Simulation of Rotor System Vibrations Using Experimentally Verified Super Elements

2016 ◽  
Author(s):  
Sergei Semenov ◽  
Mikhail Nikhamkin ◽  
Nikolai Sazhenkov ◽  
Irina Semenova ◽  
Grigorii Mekhonoshin
Keyword(s):  
Numerical Technique ◽  
Element Model ◽  
3D Models ◽  
Rotor System ◽  
Vibration Modes ◽  
Frequency Range ◽  
Test Rig ◽  
Rotor Systems ◽  
Operating Frequency Range ◽  
Analysis Of Results

A numerical technique based on finite element model reduced by using experimentally verified superelements is presented in the paper. This method can be used for modelling of rotor systems with elements which can produce nonaxisymmetrical vibration modes (fan, flexible disks and etc.) in operating frequency range thus forcing to calculate 3D models without cycle symmetry. Testing of proposed mathematical modeling method is produced using special rotor test rig. The procedure of superelements creation and verification is provided. Critical speeds of test rotor system were determined numerically and experimentally. Comparative analysis of results is provided.

Effects of tip relief on vibration responses of a geared rotor system

2013 ◽  
Vol 228 (7) ◽  
pp. 1132-1154 ◽  
Author(s):  
Hui Ma ◽  
Jian Yang ◽  
Rongze Song ◽  
Suyan Zhang ◽  
Bangchun Wen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Spur Gear ◽  
Rotor System ◽  
Time Varying ◽  
Frequency Range ◽  
Mesh Stiffness ◽  
Resonance Frequencies ◽  
Vibration Responses

Considering tip relief, a finite element model of a spur gear pair in mesh is established by ANSYS software. Time-varying mesh stiffness under different amounts of tip relief is calculated based on the finite element model. Then, a finite element model of a geared rotor system is developed by MATLAB software considering the effects of time-varying mesh stiffness and constant load torque. Emphasis is given to the effects of tip relief on the lateral–torsional coupling vibration responses of the system. The results show that as the amount of tip relief increases, the saltation of time-varying mesh stiffness reduces at the position of approach action and transition mesh region from the single tooth to double tooth. A number of primary resonances and some super-harmonic of gears 1 and 2 are excited by time-varying mesh stiffness in amplitude frequency responses. As the amount of tip relief increases, some super-harmonic responses change due to the variation in the higher frequency components of time-varying mesh stiffness. After tip relief, the vibration and meshing force decrease obviously at lower mesh frequency range except at some resonance frequencies; however, tip relief is not effective in reducing the vibration at higher mesh frequency range. The amplitude fluctuation of the vibration acceleration reduces evidently after considering tip relief, which is not remarkable with the increase of meshing frequency.

scholarly journals Dynamics of Flexible Rotor Systems with an Interim Mass Unbalanced Disk Using a Spectral Element Model

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
Sangkyu Choi ◽  
Usik Lee
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Element Model ◽  
Spectral Element ◽  
Rotor System ◽  
Dynamic Responses ◽  
Disk System ◽  
Unbalanced Mass ◽  
Rotor Systems ◽  
Blade System

A frequency domain spectral element model is developed for a rotor system that consists of two spinning shafts and an interim disk or blade system. In this study, the shafts are represented by spinning Timoshenko beam models, and the interim disk system is represented by a uniform thick rigid disk with an unbalanced mass. In our derivation of the governing equations of motion of the disk system, the disk is considered to be wobbling about the geometric center of the disk at which the spinning shafts are attached. The high accuracy of the proposed spectral element model is evaluated by comparison with the natural frequencies obtained using the conventional finite element method (FEM). The spectral element model is then used to investigate the effects of the unbalanced mass on the natural frequencies and dynamic responses of an example rotor system.

