Residual Unbalance Determination for Flexible Rotors at Operational Speed

2015 ◽  
pp. 757-768 ◽  
Author(s):  
Eric Knopf ◽  
Thomas Krüger ◽  
Rainer Nordmann
Keyword(s):  
Flexible Rotors

Secondary critical speed of flexible rotors with inertia slots

1983 ◽  
Vol 87 (1) ◽  
pp. 61-70 ◽  
Author(s):  
M. Sakata ◽  
M. Endo ◽  
K. Kishimoto ◽  
N. Hayashi
Keyword(s):  
Critical Speed ◽  
Flexible Rotors

Optimized Design of Vibration Controllers for Steady and Transient Excitation of Flexible Rotors

1995 ◽  
Vol 209 (3) ◽  
pp. 155-168 ◽  
Author(s):  
P S Keogh ◽  
C Mu ◽  
C R Burrows
Keyword(s):  
Measurement Error ◽  
Controller Design ◽  
Optimized Design ◽  
Rotor Vibration ◽  
Transient Vibration ◽  
Flexible Rotors ◽  
Vibration Attenuation ◽  
Measured Displacement ◽  
Control Forces ◽  
Shaft Surface

Controller designs for the attenuation of rotor vibration are investigated. Disturbance inputs leading to vibration are classified and related to control forces and defined control states. Optimization based on the H∞ norm is then used to minimize the influence of forcing disturbances, modelling error and measurement error. The practicalities of applying the method to an experimental rotor-bearing system, with hardware constraints on controller order, are stated. The controller was implemented experimentally to conduct steady state and mass loss tests. Steady synchronous, non-synchronous and transient vibration attenuation was demonstrated. It was also shown that measurement error, caused by shaft surface roughness, can be incorporated into the controller design without the need to remove the roughness component from the measured displacement signals. If the roughness influence is not included in the design and the uncontrolled vibration is small, unnecessary control forces may result, causing an increase in vibration.

THE OPTIMIZATION TECHNIQUE-BASED BALANCING OF FLEXIBLE ROTORS WITHOUT TEST RUNS

2000 ◽  
Vol 238 (5) ◽  
pp. 877-892 ◽  
Author(s):  
B. XU ◽  
L. QU ◽  
R. SUN
Keyword(s):  
Optimization Technique ◽  
Flexible Rotors

Nonlinear Dynamics of Flexible Rotors Supported on Journal Bearings—Part I: Analytical Bearing Model

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Mohammad Miraskari ◽  
Farzad Hemmati ◽  
Mohamed S. Gadala
Keyword(s):  
Journal Bearing ◽  
Nonlinear Coefficient ◽  
Journal Bearings ◽  
Flexible Rotor ◽  
Dynamic Coefficients ◽  
Flexible Rotors ◽  
Rotor Bearing ◽  
Bearing Force ◽  
Derivatives Of ◽  
Bearing System

To determine the bifurcation types in a rotor-bearing system, it is required to find higher order derivatives of the bearing forces with respect to journal velocity and position. As closed-form expressions for journal bearing force are not generally available, Hopf bifurcation studies of rotor-bearing systems have been limited to simple geometries and cavitation models. To solve this problem, an alternative nonlinear coefficient-based method for representing the bearing force is presented in this study. A flexible rotor-bearing system is presented for which bearing force is modeled with linear and nonlinear dynamic coefficients. The proposed nonlinear coefficient-based model was found to be successful in predicting the bifurcation types of the system as well as predicting the system dynamics and trajectories at spin speeds below and above the threshold speed of instability.

scholarly journals Uncertainty analysis of flexible rotors considering fuzzy parameters and fuzzy-random parameters

2015 ◽  
Vol 12 (10) ◽  
pp. 1807-1823 ◽  
Author(s):  
Fabian Andres Lara-Molina ◽  
Edson Hideki Koroishi ◽  
Valder Steffen Jr
Keyword(s):  
Uncertainty Analysis ◽  
Random Parameters ◽  
Flexible Rotors ◽  
Fuzzy Parameters ◽  
Fuzzy Random
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