Fault Diagnosis on an Aircraft Engine Model Equipped With Self-Sensing Piezoelectric Actuators

2016 ◽  
Author(s):  
Ramakrishnan Ambur ◽  
Xiaonan Zhao ◽  
Stephan Rinderknecht
Keyword(s):  
Fault Diagnosis ◽  
Piezoelectric Materials ◽  
Piezoelectric Actuators ◽  
Aircraft Engine ◽  
Axial Direction ◽  
Squeeze Film ◽  
Sensors And Actuators ◽  
Rotor Systems ◽  
Engine Model ◽  
Squeeze Film Dampers

Piezoelectric actuators provide an active solution for vibration control in aircraft engines compared to the state-of-the-art squeeze film dampers. The property of piezoelectric materials enable them to be used as sensors and actuators simultaneously. This self-sensing property of the actuator is analyzed in this paper for its ability to detect unbalance faults, which are common in rotor systems. In this paper two different actuator configurations are studied for its ability to diagnose unbalance faults in an aircraft engine. Three parameters of unbalances such as its magnitude, its position in the circumferential and axial direction in a rotor are estimated through simulations. Finally a suitable position to achieve a better fault diagnosis is identified.

scholarly journals Dynamic Behavior of Geared Rotors

1997 ◽  
Author(s):  
T. N. Shiau ◽  
J. S. Rao ◽  
J. R. Chang ◽  
Siu-Tong Choi
Keyword(s):  
Dynamic Behavior ◽  
Chaotic Behavior ◽  
Squeeze Film ◽  
Rotor Systems ◽  
Lateral Vibrations ◽  
Squeeze Film Dampers ◽  
Torsional Excitation ◽  
Route To Chaos

This paper is concerned with the dynamic behavior of geared rotor systems supported by squeeze film dampers, wherein coupled bending torsion vibrations occur. Considering the imbalance forces and gravity, it is shown that geared rotors exhibit chaotic behavior due to non linearity of damper forces. The route to chaos in such systems is established. In geared rotor systems, it is shown that torsional excitation can induce lateral vibrations. It is shown that squeeze film dampers can suppress large amplitudes of whirl arising out of torsional excitation.

scholarly journals Squeeze-Film Damper Technology: Part 1 — Prediction of Finite Length Damper Performance

1983 ◽  
Author(s):  
J. W. Lund ◽  
A. J. Smalley ◽  
J. A. Tecza ◽  
J. F. Walton
Keyword(s):  
Finite Length ◽  
Gas Turbines ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Strongly Coupled ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Squeeze Film Dampers ◽  
Calculation Results

Squeeze-film dampers are commonly used in gas turbine engines and have been applied successfully in a great many new designs, and also as retrofits to older engines. Of the mechanical components in gas turbines, squeeze-film dampers are the least understood. Their behavior is nonlinear and strongly coupled to the dynamics of the rotor systems on which they are installed. The design of these dampers is still largely empirical, although they have been the subject of a large number of past investigations. To describe recent analytical and experimental work in squeeze-film damper technology, two papers are planned. This abstract outlines the first paper, Part 1, which concerns itself with squeeze-film damper analysis. This paper will describe an analysis method and boundary conditions which have been developed recently for modelling dampers, and in particular, will cover the treatment of finite length, feed and drain holes and fluid inertia effects, the latter having been shown recently to be of great importance in predicting rotor system behavior. A computer program that solves the Reynolds equation for the above conditions will be described and sample calculation results presented.

Design of Nonlinear Squeeze-Film Dampers for Aircraft Engines

1977 ◽  
Vol 99 (1) ◽  
pp. 57-64 ◽  
Author(s):  
E. J. Gunter ◽  
L. E. Barrett ◽  
P. E. Allaire
Keyword(s):  
Reynolds Equation ◽  
Nonlinear Effects ◽  
Aircraft Engine ◽  
Squeeze Film ◽  
Aircraft Engines ◽  
Transient Method ◽  
Squeeze Film Damper ◽  
Wide Range ◽  
Squeeze Film Dampers ◽  
Bearing Stiffness

This paper examines the effect of squeeze-film damper bearings on the steady state and transient unbalance response of aircraft engine rotors. The nonlinear effects of the damper are examined, and the variance of the motion due to unbalance, static pressurization, retainer springs, and rotor preload is shown. The nonlinear analysis is performed using a time-transient method incorporating a solution of the Reynolds equation at each instant in time. The analysis shows that excessive stiffness in the damper results in large journal amplitudes and transmission of bearing forces to the engine casing which greatly exceed the unbalance forces. Reduction of the total effective bearing stiffness through static pressurization and rotor preload is considered. The reduction in stiffness allows the damping generated by the bearing to be more effective in attenuating rotor forces. It is observed that in an unpressurized damper, the dynamic transmissibility will exceed unity when the unbalance eccentricity exceeds approximately 50 percent of the damper clearance for the relatively wide range of conditions examined in this study.