Mitigation of nonlinear rub-impact of a rotor system with magnetorheological damper

2019 ◽  
Vol 31 (3) ◽  
pp. 321-338
Author(s):  
Jun Wang ◽  
Liang Ma ◽  
Junhong Zhang ◽  
Xin Lu ◽  
YangYang Yu
Keyword(s):  
Magnetic Field Intensity ◽  
Element Model ◽  
Considerable Effect ◽  
Rotor System ◽  
Magnetorheological Damper ◽  
Self Healing ◽  
Nonlinear Dynamic Response ◽  
Rotor Systems ◽  
Adaptive Ability ◽  
The Relationship

In this work, a new method of using a magnetorheological damper to improve the self-adaptive ability of a rotor system to rub-impact is developed. To validate the feasibility of this method, a finite element model of the rub-impact rotor system with magnetorheological damper is investigated. A revised formula describing the relationship between the yielding shear stress and magnetic field intensity is proposed. Focusing on the mitigation effect of magnetorheological damper on the nonlinear dynamic response of the rotor system, numerical simulation is conducted. The results show that magnetorheological damper has a considerable effect on the vibration and stability of a rub-impact rotor system. When a suitable current is applied, magnetorheological damper can effectively mitigate the vibration of the rotor system to prevent rub-impact. If contact of the rotor/stator is inevitable, magnetorheological damper can further stabilize heavy rub-impact to slight rub-impact by adjusting the current to an appropriate value. This research reveals the influence mechanisms of magnetorheological damper on normal and rub-impact rotor systems and is helpful for vibration control and fault self-healing of rotating machinery.

scholarly journals Time Frequency Features of Rotor Systems with Slowly Varying Mass

2011 ◽  
Vol 18 (1-2) ◽  
pp. 29-44
Author(s):  
Tao Yu ◽  
Qingkai Han
Keyword(s):  
Numerical Method ◽  
Element Model ◽  
Rotor System ◽  
Analytic Method ◽  
Rotor Systems ◽  
Time Frequency ◽  
First Order ◽  
General Rules ◽  
Frequency Features ◽  
Varying Mass

With the analytic method and numerical method respectively, the asymptotic solutions and finite element model of rotor system with single slowly varying mass is obtained to investigate the time frequency features of such rotor system; furthermore, with given model of slowly varying mass, the rotor system with dual slowly varying mass is studied. For the first order approximate solution is used, there exists difference between the results with analytic method and numerical method. On the base of common characteristics of rotor system with dual slowly varying mass, the general rules and formula describing the frequency distribution of rotor system with multiple slowly varying mass are proposed.

A Lower Pad Adjustable Bearing Reducing Vibration Response of Rotor Systems During Acceleration

2019 ◽  
Author(s):  
Lei Zhang ◽  
Hua Xu ◽  
Shenglun Zhang ◽  
Shiyuan Pei
Keyword(s):  
Critical Speed ◽  
Vibration Suppression ◽  
Load Condition ◽  
Element Model ◽  
Rotor System ◽  
Vibration Response ◽  
Resonance Amplitude ◽  
Suppression Effect ◽  
Rotor Systems ◽  
Light Load

Abstract A lower pad movable bearing is proposed which has the ability to change the lubricating performance of the journal bearing. The structure and working principle of the adjustable bearing are introduced. This bearing can adjust the working status of the rotor system by changing the position of the bearing pad and reduces the vibration amplitude of rotor. In this paper, a simple rotor bearing finite element model is used to study the vibration response of the rotor system. Through research, it is found that larger ellipticity can effectively reduce the amplitude of the rotor when the rotor speed is running at a certain speed away from the critical speed, and the vibration suppression effect can reach 67%. When the rotor passes the critical speed, reducing the ellipticity can significantly reduce the resonance amplitude of the rotor, and the vibration suppression effect reaches about 37%. In addition, when the rotational speed increases to twice the critical speed, the oil film oscillation occurs under light load condition, which can be suppressed by reducing the ellipticity. Adjustable bearing can then be proposed to adaptively improve the vibration of the rotor system based on the rotor speeds.

scholarly journals Numerical Investigation on the Gravity Response of a Two-Pole Generator Rotor System with Interval Uncertainties

2019 ◽  
Vol 9 (15) ◽  
pp. 3036 ◽  
Author(s):  
Zhaoli Zheng ◽  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Material Properties ◽  
Equations Of Motion ◽  
Deep Understanding ◽  
Element Model ◽  
Rotor System ◽  
Scanning Method ◽  
Rotor Systems ◽  
Generator Rotor ◽  
Gravity Response ◽  
Asymmetric Rotor

Asymmetric rotor systems widely exist in commercial plants. In the previous studies about asymmetric rotor systems, parameters such as material properties and boundary conditions are deterministic. To obtain a deep understanding of the dynamics of asymmetric rotor systems, a generator rotor system considering uncertain factors is studied in this paper. The equations of motion of the three-dimensional finite element model are solved in the rotating frame. The component mode synthesis is used to reduce the degrees of freedom. By employing the Chebyshev interval method (CIM), the uncertain gravity responses of the generator rotor system are investigated. The influences of the uncertainties in the bearing’s properties and the rotor’s material properties on the gravity response are studied in cases with a single uncertainty and double uncertainties. The accuracy and the efficiency of CIM are validated by comparing with the results of the scanning method. The results show that uncertainties have remarkable influences on the gravity response, and that these influences are different from each other. The proposed method and the results can provide guidance to the design and optimization of the rotary machinery.

