Early Wear Fault Dynamics Analysis Method of Gear Coupled Rotor System Based On Dynamic Fractal Backlash

2021 ◽  
Author(s):  
Wujiu Pan ◽  
Liangyu Ling ◽  
Haoyong Qu ◽  
Minghai Wang
Keyword(s):  
Rotor System ◽  
System Model ◽  
Tooth Surface ◽  
System Response ◽  
Dynamics Analysis ◽  
Surface Wear ◽  
Analysis Method ◽  
Wear Model ◽  
Fault Dynamics ◽  
System Vibration

Abstract The aim of this paper is to establish a typical gear coupled rotor system model and give an analysis of the early wear of the tooth surface. The tooth surface wear will cause the change of the backlash. Different from previous studies on the backlash, the backlash in this paper is a dynamic fractal backlash, which is obtained based on the fractal wear model of the tooth surface. Firstly, based on the FA (Flodin and Andersson) model and our previous studies on the contact analysis of rough surfaces, a fractal wear model of tooth surface is established. Then, the system vibration response of embedded dynamic fractal backlash is compared with that of embedded fixed backlash. The results show that the traditional fixed backlash cannot reflect the small changes of the system response, while the dynamic fractal backlash can sensitively reflect changes of dynamic characteristics of the system, so this kind of mathematical model considering dynamic fractal wear will be more conducive to the analysis and prediction of gear wear faults in engineering.

Rotor System Mathematical Model Substructure-Based Reduction and Updating Using Experimental Modal Analysis

2018 ◽  
Author(s):  
Sergey Semenov ◽  
Mikhail Nikhamkin ◽  
Nikolai Sazhenkov
Keyword(s):  
Modal Analysis ◽  
Model Updating ◽  
Cost Effective ◽  
Rotor Dynamics ◽  
3D Scanning ◽  
Rotor System ◽  
Experimental Modal Analysis ◽  
System Model ◽  
Maintenance Cost ◽  
System Response

Modeling of rotor dynamics is one of the most important parts of gas turbine engine creation process. But the need to understand the system response to design predictable, low maintenance, cost-effective, and optimal systems has driven rotor dynamics to large-order complex rotor system models. These models contain more intricate geometric complexities, bearings, seals, and attached components such as disks, blades, fans, and couplings. All this makes vibration processes more complicated and so they require more calculation resources. That makes such iterative procedures as model updating and optimization difficult. Possible solution for this problem is substructuring. Partitioning of the model to substructures opens up a possibility to verify and update parts of the model independently using modern modal analysis experimental techniques like 3D scanning vibrometry. And then they can be condensed using reduction methods to simplify the whole model. This work demonstrates the possible way of rotor system model updating based on experimental modal analysis via 3D scanning vibrometry and reduction using CMS method. Demonstration of the method is made on a special rotor test rig. The quality of updating and reduction is evaluated by comparing of critical speeds obtained numerically and experimentally. The comparison shows that proposed method is adequate for rotor system model creation and simplification but for constructions with a lot of connections updating procedure should be improved.

The Influence of Tooth Surface Wear on Dynamic Characteristics of Gear-Bearing System Based on Fractal Theory

2020 ◽  
Vol 15 (4) ◽  
Author(s):  
Xiaopeng Li ◽  
Jinchi Xu ◽  
Zemin Yang ◽  
Renzhen Chen ◽  
Hexu Yang
Keyword(s):  
Dynamic Characteristics ◽  
Periodic Motion ◽  
Fractal Theory ◽  
Tooth Surface ◽  
System Response ◽  
Time Varying ◽  
Surface Wear ◽  
Meshing Stiffness ◽  
Motion State ◽  
Bearing System

Abstract In this paper, the influence of tooth surface wear on dynamic characteristics of the gear-bearing system is discussed. The gear-bearing system considering the factors of tooth surface friction, time-varying meshing stiffness, backlash and et al. is established. Based on the Fractal theory and the Archard theory, the tooth surface wear is calculated, and it is substituted into the calculation of backlash and stiffness to obtain the time-varying backlash and the time-varying meshing stiffness. The Runge–Kutta method is used to solve the dynamic differential equation of the gear system, then the phase diagrams, the Poincare section diagrams and the bifurcation diagrams of the system are obtained. The results show that compared with the constant backlash and normal-distribution backlash under the wear condition, the wear backlash calculated by the Fractal theory and the Archard theory can better show the influence of wear on the system response. With the increasing of the accumulated wear on the tooth surface, the decrement of the time-varying meshing stiffness increases, and the system is more unstable. As the friction coefficient decreases, the regions of periodic and quasi-periodic motion state increase, and the boundaries between the periodic and quasi-periodic motion state become clear. Therefore, friction mainly plays a hysteretic role on the gear-bearing system.

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.

A Rapid Analysis Method for Microgyroscope Using System Vibration Modes

2009 ◽  
Vol 60-61 ◽  
pp. 353-356
Author(s):  
Guang Jun Liu ◽  
An Lin Wang ◽  
Zi Yi Yu ◽  
Xing Yang ◽  
Tao Jiang
Keyword(s):  
Performance Analysis ◽  
Dynamic Response ◽  
Computing Time ◽  
State Space Model ◽  
Rapid Analysis ◽  
Vibration Modes ◽  
Analysis Method ◽  
Space Model ◽  
System Equation ◽  
System Vibration

This paper proposes a rapid dynamic analysis method for microgyroscope using system vibration modes to solve the problems concerning to the computing time in the performance analysis of microgyroscope. The results of eigenvalue solution are employed to construct the state space model. The response of the microgyros cope can be reconstructed as a response superposition of the vibration modes, and then the system equation is decoupled into an uncoupled equation. The dynamic response of the microgyroscope can be calculated by a simple superposition.

