Диагностика вибрационного состояния роторов двухконтурного турбореактивного двигателя с применением фазочастотной характеристики, полученной без использования датчика положения вала

2021 ◽  
pp. 25-34
Author(s):  
С.Л. Звонарев ◽  
А.И. Зубко ◽  
А.А. Зубко
Keyword(s):  
Phase Change ◽  
Phase Angle ◽  
Vibration Analysis ◽  
Initial Position ◽  
Phase Characteristic ◽  
Turbofan Engines ◽  
Stiffness And Damping ◽  
Frequency Phase

This paper considers theoretical and practical approaches to the construction of amplitude-frequency phase characteristics of turbofan engines and presents the results of the experiments. The novelty lies in excluding usage of information from the sensor of its initial position for the construction of the rotor phase characteristic. To determine the instantaneous value of the phase angle of the rotor oscillations, the method of orbital vibration analysis is used. Using the analysis of phase change of rotor fluctuation allows to define availability of resonance as well as defects and malfunctions that cause induce stiffness and damping of the rotor. Examples of turbofan engines diagnostics by means of the analysis of amplitude-frequency phase characteristics are given.

Frequency, Phase, and Colour Coding in Apparent Motion: 2

Perception ◽  
1979 ◽  
Vol 8 (5) ◽  
pp. 595-602 ◽  
Author(s):  
David Finlay ◽  
Terry Caelli
Keyword(s):  
Phase Angle ◽  
Apparent Motion ◽  
Temporal Frequency ◽  
Specific Inhibition ◽  
Original Stimulus ◽  
Critical Phase ◽  
Spatio Temporal ◽  
Colour Coding ◽  
Frequency Phase ◽  
Phase Relationships

In an earlier paper, Caelli and Finlay demonstrated that the perception of apparent motion was contingent on critical phase relationships between inducing sources, and their spatio-temporal frequency ranges. In their original stimulus red-green centre-surround sources were used and phase-specific inhibition was found at 60°–90° phase angle differences between the complementarily coloured elements. In this experiment we show that, when centre-surround sources are replaced by vertically-horizontally displaced complementary (or identically coloured) sources, symmetrical phase inhibition effects occur with both motions.

An Improved Design Method for Automotive Powertrain Rubber Mounts

2013 ◽  
Vol 853 ◽  
pp. 520-525 ◽  
Author(s):  
Min Lu
Keyword(s):  
Design Process ◽  
Phase Angle ◽  
Development Time ◽  
Design Method ◽  
Rubber Compound ◽  
Physical Test ◽  
Physical Testing ◽  
Automotive Powertrain ◽  
Improved Design ◽  
Stiffness And Damping

The objective of the powertrain mount design is to find the geometry which meets the desired stiffness and damping requirements. For the conventional rubber mount, which is composed of a rubber element bonded into a metal bracket, its stiffness can be predicted using FEA but the damping is evaluated by physical testing. This paper introduces a design method at which the damping coefficient of the rubber mount is to be predicted theoretically based on the assumption that the phase angle for a rubber compound is constant. Absence of physical test in this proposed new design process, the development time from concept to production is reduced.

Vibration Analysis of Statically Indeterminate Rotors With Hydrodynamic Bearings

1998 ◽  
Vol 120 (4) ◽  
pp. 781-788 ◽  
Author(s):  
N. S. Feng ◽  
E. J. Hahn
Keyword(s):  
Vibration Analysis ◽  
Operating Conditions ◽  
System Stability ◽  
Hydrodynamic Bearings ◽  
Hydrodynamic Bearing ◽  
Unbalance Response ◽  
Tilting Pad ◽  
The Stability ◽  
Rotor Bearings ◽  
Stiffness And Damping

In statically indeterminate rotor bearings systems, where the rotor is supported by one or more hydrodynamic bearings, the reactions at each hydrodynamic bearing, and hence its stiffness and damping properties depend not only on the bearing type, the operating conditions and the bearing dimensions but also on the relative lateral alignment between the journal and the bearing housing; the alignment, therefore, has a significant influence on the system stability and unbalance response. Additional complications arise if nonsymmetric bearing types such as elliptic or tilting pad bearings are present. An iterative procedure is outlined which enables the bearing reactions to be determined at any speed, thereby enabling even large systems such as turbomachinery to be rapidly analyzed in conjunction with existing linear rotor bearing vibration analysis software. Sample numerical examples show how misalignment and bearing type can affect the natural frequencies, the stability threshold, and the unbalance response of such statically indeterminate systems.

Reducing Vibration Analysis on Travel Stabilizing System of Wheel Loader Based on ProE and ADAMS

2011 ◽  
Vol 199-200 ◽  
pp. 839-844 ◽  
Author(s):  
Ge Ning Xu ◽  
Bing Wu
Keyword(s):  
Vibration Analysis ◽  
Influence Factor ◽  
Characteristic Parameter ◽  
Simulation Method ◽  
Equivalent Stiffness ◽  
Wheel Loader ◽  
Vibration Model ◽  
Stiffness And Damping

The mathematical vibration model of travel stabilizing system of wheel loader which was added to reduce spillage of material was built firstly. The equivalent stiffness and damping of travel stabilizing system were deduced, and influence factor was analyzed. In order to solver the characteristic parameter of the mathematical vibration model, the simulation method based on Pro/E and ADAMS was adopted. The result indicates selecting the appropriate parameter of accumulator is the important factor of the effect of travel stabilizing system. This paper is basic of further research on travel stabilizing system.

