INFLUENCE OF A LEVELNESS DEFECT IN A THRUST BEARING ON THE DYNAMIC BEHAVIOUR OF AN ELASTIC SHAFT

2002 ◽  
Vol 249 (1) ◽  
pp. 41-53 ◽  
Author(s):  
S. BERGER ◽  
O. BONNEAU ◽  
J. FRÊNE
Keyword(s):  
Dynamic Behaviour ◽  
Thrust Bearing ◽  
Elastic Shaft

Influence of axial thrust bearing defects on the dynamic behavior of an elastic shaft

2000 ◽  
Vol 33 (3-4) ◽  
pp. 153-160 ◽  
Author(s):  
Sébastien Berger ◽  
Olivier Bonneau ◽  
Jean Frêne
Keyword(s):  
Dynamic Behavior ◽  
Thrust Bearing ◽  
Axial Thrust ◽  
Elastic Shaft ◽  
Bearing Defects

Dynamic Characteristics of Aerostatic Thrust Bearings with Porous Inserts

1980 ◽  
Vol 22 (2) ◽  
pp. 55-58 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Perturbation Method ◽  
Dynamic Characteristics ◽  
Dynamic Behaviour ◽  
Thrust Bearing ◽  
Thrust Bearings ◽  
First Order ◽  
Design Variables ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
First Order Perturbation

A first-order perturbation method is adopted to find the dynamic behaviour of an aerostatic circular thrust bearing having a central porous insert as a restrictor. The linearized gas film stiffness and damping are derived and used to study their behaviour with other design variables.

JET Flywheel Generators

1986 ◽  
Vol 200 (2) ◽  
pp. 95-100 ◽  
Author(s):  
M Huart ◽  
L Sonnerup
Keyword(s):  
Fatigue Life ◽  
Peak Power ◽  
Critical Speed ◽  
Dynamic Behaviour ◽  
Thrust Bearing ◽  
Mechanical Design ◽  
Vertical Shaft ◽  
Plasma Current ◽  
Design Life ◽  
Full Speed

Two large vertical shaft flywheel generators each provides the JET (Joint European Torus) device with peak power up to 400 MW and energy up to 2600 MJ per pulse to induce and confine the multi-mega-ampère plasma current. The integrated rotor flywheel consists of a 650 tonne/10 m diameter rim carrying the poles of the machine. The energy is stored kinetically during a 9 min interval of acceleration from half-speed to full-speed and then released during a 20 s long deceleration. A design life of 100 000 cycles at full energy rating was specified. Following a review of the mechanical design and construction of the generators, the paper will concentrate on the assessment of the stresses and fatigue life of the rotor system, its dynamic behaviour (rim movement, critical speed and balancing) and on the performance in operation of the large thrust bearing.

scholarly journals Dynamic Characteristics of Rotors on Passive and Active Thrust Fluid-film Bearings with Fixed Pads

2018 ◽  
Vol 148 ◽  
pp. 11003
Author(s):  
Alexander Babin ◽  
Leonid Savin ◽  
Sergey Majorov
Keyword(s):  
Pid Control ◽  
Dynamic Behaviour ◽  
Thrust Bearing ◽  
Position Control ◽  
Fluid Film ◽  
Operational Parameters ◽  
Test Rig ◽  
Fluid Film Bearings ◽  
Solution Of Equations ◽  
Tracking Condition

Application of fluid-film bearings in rotor machines in many cases could have no alternative due to obvious advantages when compared to roller element bearings. Integration of information technology in mechanical engineering resulting in emergence of a new field of research – mechatronic bearings which allowed tracking condition of the most important parts of a machine and adjusting operational parameters of the system. Application of servo valves to control the flow rate through a fluid-film bearing is the most universal and simple way of rotor’s position control due to relative simplicity of modelling and absence of need to radically change the design of conventional hydrodynamic bearings. In the present paper numerical simulations of passive (conventional as opposed to mechatronic) and active hybrid thrust fluid-film bearings with a central feeding chamber are presented, that are parts of a mechatronic rotor-bearing node. Numerical model of an active thrust bearing is based on solution of equations of hydrodynamics, rotor dynamics and an additional model of a servo valve. Various types of control have been investigated: P, PI and PID control, and the dynamic behaviour of a system has been estimated under various loads, namely static, periodic and impulse. A design of a test rig has been proposed to study passive and active thrust fluid-film bearings aimed at, among other, validation of numerical results of active bearings simulation.

Shaft mass effect on the dynamic behaviour of a rotor supported by fluid film bearings

2008 ◽  
Vol 222 (4) ◽  
pp. 643-651 ◽  
Author(s):  
K Alnefaie
Keyword(s):  
Electric Motor ◽  
Dynamic Behaviour ◽  
Mass Effect ◽  
Fluid Film ◽  
Mass Ratio ◽  
Motor Speed ◽  
Positive Real ◽  
Fluid Film Bearings ◽  
Elastic Shaft ◽  
Complex Roots

Shaft mass effect on the dynamic behaviour of a rotor supported by fluid film bearings is studied. The rotor is assumed as a thin disc located on the middle of an elastic shaft, which is supported by fluid film bearings. Non-zero elastic shaft mass is considered. The journal bearing is assumed as a short-plain type and it is represented by direct and cross-coupling stiffness and damping coefficients. These coefficients depend on the angular speed of the system. It is assumed that an electric motor accelerates the rotor. The electric motor speed is assumed to be controlled by a second-order transfer function. Simulation results show that for small values of mass ratio, which is defined as the ratio of the shaft mass to the disc mass, one pair of complex roots assumes positive real part for a range of rotor speeds and makes the system unstable. As the mass ratio increases, this pair of root becomes stable, but the other pair of complex roots assumes positive real parts and the system becomes unstable again. The system is always stable for subcritical run but unstable for some speed range for the supercritical run.

Investigation of fused silica dynamic behaviour

2006 ◽  
Vol 134 ◽  
pp. 929-934 ◽  
Author(s):  
F. Malaise ◽  
J.-M. Chevalier ◽  
I. Bertron ◽  
F. Malka
Keyword(s):  
Dynamic Behaviour ◽  
Fused Silica

A MODEL FOR THE FATIGUE SATURATION RANGE OF ALUMINIUM FROM DYNAMIC BEHAVIOUR AND INTERACTIONS OF DISLOCATIONS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-155-C8-160
Author(s):  
R. FOUGERES ◽  
J. CHICOIS ◽  
A. HAMEL ◽  
A. VINCENT
Keyword(s):  
Dynamic Behaviour

Analysis of the Multi-Channel Epileptiform EEG Using the Markov Chains Formalism

1989 ◽  
Vol 28 (03) ◽  
pp. 160-167 ◽  
Author(s):  
P. Penczek ◽  
W. Grochulski
Keyword(s):  
Dynamic Behaviour ◽  
Joint Probability ◽  
Drug Effects ◽  
Anticonvulsant Drug ◽  
Channel System ◽  
Markov Network ◽  
Eeg Data ◽  
Multi Level ◽  
Joint Probability Functions ◽  
Dependent State

Abstract:A multi-level scheme of syntactic reduction of the epileptiform EEG data is briefly discussed and the possibilities it opens up in describing the dynamic behaviour of a multi-channel system are indicated. A new algorithm for the inference of a Markov network from finite sets of sample symbol strings is introduced. Formulae for the time-dependent state occupation probabilities, as well as joint probability functions for pairs of channels, are given. An exemplary case of analysis in these terms, taken from an investigation of anticonvulsant drug effects on EEG seizure patterns, is presented.

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