scholarly journals Parameter Analysis of an Intershaft Dual-Rotor with the Application of Squeeze Film Dampers

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Huizheng Chen ◽  
Shun Zhong ◽  
Zhenyong Lu ◽  
Yushu Chen ◽  
Xiyu Liu
Keyword(s):  
Vibration Suppression ◽  
Rotor System ◽  
Parameter Analysis ◽  
Dynamical Analysis ◽  
Squeeze Film ◽  
Physical Parameters ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Squeeze Film Dampers ◽  
Frequency Curves

The squeeze film damper is usually adopted in the rotor system to suppress the vibrating motion of the rotor system. In this work, not only are the physical parameters of the squeeze film damper analyzed but also the system parameters, like the number of squeeze film dampers used and squeeze film damper implementation positions, are analyzed. The amplitude-frequency curves are obtained by conducting the simulation of a dual-rotor, intershaft, and oil film force concatenated model. Through the analysis and comparisons of the results, the vibration suppression effects of the squeeze film damper with different parameter configurations are analyzed and summarized. This work contributes to further optimization and dynamical analysis work on rotor systems with the application of the squeeze film damper.

Use of the Harmonic Balance Method for Flexible Aircraft Engine Rotors With Nonlinear Squeeze Film Dampers

2014 ◽  
Author(s):  
Feng He ◽  
Paul Allaire ◽  
Timothy Dimond
Keyword(s):  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Aircraft Engine ◽  
Balance Method ◽  
Squeeze Film ◽  
Spring Stiffness ◽  
Squeeze Film Damper ◽  
Flexible Rotors ◽  
Squeeze Film Dampers ◽  
Nonlinear Transient

Squeeze film dampers in flexible rotors such as those in compressors, steam turbines, aircraft engines and other rotating machines are often modeled as linear devices. This linearization is valid only for a specified orbit where appropriate equivalent stiffness and damping coefficients can be found. However, squeeze film dampers are inherently nonlinear devices which complicates the analysis. This paper develops the harmonic balance method with a direct force model of the SFDs. This model is used for flexible rotors with squeeze film dampers where the rotor is treated as linear and the squeeze film damper is treated as nonlinear. The predictor-corrector method is employed to obtain the system forced response in the frequency domain after separating the nonlinear components from the linear components of the equations of motion. This approach is much more efficient than conventional full nonlinear transient analysis. The application considered in this paper is the low pressure (LP) compressor of an aircraft engine. The LP compressor rotor has two roller bearings with squeeze film dampers and one ball bearing without a squeeze film damper. Orbits at the fan end dampers and the turbine end dampers for both the harmonic balance and nonlinear transient modeling are compared for accuracy and calculation time. The HB method is shown to be 5 to 12 times faster computationally for similar results. Fast Fourier transform results were obtained for various shaft operating speeds. Results were also obtained for the unbalance response at different locations with gravity loading. Finally, unbalance response of the rotor with varying centering spring stiffness values were obtained. The results show that the centering spring stiffness for the turbine end damper is less sensitive than the fan end damper.

Squeeze-Film Damper Predictions for Simulation of Aircraft Engine Rotordynamics

2004 ◽  
Author(s):  
Cyril Defaye ◽  
Franck Laurant ◽  
Philippe Carpentier ◽  
Mihai Arghir ◽  
Olivier Bonneau ◽  
...  
Keyword(s):  
Reynolds Equation ◽  
Aircraft Engine ◽  
Theoretical Work ◽  
Analytical Models ◽  
Squeeze Film ◽  
Design Parameters ◽  
Aircraft Engines ◽  
Predictive Tool ◽  
Squeeze Film Dampers ◽  
Inertia Forces

On aircraft engines, a common recurring problem is excessive vibration levels generated by unbalance. With rotors mounted on usual undamped ball bearings, an amount of damping is required to limit peak amplitudes at traversed critical speeds: a solution is to introduce external damping with squeeze-film dampers. Such dampers can be added with minor modifications of the rotor system design. This paper presents experimental and theoretical work in progress focused on the analysis of squeeze film dampers (SFD) based on serial aircraft engines design. Several squeeze-film geometries were tested to measure the influence of different design parameters as the fluid clearance and the groove feeding system. Next, a damper model based on the numerical solution of the Reynolds equation is correlated with the experimental data to obtain predictive global forces. It is shown that the theoretical model is a good predictive tool if it is correctly adjusted and if temporal inertia forces are negligible. The present damper model is further compared with analytical models taken from the literature which are obviously more appropriate to be used in whole engine rotordynamic analysis. The limits of the models are then underlined by comparisons with experimental results.

