scholarly journals A Dynamic-Balancing Testing System Designed for Flexible Rotor

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shibo Zhao ◽  
Xingmin Ren ◽  
Yihao Liu ◽  
Kuan Lu ◽  
Chao Fu ◽  
...  
Keyword(s):  
Engineering Application ◽  
Maximum Amplitude ◽  
Rotor System ◽  
Testing System ◽  
Influence Coefficient ◽  
Maximum Deflection ◽  
Transient Vibration ◽  
Dynamic Balancing ◽  
Measuring Point ◽  
Vibration Responses

In this paper, a dynamic-balancing testing system is designed. The innovative feature of the testing system is the dynamic balancing of the rotor system with robustness and high balance efficiency which meets the requirements of engineering application. The transient characteristic-based balancing method (TCBM) interface and the influence coefficient method (ICM) interface are designed in the testing system. The TCBM calculates the unbalance by the transient vibration responses while accelerating rotor operating without trail-weight. The ICM calculates the unbalance by the steady-state vibration responses while the rotor system operates with trail-weight and constant speed. The testing system has the functions of monitoring operations synchronously, measuring and recording the required vibration responses, analyzing the dynamic characteristics, and identifying the unbalance parameters. Experiments of the single disc rotor system are carried out, and the maximum deflection of the measuring point has decreased by 73.11% after balancing by the TCBM interface. The maximum amplitude of the measuring point at 2914 r/min has decreased by 77.74% after balancing by ICM interface, while the maximum deflection during the whole operation has decreased by 70.00%. The experiments prove the effectiveness of the testing system, while the testing system has advantages of convenient and intuitive operation, high balance efficiency, and security.

Transient Vibration of High-Speed, Lightweight Rotors Due to Sudden Imbalance

1983 ◽  
Vol 105 (3) ◽  
pp. 480-486 ◽  
Author(s):  
M. Sakata ◽  
T. Aiba ◽  
H. Ohnabe
Keyword(s):  
Transient Response ◽  
High Speed ◽  
Rotor System ◽  
Response Analysis ◽  
Transient Vibration ◽  
Flexible Shaft ◽  
Shaft System ◽  
Transient Response Analysis ◽  
Flexible Disk ◽  
Blade Loss

In the field of rotor dynamics, increased attention is being given to the transient response analysis of the rotor, since the effects of impact loading and vibrations of the rotor arising from blade loss can be studied by a time transient solution of the rotor system. As recent trends in rotating machinery have been directed towards lightweight, high-speed flexible rotors, the effect of flexibility on transient response analysis is becoming of increasing importance. In the present paper, a transient vibration analysis is carried out on a flexible-disk/flexible-shaft system or rigid-disk flexible-shaft system subjected to a sudden imbalance that is assumed to represent the effect of blade loss. To solve the basic equation governing a rotating flexible disk the Galerkin’s method is used, and the equation of motion of the rotor system is numerically solved by employing the Runge-Kutta-Gill’s method. Experiments were conducted on a model rotor having a blade loss simulator; the shaft vibrations were also measured. The validity of the anaytical results was demonstrated by comparison with the experimental results.

Recent advances in reliability analysis of aeroengine rotor system: a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xue-Qin Li ◽  
Lu-Kai Song ◽  
Guang-Chen Bai
Keyword(s):  
Reliability Analysis ◽  
Surrogate Model ◽  
Engineering Application ◽  
Rotor System ◽  
Engineering Structures ◽  
Content Type ◽  
Reliability Design ◽  
Rotor Systems ◽  
Practical Engineering ◽  
Complex Engineering

