A technique for experimental identification of the substructures of a rotor system mathematical model for vibration diagnostics

2020 ◽  
Author(s):  
S. V. Semenov ◽  
M. Sh. Nikhamkin ◽  
N. A. Sazhenkov ◽  
A. A. Balakirev
Keyword(s):  
Mathematical Model ◽  
Rotor System ◽  
Vibration Diagnostics ◽  
Experimental Identification

Influence Characteristics of Fluid Film Bearing’s Displacement-Load on Rotating Vibration of Rotor System

2015 ◽  
Vol 727-728 ◽  
pp. 567-571
Author(s):  
Xi Chen Lin ◽  
Rui Ping Zhou ◽  
Neng Qi Xiao
Keyword(s):  
Mathematical Model ◽  
Numerical Integration ◽  
Dynamic Characteristics ◽  
Load Distribution ◽  
High Load ◽  
Rotor System ◽  
Vibration Response ◽  
Fluid Film ◽  
Load Carrying

In high load-carrying bearing-rotor system, bearings’ places usually change for load distribution or in continual work. It influences the system’s stability, and brings out different vibration response in rotor system. This article puts forward mathematical model of bearing’s stiffness under load which is calculated from bearing displacement. Then through numerical integration it studies system’s rotating vibration with different bearing settings. The results of the analysis show that bearing displacement has a great effect on dynamic characteristics of the bearing-rotor system.

scholarly journals The Influence of Slowly Varying Mass on Severity of Dynamics Nonlinearity of Bearing-Rotor Systems with Pedestal Looseness

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Mian Jiang ◽  
Jigang Wu ◽  
Shuangqi Liu
Keyword(s):  
Mathematical Model ◽  
Control Parameter ◽  
Rotor System ◽  
Cosine Function ◽  
Nonlinear Mathematical Model ◽  
Rotor Systems ◽  
Disk Mass ◽  
Amplitude Coefficient ◽  
Varying Mass

Nonlinearity measure is proposed to investigate the influence of slowly varying mass on severity of dynamics nonlinearity of bearing-rotor systems with pedestal looseness. A nonlinear mathematical model including the effect of slowly varying disk mass is developed for a bearing-rotor system with pedestal looseness. The varying of equivalent disk mass is described by a cosine function, and the amplitude coefficient is used as a control parameter. Then, nonlinearity measure is employed to quantify the severity of dynamics nonlinearity of bearing-rotor systems. With the increasing of looseness clearances, the curves that denote the trend of nonlinearity degree are plotted for each amplitude coefficient of mass varying. It can be concluded that larger amplitude coefficients of the disk mass varying will have more influence on the severity of dynamics nonlinearity and generation of chaotic behaviors in rotor systems with pedestal looseness.

Study on the Dynamics of a Rotor in a Maneuvering Aircraft

2003 ◽  
Vol 125 (3) ◽  
pp. 324-327 ◽  
Author(s):  
Fusheng Lin ◽  
Guang Meng
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Vertical Plane ◽  
Angular Speed ◽  
Rotor System ◽  
Flight Path ◽  
Constant Acceleration ◽  
Unbalanced Rotor ◽  
The Mathematical Model

This paper shows how the dynamics of a rotor in a maneuvering aircraft changes according to the operation of the aircraft. The mathematical model of an unbalanced rotor system located in the maneuvering aircraft is derived. The dynamic characteristics of the rotor running at a constant angular speed or a constant acceleration are studied under the assumptions that the aircraft maneuvers only in a vertical plane and that the pitching angle and the flight path inclination of the aircraft are equal. The effects of gravity and unbalance parameter are considered. The results show that the unbalanced response of a rotor in an aircraft is obviously influenced by the aircraft’s flying status.

scholarly journals Research on Nonlinear Dynamic Characteristics and Stability of Aerodynamic Bearings

2014 ◽  
Vol 8 (1) ◽  
pp. 243-250 ◽  
Author(s):  
Jia Chen-Hui ◽  
Du Cai-Feng ◽  
Qiu Ming
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Rotor System ◽  
Eccentricity Ratio ◽  
Nonlinear Dynamic Characteristics ◽  
Stiffness And Damping Coefficient ◽  
Reasonable Choice ◽  
The Stability ◽  
Perturbation Pressure ◽  
Stiffness And Damping

In order to research the conical spiral groove aerodynamic bearings, the lubrication mathematical model of the bearings was established. The Reynolds equation of the laminar flow condition is used to calculate the partial differential equation of the perturbation pressure with the local finite difference method. Through calculating the stiffness and damping coefficient, the influence of the speed of law and eccentricity ratio on the dynamic characteristic coefficients has been gained. The mathematical model for the stability of the bearing-rotor system is established to study the influence law of speed influence of the law of speed and eccentricity ratio on the stability. The results show that the influence of the bearing's speed and eccentricity on the dynamic characteristics is significant. A reasonable choice of the bearing's speed and eccentricity contributes to improve the dynamic characteristics and the stability of the bearing-rotor system.