Binaural interaction in low-frequency neurons in inferior colliculus of the cat. II. Effects of changing rate and direction of interaural phase

1983 ◽  
Vol 50 (4) ◽  
pp. 1000-1019 ◽  
Author(s):  
T. C. Yin ◽  
S. Kuwada
Keyword(s):  
Phase Change ◽  
Inferior Colliculus ◽  
Phase Angle ◽  
Beat Frequency ◽  
Free Field ◽  
Rate Of Change ◽  
Phase Changes ◽  
Phase Sensitivity ◽  
Interaural Phase ◽  
The Mean

We used the binaural beat stimulus to study the interaural phase sensitivity of inferior colliculus (IC) neurons in the cat. The binaural beat, produced by delivering tones of slightly different frequencies to the two ears, generates continuous and graded changes in interaural phase. Over 90% of the cells that exhibit a sensitivity to changes in the interaural delay also show a sensitivity to interaural phase disparities with the binaural beat. Cells respond with a burst of impulses with each complete cycle of the beat frequency. The period histogram obtained by binning the poststimulus time histogram on the beat frequency gives a measure of the interaural phase sensitivity of the cell. In general, there is good correspondence in the shapes of the period histograms generated from binaural beats and the interaural phase curves derived from interaural delays and in the mean interaural phase angle calculated from them. The magnitude of the beat frequency determines the rate of change of interaural phase and the sign determines the direction of phase change. While most cells respond in a phase-locked manner up to beat frequencies of 10 Hz, there are some cells tht will phase lock up to 80 Hz. Beat frequency and mean interaural phase angle are linearly related for most cells. Most cells respond equally in the two directions of phase change and with different rates of change, at least up to 10 Hz. However, some IC cells exhibit marked sensitivity to the speed of phase change, either responding more vigorously at low beat frequencies or at high beat frequencies. In addition, other cells demonstrate a clear directional sensitivity. The cells that show sensitivity to the direction and speed of phase changes would be expected to demonstrate a sensitivity to moving sound sources in the free field. Changes in the mean interaural phase of the binaural beat period histograms are used to determine the effects of changes in average and interaural intensity on the phase sensitivity of the cells. The effects of both forms of intensity variation are continuously distributed. The binaural beat offers a number of advantages for studying the interaural phase sensitivity of binaural cells. The dynamic characteristics of the interaural phase can be varied so that the speed and direction of phase change are under direct control. The data can be obtained in a much more efficient manner, as the binaural beat is about 10 times faster in terms of data collection than the interaural delay.

THEORETICAL VIBRATION ANALYSIS OF SOFT MOUNTED TWO-POLE INDUCTION MOTORS WITH STATIC ROTOR ECCENTRICITY

2011 ◽  
Vol 03 (01) ◽  
pp. 131-159 ◽  
Author(s):  
ULRICH WERNER
Keyword(s):  
Vibration Analysis ◽  
Magnetic Force ◽  
Induction Motors ◽  
Rotor Speed ◽  
Electromagnetic Excitation ◽  
Worst Case ◽  
Rotor Eccentricity ◽  
Soft Foundation ◽  
Stiffness And Damping ◽  
Film Characteristics

The paper shows a mathematical model for vibration analysis of soft mounted two-pole induction motors regarding electromagnetic excitation due to static rotor eccentricity. A static rotor eccentricity causes an electromagnetic force, acting on the rotor and on the stator and oscillating with the double supply frequency. This magnetic force is implemented into a simplified analytical machine dynamic model and the correlations between the rotor dynamics, electromagnetic, oil film characteristics of the sleeve bearings, and the stiffness and damping of a soft foundation are mathematically described. The derived results are clarified using an example that shows the influence of the rotor speed and the direction of the magnetic force on the vibration behavior. On one hand the aim of the paper is to show the mathematical correlations, based on a simplified model. On the other hand, the aim is to derive a method for calculating the forced vibrations — as a worst case — caused by a static rotor eccentricity. Therefore, the paper shall prepare the basis for implementing this method in more detailed numerical programs, e.g., finite element programs.

Vibration analysis of a misaligned rotor—coupling—bearing system passing through the critical speed

2001 ◽  
Vol 215 (12) ◽  
pp. 1417-1428 ◽  
Author(s):  
S Prabhakar ◽  
A S Sekhar ◽  
A R Mohanty
Keyword(s):  
Transient Response ◽  
Vibration Analysis ◽  
Critical Speed ◽  
Rotor System ◽  
Continuous Wavelet ◽  
The Finite Element Method ◽  
System A ◽  
Different Types ◽  
Stiffness And Damping ◽  
Bearing System

The transient response of a misaligned rotor—coupling—bearing system passing through the critical speed has been analysed by using the finite element method (FEM) for flexural vibrations. The coupling has been modelled in two ways: a frictionless joint and a joint with stiffness and damping. From the vibration analysis, the subcritical speeds at one-half, one-third and one-fourth the critical speed have been found when the misaligned rotor—coupling—bearing system passes through its critical speed. The continuous wavelet transform (CWT) has been used as a tool to extract the silent features from the time response of the rotor system. A parametric study has been carried out to investigate the transient response of this rotor system for different angular accelerations in different types of misalignment.

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