PurposeTo provide valuable information for scholars to grasp the current situations, hotspots and future development trends of reliability analysis area.Design/methodology/approachIn this paper, recent researches on efficient reliability analysis and applications in complex engineering structures like aeroengine rotor systems are reviewd.FindingsThe recent reliability analysis advances of engineering application in aeroengine rotor system are highlighted, it is worth pointing out that the surrogate model methods hold great efficiency and accuracy advantages in the complex reliability analysis of aeroengine rotor system, since its strong computing power can effectively reduce the analysis time consumption and accelerate the development procedures of aeroengine. Moreover, considering the multi-objective, multi-disciplinary, high-dimensionality and time-varying problems are the common problems in various complex engineering fields, the surrogate model methods and its developed methods also have broad application prospects in the future.Originality/valueFor the strong demand for efficient reliability design technique, this review paper may help to highlights the benefits of reliability analysis methods not only in academia but also in practical engineering application like aeroengine rotor system.

scholarly journals Quasi-Static Characteristics and Vibration Responses Analysis of Helical Geared Rotor System with Random Cumulative Pitch Deviations

2020 ◽  
Vol 10 (12) ◽  
pp. 4403
Author(s):  
Bing Yuan ◽  
Geng Liu ◽  
Lan Liu
Keyword(s):  
Degrees Of Freedom ◽  
Transmission Error ◽  
Rotor System ◽  
Dynamic Responses ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Long Period ◽  
Light Load ◽  
Vibration Responses ◽  
Loaded Tooth Contact Analysis

As one of the long period gear errors, the effects of random cumulative pitch deviations on mesh excitations and vibration responses of a helical geared rotor system (HGRS) are investigated. The long-period mesh stiffness (LPMS), static transmission error (STE), as well as composite mesh error (CMS), and load distributions of helical gears are calculated using an enhanced loaded tooth contact analysis (LTCA) model. A dynamic model with multi degrees of freedom (DOF) is employed to predict the vibration responses of HGRS. Mesh excitations and vibration responses analysis of unmodified HGRS are conducted in consideration of random cumulative pitch deviations. The results indicate that random cumulative pitch deviations have significant effects on mesh excitations and vibration responses of HGRS. The curve shapes of STE and CMS become irregular when the random characteristic of cumulative pitch deviations is considered, and the appearance of partial contact loss in some mesh cycles leads to decreased LPMS when load torque is relatively low. Vibration modulation phenomenon can be observed in dynamic responses of HGRS. In relatively light load conditions, the amplitudes of sideband frequencies become larger than that of mesh frequency and its harmonics (MFIHs) because of relatively high contact ratio. The influences of random cumulative pitch deviations on the vibration responses of modified HGRS are also discussed.

Nonlinear Dynamic Analysis on Planetary Gears-Rotor System in Geared Turbofan Engines

2019 ◽  
Vol 29 (06) ◽  
pp. 1950076 ◽  
Author(s):  
Lanlan Hou ◽  
Shuqian Cao
Keyword(s):  
Nonlinear Dynamic Analysis ◽  
Period Doubling ◽  
Nonlinear Behavior ◽  
Rotor System ◽  
Chaotic Motions ◽  
Planetary Gears ◽  
Gear Noise ◽  
Turbofan Engines ◽  
Vibration Responses ◽  
Nonlinear Analytical Model

Rotor fatigue and gear noise triggered by nonlinear vibration are the key concerns in Geared Turbofan (GTF) engine which features a new configuration by introducing planetary gears into low-pressure compressor. A nonlinear analytical model of the GTF planetary gears-rotor system is developed, where the torsional effect of rotor and pivotal parameters from gears are incorporated. The nonlinear behavior of the model can be obtained by focusing on the relative torsional vibration responses between gear and rotor. The torsional nonlinear responses are illustrated with bifurcation diagrams, the largest Lyapunov exponents (LLE), Poincaré maps, phase diagrams and spectrum waterfall. Numerical results reveal that the gears-rotor system exhibits abundant torsional nonlinear behaviors, including multiperiodic, quasi-periodic, and chaotic motions. Furthermore, the roads to chaos via quasi-periodicity, period-doubling scenario, mutation and intermittence are demonstrated. The ring gear stiffness at a low value can propel the system into chaos. The damping may complicate the motion, i.e. the system may enter chaos with increasing damping. These results provide an understanding of undesirable torsional dynamic motion for the GTF engine rotor system and therefore serve as a useful reference for engineers in designing and controlling such system.