scholarly journals Shafting Alignment Computing Method of New Multibearing Rotor System under Specific Installation Requirement

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Qian Chen ◽  
Qi Yuan ◽  
Ming Lei ◽  
Mengyao Wang
Keyword(s):  
Mathematical Model ◽  
Steam Turbine ◽  
Bending Moment ◽  
Moment Equation ◽  
Rotor System ◽  
Turbine Generator ◽  
Calculation Results ◽  
Computing Method

The shafting of large steam turbine generator set is composed of several rotors which are connected by couplings. The computing method of shafting with different structure under specific installation requirement is studied in this paper. Based on three-moment equation, shafting alignment mathematical model is established. The computing method of bearing elevations and loads under corresponding installation requirements, where bending moment of each coupling is zero and there exist preset sag and gap in some couplings, is proposed, respectively. Bearing elevations and loads of shafting with different structure under specific installation requirement are calculated; calculation results are compared with installation data measured on site which verifies the validity and accuracy of the proposed shafting alignment computing method. The above work provides a reliable approach to analyze shafting alignment and could guide installation on site.

Optimal Control of the Rotor System Motion

2013 ◽  
Vol 705 ◽  
pp. 546-552
Author(s):  
Imankul Toleukhan
Keyword(s):  
Mathematical Model ◽  
Optimal Control ◽  
Electric Drive ◽  
Rotor System ◽  
Flexible Shaft ◽  
Experimental Works ◽  
Set Up ◽  
Automatic Balancing ◽  
The Mathematical Model

Among the problems of the rotor machines dynamics the special attention is given to the problems of creation of the automatic balancing devices (ABD) in form of a hollow rotor, filled by a liquid, and the liquid-solidbody ABD. The theoretical and experimental works on research of the ABD on the base of a hollow rotor filled partially with a liquid and of the liquid-solidbody ABD are not enough. Therefore development of the methods of research of dynamics of the rotor machines with the ABD and such machines designs is an actual, new and perspective problem. In the present work the mathematical model of the rotor system with the ABD taking into account of the engine characteristics is offered. Lets consider the model of the rotor with electric drive with one disk, set up at the flexible shaft without skew. The shaft is lean on two bearings (fig. 1).

Modeling and Simulation of a Hydroelectric Process

2015 ◽  
Vol 811 ◽  
pp. 133-141 ◽  
Author(s):  
Vlad Mureşan ◽  
Mihail Abrudean ◽  
Tiberiu Colosi ◽  
Cristian Bondici ◽  
Iulia Clitan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Modeling And Simulation ◽  
Technological Process ◽  
Model Simulation ◽  
Hydroelectric Power Plant ◽  
Synchronous Generator ◽  
Hydroelectric Power ◽  
Experimental Identification ◽  
Identification Procedures

In this paper, a solution for the mathematical modeling and simulation of the technological process associated to a turbine – synchronous generator group, belonging to a small hydroelectric power plant. In order to determine the parameters of the treated technological process, some experimental identification procedures are applied. The experimental identification procedures are applied to the experimental data obtained from the real plant. The validity of the obtained mathematical model is proved through the comparison of the experimental data with the data obtained after the model simulation. The technological importance of having a valid mathematical model of the hydroelectric process consists in the possibility to study the plant behavior for different working regimes using the results of the model simulation and in the possibility of including the process in an automatic control structure.

scholarly journals Effect of asymmetries of stiffness and mass on parametric instabilities of hollow rotor system

2021 ◽  
Author(s):  
Sandeep Chauhan ◽  
◽  
Chandan Kumar ◽  
Ashish Gupta ◽  
Vikas Rastogi ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Simulation Study ◽  
Analytical Study ◽  
Rotor System ◽  
Hamiltonian Approach ◽  
Bond Graphs ◽  
First Case ◽  
Parametric Instabilities ◽  
Good Agreement

The present work aims to understand the influence of the asymmetries on the dynamics of the hollow rotor system. The study comprises the analytical study through the extended Lagrangian Hamiltonian approach and validation conducted with the simulation study through the bond graphs. This study involves an investigation of the dynamics of the hollow rotor system through two case studies. First case study considers a hollow rotor system with small asymmetry in stiffness while another study considers a hollow rotor system with asymmetry in mass. The lumped analysis involves the development of a mathematical model by considering the symmetry breaking of a hollow rotor caused by mass or stiffness. The study shows good agreement in simulation and analytical results.

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