A theoretical and experimental investigation into the vibration response of a flexible rotor and squeeze-film damper assembly

Siew, C.C.; Hill, Martyn; Holmes, R.; Brennan, M.J.

doi:10.1177/095440620121500109

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…The SFD (9) is oil film between the bearing housing (10) and the journal (8), which is the outer race of a rolling element bearing (see also Figure 3). Shaft rotation is irrelevant to the SFD input-output relationship since, in all rotordynamic applications, the SFD journal is prevented from rotating using dogs or retainer springs but allowed to orbit in the x-y plane within the oil-filled clearance.…”

Section: Test Rig Descriptionmentioning

confidence: 99%

“…However, this database was severely limited since it was based on a theoretical model that assumes that the bearing force could be expressed as the product of an amplitude-dependent coefficient and the vibration. From basic SFD theory [8], this theoretical model is only valid for the case of uncavitated SFDs with journals undergoing circular orbits that are concentric with the circular clearance bore. Apart from being highly idealized, this assumption limited the full inverse problem solved by Dicken et al [2] to isotropic conditions and their work was not experimentally validated.…”

Section: Introductionmentioning

confidence: 99%

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Improved Empirical Identification of the Inverse Model of a Squeeze-Film Damper Bearing Based on a Recurrent Neural Network

Al-Ghazal

Bonello

Cedillo

2018

Volume 7A: Structures and Dynamics

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Most recently proposed techniques for inverse rotordynamic problems seek to identify the unbalance on a rotor using a known structural model and measurements from externally mounted sensors only. Such non-intrusive techniques are important for balancing rotors that cannot be accessed under operational conditions because of temperature or space restrictions. The presence of nonlinear bearings, like squeeze-film damper (SFD) bearings used in aero-engines, complicates the solution process of the inverse rotordynamic problem. In certain practical aero-engine configurations, the solution process requires a substitute for internal instrumentation to quantify the SFD journal vibration. This can be provided by an inverse model of the SFD bearing which outputs the time history of the relative vibration of the SFD journal relative to its housing, for a given input time history of the SFD force. This paper focuses on the inverse model of the SFD and presents an improved methodology for its identification via a Recurrent Neural Network (RNN) trained using experimental data from a purposely designed rig. The novel application of chirp excitation via two orthogonal shakers considerably improves both the quality of the training data and the efficiency of its generation, relative to an earlier preliminary work. Validation test results show that the RNNs can predict the journal displacement time history with reasonable accuracy. It is therefore expected that such an inverse SFD model would serve as a reliable component in the solution of the wider inverse problem of a rotordynamic system.

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Section: Test Rig Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Empirical Identification of the Inverse Model of a Squeeze-Film Damper Bearing Based on a Recurrent Neural Network

Al-Ghazal

Bonello

Cedillo

2018

Volume 7A: Structures and Dynamics

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“…Siew et al. 3 investigated the unbalanced flexible rotating system squeeze-film damper and retainer springs under different conditions. In another research, Liu et al.…”

Section: Introductionmentioning

confidence: 99%

Dynamic stability and bifurcation phenomena of an axially loaded flexible shaft-disk system supported by flexible bearing

Phadatare

Pratiher

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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The present research studies the vibration and bifurcation analysis of a spinning rotor-disk-bearing system to carefully scrutinize the dynamic stability under extrinsic mass unbalance and pulsating axial load. The shaft is flexible and taken into account the geometrical nonlinearities due to large elastic deformation in bending. The rotor is supported by flexible bearings, which are modeled as an equivalent spring-damper system having linear and nonlinear stiffness elements. Equation of motion of the rotating system, which includes flexible shaft, rigid disk, and flexible bearing, is derived using extended Hamilton principle with the assumption of the Euler's beam theory. We studied initially the modal analysis to determine the modal parameters, i.e. natural frequency and mode shapes prior to the investigation of the dynamics of the system. Further, we developed the bifurcation diagram for steady-state solutions and to study the subsequent dynamic stability and verify with the findings solved numerically. The interactive behavior among the nonlinear shaft-bearing, axial load and an unbalance has been analyzed. Numerical simulation tools, i.e. frequency–response characteristics, time history, phase trajectories, and Poincaré map have been used to highlight the presence of nonlinear phenomena and its important role towards evaluating the system dynamics and subsequent stability. This current research showed that flexible bearings stabilize the system as a result of increasing the restoring force. Analyzing the bifurcation diagrams of pulsating axial load, we found that the system exhibits complex phenomena as multiple but stable periodic orbits leading to period doubling. The present system is highly vulnerable to catastrophic failure due to the S–N and Pitchfork bifurcation. The present research enables the notability of axial load and mechanical unbalance on the overall system behavior and stability in real working conditions.

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“…The damping performance of the linear guide is far from that of the slide guide in machine tools. 3 Many studies 4,5 show that damping oil films, applied in the mechanical system, can achieve a better damping performance. Therefore, oil-film damping technology can be applied into the linear guideway.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the damping capacity of the linear damper with an oil groove in the linear guideway system

Feng

Chen

et al. 2017

Advances in Mechanical Engineering

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This article presents an experimental investigation into the damping characteristics of a linear damper with a newly designed oil groove. The damping performance of the damper is tested in four different viscosity grades by the sweep frequency method. And a test bench is used to move the damper for a several kilometers to examine the damping maintenance. The experimental results show that a higher oil viscosity leads to a higher damping capacity of the linear damper, and the increase in the oil viscosity will improve the damping maintenance of the damper. The newly designed oil groove efficiently improved the damping capacity of the linear damper; a proper oil selection will further optimize the effect of the oil groove via minimizing the oil leakage.

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A theoretical and experimental investigation into the vibration response of a flexible rotor and squeeze-film damper assembly

Cited by 5 publications

References 18 publications

Improved Empirical Identification of the Inverse Model of a Squeeze-Film Damper Bearing Based on a Recurrent Neural Network

Improved Empirical Identification of the Inverse Model of a Squeeze-Film Damper Bearing Based on a Recurrent Neural Network

Dynamic stability and bifurcation phenomena of an axially loaded flexible shaft-disk system supported by flexible bearing

Improvement of the damping capacity of the linear damper with an oil groove in the linear guideway system

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