Optimization of LM2500 Gas Generator and Power Turbine Trim Balance Techniques

1991 ◽  
Author(s):  
Bruce D. Thompson
Keyword(s):  
Success Rate ◽  
Maximum Amplitude ◽  
Turbine Rotor ◽  
Theoretical Background ◽  
Influence Coefficient ◽  
Gas Generator ◽  
Imbalance Problem ◽  
Influence Coefficients ◽  
Power Turbine ◽  
Good Set

A procedure has been developed by the U.S. Navy to trim balance, in-place, the gas generator and power turbine rotor of the LM2500 Marine Gas Turbine Engine. This paper presents the theoretical background and the techniques necessary to optimize the procedure to balance the gas generator rotor. Additionally, a method was developed to trim balance LM2500 power turbines. To expand the implementation of both gas generator and power turbine trim balancing, a capability had to be developed to minimize the effort required (trial weight runs etc.). The objective was to able to perform consistently what are called “First Shot” trim balances. “First Shot” trim balances require only one weight placement to bring the engine vibration levels to within the specified goals (less than .002 of an inch maximum amplitude) and that being the final trim weight. It was realized that the Least Squares Influence Coefficient method, even with a good set of averaged influence coefficients, can lead to a number of trial weight experiments before the final trim weights can be placed. The method used to maximize the possibility of obtaining a “First Shot” trim balance was to use modal information to tailor the influence coefficient sets to correct the most predominant and correctable imbalance problem. Since the influence coefficients were tailored, it became necessary to be able to identify, in the initial vibration survey, the type of response a particular LM2500 has. Using modal information obtained from a LM2500 rotor dynamics model and from the early trim balance efforts it was possible to identify the modal response of a given LM2500 and optimize the trim balance of that engine. With these improved techniques a 70% success rate for “First Shot” trim balance has been achieved and the success rate of the trim balance procedure, as a whole, has been near 100%.

Analysis of mistuned forced response in an axial high-pressure compressor rig with focus on Tyler–Sofrin modes

2019 ◽  
Vol 123 (1261) ◽  
pp. 356-377
Author(s):  
F. Figaschewsky ◽  
A. Kühhorn ◽  
B. Beirow ◽  
T. Giersch ◽  
S. Schrape
Keyword(s):  
Axial Compressor ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Operating Conditions ◽  
Cfd Simulations ◽  
High Pressure Compressor ◽  
Engine Order ◽  
Stator Vane ◽  
Vibration Responses ◽  
The Impact

ABSTRACTThis paper aims at contributing to a better understanding of the effect of Tyler–Sofrin Modes (TSMs) on forced vibration responses by analysing a 4.5-stage research axial compressor rig. The first part starts with a brief review of the involved physical mechanisms and necessary prerequisites for the generation of TSMs in multistage engines. This review is supported by unsteady CFD simulations of a quasi 2D section of the studied engine. It is shown that the amplitude increasing effect due to mistuning can be further amplified by the presence of TSMs. Furthermore, the sensitivity with respect to the structural coupling of the blades and the damping as well as the shape of the expected envelope is analysed.The second part deals with the Rotor 2 blisk of the research compressor rig. The resonance of a higher blade mode with the engine order of the upstream stator is studied in two different flow conditions realised by different variable stator vane (VSV) schedules which allows to separate the influence of TSMs from the impact of mistuning. A subset of nominal system modes representation of the rotor is used to describe its mistuned vibration behaviour, and unsteady CFD simulations are used to characterise the present strength of the TSMs in the particular operating conditions. Measured maximum amplitude vs blade pattern and frequency response functions are compared against the predictions of the aeromechanical models in order to assess the strength of the TSMs as well as its influence on vibration levels.

scholarly journals A method to select correcting faces of a double-face dynamic balancing rotor