Finite Element Analysis for Vibration Characteristic on Gear Rotors

2013 ◽  
Vol 273 ◽  
pp. 193-197
Author(s):  
Hong Yu Qi ◽  
Lei Liu
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Helix Angle ◽  
Forced Response ◽  
Rotor System ◽  
Ansys Software ◽  
Element Analysis ◽  
Rotor Systems ◽  
Rotational Motions ◽  
Marine Applications

Gear rotor systems are widely used in many automotive, aerospace and marine applications. Dynamic analysis of gear rotor systems is essential in describing noise and durability characteristics. Using ANSYS software, a finite-element model for a gear rotor system on flexible bearing has been developed, with MARTIX element, beam element and mass element simulating mesh-couple relation and support bearing, shaft and gear individually. The dynamic coupling among the axial, transverse, tensional and rotational motions of gears are considered in the model. The harmonic analysis and forced response of the system were analyzed. The effect of bearing compliances, shaft compliances and helix angle on system dynamics were investigated. The feasibility of the method was verified, the model and result can be used for dynamic design of gear rotor system.

ACCURACY RATING MEASUREMENT OF VIBRATION ELECTROMECHANICAL DEVICES

2019 ◽  
Vol 1 (7) ◽  
pp. 42-45
Author(s):  
V. A. Golubkov ◽  
V. F. Shishlakov ◽  
A. G. Fedorenko ◽  
E. Yu. Vataeva
Keyword(s):  
Technical Condition ◽  
Rotor System ◽  
Vibration Measurement ◽  
Random Errors ◽  
Mass Ratio ◽  
Signal Flow Graph ◽  
Bond Graphs ◽  
Rotor Systems ◽  
Electromechanical Devices ◽  
Main Components

Electromechanical devices consist mainly of rotor systems. Vibration is the result of the interaction of the elements of the rotor system and is largely determined by the accuracy of manufacturing elements at the production stage and defects arising in the process of operation. The main components of the rotor systems that affect vibration are bearings. To determine the technical condition of the bearings and the service life of the rotor system, it is necessary to accurately measure the unobservable vibrations of the rotor. The article describes the model of the channel for measuring the vibration of an electromechanical system, built using the apparatus of bond graphs. The transfer function is obtained by analyzing the signal flow graph. The systematic and random errors of vibration measurement are analyzed depending on the mass ratio between the system case and the vibration transducer for various sensor masses and attachment rigidity.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

scholarly journals A computationally efficient hybrid 2D–3D subwoofer model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmad H. Bokhari ◽  
Martin Berggren ◽  
Daniel Noreland ◽  
Eddie Wadbro
Keyword(s):  
Hybrid Model ◽  
3D Model ◽  
Element Model ◽  
Acoustic Properties ◽  
Computational Time ◽  
Average Response ◽  
Frequency Range ◽  
Computationally Efficient ◽  
Lumped Element ◽  
Lumped Element Model

AbstractA subwoofer generates the lowest frequency range in loudspeaker systems. Subwoofers are used in audio systems for live concerts, movie theatres, home theatres, gaming consoles, cars, etc. During the last decades, numerical simulations have emerged as a cost- and time-efficient complement to traditional experiments in the design process of different products. The aim of this study is to reduce the computational time of simulating the average response for a given subwoofer design. To this end, we propose a hybrid 2D–3D model that reduces the computational time significantly compared to a full 3D model. The hybrid model describes the interaction between different subwoofer components as interacting modules whose acoustic properties can partly be pre-computed. This allows us to efficiently compute the performance of different subwoofer design layouts. The results of the hybrid model are validated against both a lumped element model and a full 3D model over a frequency band of interest. The hybrid model is found to be both accurate and computationally efficient.

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