ◽  
Author(s):  
H. D. Nelson ◽  
W. L. Meacham ◽  
D. P. Fleming ◽  
A. F. Kascak
Keyword(s):  
Forced Response ◽  
Component Mode Synthesis ◽  
Squeeze Film ◽  
System Response ◽  
Reduced Order ◽  
Squeeze Film Dampers ◽  
Rotor Bearing ◽  
System Equations ◽  
Transient System ◽  
Blade Loss

The method of component mode synthesis is developed to determine the forced response of nonlinear, multishaft, rotor-bearing systems. The formulation allows for simulation of system response due to blade loss, distributed unbalance, base shock, maneuver loads, and specified fixed frame forces. The motion of each rotating component of the system is described by superposing constraint modes associated with boundary coordinates and constrained precessional modes associated with internal coordinates. The precessional modes are truncated for each component and the reduced component equations are assembled with the nonlinear supports and interconnections to form a set of nonlinear system equations of reduced order. These equations are then numerically integrated to obtain the system response. A computer program, which is presently restricted to single shaft systems has been written and results are presented for transient system response associated with blade loss dynamics, with squeeze film dampers, and with interference rubs.

Influence of different flow regimes on the performance characteristics of a four-pad hydrostatic squeeze film damper loaded between pads

2019 ◽  
Vol 71 (3) ◽  
pp. 440-446
Author(s):  
Amina Nemchi ◽  
Ahmed Bouzidane ◽  
Aboubakeur Benariba ◽  
Hicham Aboshighiba
Keyword(s):  
Turbulent Flow ◽  
Load Capacity ◽  
Flow Regimes ◽  
Performance Characteristics ◽  
Squeeze Film ◽  
Eccentricity Ratio ◽  
Flow Conditions ◽  
Content Type ◽  
Turbulent Flow Regime ◽  
Squeeze Film Dampers

Purpose The purpose of this paper is to study the influence of different flow regimes on the dynamic characteristics of four-pad hydrostatic squeeze film dampers (SFDs) loaded between pads. Design/methodology/approach A numerical model based on Constantinescu’s turbulent lubrication theory using the finite difference method has been developed and presented to study the effect of eccentricity ratio on the performance characteristics of four-pad hydrostatic SFDs under different flow regimes. Findings It was found that the influence of turbulent flow on the dimensionless damping of four-pad hydrostatic SFDs appears to be essentially controlled by the eccentricity ratio. It was also found that the laminar flow presents higher values of load capacity compared to bearings operating under turbulent flow conditions. Originality/value In fact, the results obtained show that the journal bearing performances are significantly influenced by the turbulent flow regime. The study is expected to be useful to bearing designers.

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