2016 ◽  
Vol 8 (12) ◽  
pp. 168781401668289
Author(s):  
Shihai Zhang ◽  
Zimiao Zhang
Keyword(s):  
Influence Coefficient ◽  
Axial Distribution ◽  
Dynamic Balancing ◽  
The Real ◽  
Influence Coefficients ◽  
Total Phase ◽  
Influence Coefficient Method ◽  
Phase Variations ◽  
Distribution Laws ◽  
Design And Practice

Considering the sensitivity and installing position limitation, the real positions for two correcting faces must be selected first in the process of double-face dynamic balancing design and practice for rigid rotor system. According to the principle of influence coefficient method, series of testing weight experiments are conducted in this article. Based on the experimental results, the axial distribution laws of the amplitudes and phases of influence coefficients are found and summarized as follows: the amplitude variations of influence coefficients are very small and the phase variations of influence coefficients are obvious when the correcting positions are changed along shaft, so the phases of influence coefficients have the key effect on the correcting vector in correcting faces. Based on this fact, the total phase difference maximum method of influence coefficients is proposed to select the real axial positions for correcting faces. The principle of the method is analyzed in theory, and the application effect is tested by double-face dynamic balancing experiments.

scholarly journals Intelligent Approach to Robust Design Optimization of a Rotor System due to Its Support Stiffness Uncertainty

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Bensheng Xu ◽  
Chaoping Zang ◽  
Genbei Zhang
Keyword(s):  
Design Optimization ◽  
Robust Design ◽  
System Performance ◽  
Polynomial Chaos ◽  
Low Pressure ◽  
Polynomial Chaos Expansion ◽  
Rotor System ◽  
Robust Design Optimization ◽  
Chaos Expansion ◽  
Vibration Responses

In this paper, an intelligent robust design approach combined with different techniques such as polynomial chaos expansion (PCE), radial basis function (RBF) neural network, and evolutionary algorithms is presented with a focus on the optimization of the dynamic response of a rotor system considering support stiffness uncertainty. In the proposed method, the PCE method instead of the traditional Monte Carlo uncertainty analysis is applied to analyze the uncertain propagation of system performance. The RBF network is introduced to establish the approximate models of the objective and constraint functions. Taking the low-pressure rotor of a gas turbine with support stiffness uncertainty as an example, the optimization model is established with the mean and variance of unbalanced response of the rotor system at different operating speeds as the objective function, and the maximum unbalance response is less than the upper limit as the constraint function. The polynomial chaos expansion is generated to facilitate a rapid analysis of robustness in the presence of support stiffness uncertainties that is defined in terms of tolerance with good accuracy. The optimal Hypercubus are used as experimental plans for building RBF approximation models of the objective and constraint functions. Finally, the robust solutions are obtained with the multiobject optimization algorithm NSGA-II. Monte Caro simulation analysis demonstrates that the qualified rate of maximum vibration responses of the low-pressure rotor system can be increased from 83.6% to over 99%. This approach to robust design optimization is shown to lead to designs that significantly decrease vibration responses of the rotor system and improved system performance with reduced sensitivity to support stiffness uncertainty.

Study on an Intelligent Teaching Dynamic Balance Technology

2013 ◽  
Vol 483 ◽  
pp. 174-176 ◽  
Author(s):  
Shu Ping Cai ◽  
Ting Zhao
Keyword(s):  
Dynamic Balance ◽  
Far Infrared ◽  
Test System ◽  
Influence Coefficient ◽  
Dynamic Balancing ◽  
Influence Coefficient Method ◽  
Sensitive Sensor ◽  
Phase Sensor ◽  
Electric Measuring ◽  
Coefficient Method

Abstract:.:Intelligent teaching Dynamic balancing is a new kind of dynamic balancing test system with various functions of teaching need. It integrates the hard bearing method using A, B, C size solution with soft bearing method using the influence coefficient method solution. The system is mainly composed of machine frame, intelligent electric measuring box, high sensitive sensor and far infrared phase sensor. It has the advantages of small volume, simple operation, security with low speed，reliable and convenient operation for students. It can deepen students' understanding of balancing knowledge, which has won the national utility model patent.

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