Calculated Rotordynamic Behaviour of a Twin Spool Engine and the Comparison With Test Results

1995 ◽  
Author(s):  
B. Domes ◽  
H. Hartmüller ◽  
G. Tokar ◽  
G. Wang
Keyword(s):  
Dynamic Behaviour ◽  
Complex Structure ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Test Results ◽  
Engine Model ◽  
Damping Characteristics ◽  
Resonance Frequencies ◽  
Squeeze Film Dampers ◽  
Good Agreement

Abstract The new BR 700 series of twin spool engines, of the thrust class of 15,000 to 20,000 pounds, is being developed for business jets. In this paper the rotordynamic vibration analysis is performed with a detailed whole engine model including both rotors, bearings with oil squeeze film dampers and squirrel cages, the engine structure, the mounts and the fuselage. The analytical method is described and some calculated results are presented. The effectiveness of the oil squeeze film dampers on all main bearings will be demonstrated. The comparison of the analytical and the measured results gives a good agreement in the resonance frequencies and in the damping characteristics. It also shows that a linear analysis can describe with sufficient accuracy the dynamic behaviour of such a complex structure like a twin spool engine under normal operating conditions.

Gas Turbine Engine Gas-path Fault Diagnosis Based on Improved SBELM Architecture

2018 ◽  
Vol 35 (4) ◽  
pp. 351-363 ◽  
Author(s):  
Feng Lu ◽  
Jipeng Jiang ◽  
Jinquan Huang
Keyword(s):  
Fault Diagnosis ◽  
Aircraft Engine ◽  
Learning Technologies ◽  
Data Driven ◽  
Turbine Engine ◽  
Engine Model ◽  
Performance Deterioration ◽  
Diagnostic Approaches ◽  
Gas Path Fault ◽  
Learning Machine

Abstract Various model-based methods are widely used to aircraft engine fault diagnosis, and an accurate engine model is used in these approaches. However, it is difficult to obtain general engine model with high accuracy due to engine individual difference, lifecycle performance deterioration and modeling uncertainty. Recently, data-driven diagnostic approaches for aircraft engine become more popular with the development of machine learning technologies. While these data-driven methods to engine fault diagnosis tend to ignore experimental data sparse and uncertainty, which results in hardly achieve fast fault diagnosis for multiple patterns. This paper presents a novel data-driven diagnostic approach using Sparse Bayesian Extreme Learning Machine (SBELM) for engine fault diagnosis. This methodology addresses fast fault diagnosis without relying on engine model. To enhance the reliability of fast fault diagnosis and enlarge the detectable fault number, a SBELM-based multi-output classifier framework is designed. The reduced sparse topology of ELM is presented and utilized to fault diagnosis extended from single classifier to multi-output classifier. The effects of noise and measurement uncertainty are taken into consideration. Simulation results show the SBELM-based multi-output classifier for engine fault diagnosis is superior to the existing data-driven ones with regards to accuracy and computational efforts.

Optimum Design of Squeeze Film Dampers Supporting Multiple-Mode Rotors

2002 ◽  
Vol 124 (4) ◽  
pp. 992-1002 ◽  
Author(s):  
A. El-Shafei ◽  
R. Y. K. Yakoub
Keyword(s):  
Optimum Design ◽  
Critical Speed ◽  
Aircraft Engine ◽  
Squeeze Film ◽  
Operating Speed ◽  
Spring Stiffness ◽  
Search Technique ◽  
Amplitude Response ◽  
Design Program ◽  
Squeeze Film Dampers

In this paper a study of the optimum design of squeeze film dampers for multimode rotors is presented. The optimum design program obtains the best possible damper parameters for a given rotor to satisfy the minimization requirements for the objective function. The objectives are to minimize the amplitude response of the rotor at the critical speed, minimize the force transmitted to the support at the operating speed, or maximize the power dissipated by the damper. A combination of these objectives can also be used, with weighting factors to weigh the importance of each of these objectives. These are the possible objectives for the design of squeeze film dampers for aircraft engine applications. The basis of the optimum design program is an extremely fast algorithm which is able to quickly calculate the unbalance response of a rotor, for circular centered orbits of the journal in the damper. A commercial routine is used for the optimization, and is based on a complex direct search technique. The variation of the optimum clearance, length, and retainer spring stiffness are plotted against various rotor parameters. Recommendations for the design of squeeze film dampers are made. Applications to an aircraft engine illustrate the power of the developed algorithm.

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