Vibration-based fault diagnosis of helical gear pair with tooth surface wear considering time-varying friction coefficient under mixed EHL condition

2021 ◽  
pp. 1-16
Author(s):  
Siyu Wang ◽  
Rupeng Zhu
Keyword(s):  
Dynamic Response ◽  
Hydrodynamic Lubrication ◽  
Helical Gear ◽  
Calculation Model ◽  
Tooth Surface ◽  
Time Varying ◽  
Gear Pair ◽  
Surface Wear ◽  
Mesh Stiffness ◽  
Helical Gear Pair

Abstract Based on “slice method”, the improved time-varying mesh stiffness (TVMS) calculation model of helical gear pair with tooth surface wear is proposed, in which the effect of friction force that obtained under mixed elasto-hydrodynamic lubrication (EHL) is considered in the model. Based on the improved TVMS calculation model, the dynamic model of helical gear system is established, then the influence of tooth wear parameters on the dynamic response is studied. The results illustrate that the varying reduction extents of mesh stiffness along tooth profile under tooth surface wear, in addition, the dynamic response in time-domain and frequency-domain present significant decline in amplitude under deteriorating wear condition.

scholarly journals Influence of radial clearance on nonlinear dynamics of a two-span three-support rotor system

2021 ◽  
Vol 233 ◽  
pp. 04012
Author(s):  
HE Xing ◽  
WU Yi-ming ◽  
LI Mo ◽  
ZENG Fan
Keyword(s):  
Periodic Motion ◽  
Rotor System ◽  
System Model ◽  
Radial Clearance ◽  
Structural Form ◽  
Single Cycle ◽  
Rolling Bearings ◽  
System A ◽  
Runge Kutta Method ◽  
Nonlinear Dynamic Characteristics

Aiming at the structural form of a certain rotor system, a double-span three-support rotor system model is established. It is supported by three rolling bearings and has a typical nonlinear characteristic. The fourth-order Runge-Kutta method is used to solve the differential equations and analyze the nonlinear dynamic characteristics of the rotor system when the radial clearance of the bearing changed. The research results: with the increase of the rear bearing radial clearance, the rotor system performs single cycle, periodic two and pseudo-periodic motion. With the three location bearing radial clearance increases, the rotor system performs single cycle, periodic two and periodic four motion. When the radial clearance is bigger, the rotor system performs two periodic motion. The influence law of radial clearance on double span three - braced rotor system is shown.

scholarly journals Dynamic characteristics of the gear-rotor system in compressed air energy storage considering friction effects

2021 ◽  
Vol 12 (1) ◽  
pp. 677-688
Author(s):  
Xinran Wang ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xingjian Dai ◽  
Haisheng Chen
Keyword(s):  
Energy Storage ◽  
Friction Coefficient ◽  
Dynamic Characteristics ◽  
Surface Friction ◽  
Rotor System ◽  
Compressed Air ◽  
Contact Temperature ◽  
Tooth Surface ◽  
Compressed Air Energy Storage ◽  
Rotating Speed

Abstract. The tooth surface friction effects and the resulting tooth surface contact temperature are important factors for the dynamic characteristics of a gear-rotor system in compressed air energy storage (CAES). Therefore, a 3∘ of freedom finite-element model of the system is set up in which the lubrication state of the gear pair, tooth surface friction, contact temperature of the tooth surface, backlash and unbalanced excitation are considered. The friction coefficient is calculated according to the variation of the lubrication state, and the tooth surface contact temperature is derived based on the friction coefficient. The tooth profile deformation caused by the change in the contact temperature is calculated, and the resulting effects on backlash and comprehensive meshing stiffness are considered. The influence of rotating speed, torque load and viscosity of lubricating oil on the system response is studied, and the variation of the friction coefficient, flash temperature of the tooth surface, pressure of the tooth surface and so on are discussed in detail. The results indicate that when the friction coefficient is derived according to the variation of the lubrication state, the variation of the contact temperature of the tooth surface with rotating speed is quite different from that calculated based on a friction coefficient which is set artificially. This leads to a new variation of the dynamic response of the gear-rotor system, and the method of stabilizing the operation of the system is put forward based on the optimization curve for the operation of the system. The results obtained in this paper will provide a reference for the study and design of a gear-rotor system in CAES.

Dynamic Behavior Analysis of Three-Span Rotor-Bearing System with Rub-Impact Fault

2012 ◽  
Vol 460 ◽  
pp. 160-164 ◽  
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Behavior Analysis ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Rotor System ◽  
System Response ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The dynamic model of the three-span rotor-bearing system with rub-impact fault was set up. The influence to nonlinear dynamics behaviors of the rotor-bearing system that induced by rub-impact of one disc, two discs and three discs were numerically studied. The main influence of the rotor system response by the rub-impact faults are in the supercritical rotate speed. There are mutations of amplitudes in the responses of second and third spans in supercritical rotate speed when rub-impact with one disc, and there are chaotic windows in the response of first span, and jumping changes in second and third spans when rub-impact with two or three discs.

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