Investigating Vibration Sources of Faulty Gear Units

2008 ◽  
Vol 385-387 ◽  
pp. 601-604
Author(s):  
Ales Belsak ◽  
Joze Flasker
Keyword(s):  
Signal Analysis ◽  
Analysis Tool ◽  
Tooth Root ◽  
Dynamic Parameters ◽  
Unit Operation ◽  
Time Frequency ◽  
Tooth Stiffness ◽  
Non Stationary Signal ◽  
High Degree ◽  
Very High

A crack in the tooth root is the least desirable damage of gear units, which often leads to failure of gear unit operation. A possible damage can be identified by monitoring vibrations. The influences that a crack in the tooth root of a single-stage gear unit has upon vibrations are dealt with. Changes in tooth stiffness are much more expressed in relation to a fatigue crack in the tooth root, whereas in relation to other faults, changes of other dynamic parameters are more expressed. Signal analysis has been performed in relation to a non-stationary signal, by means of the Time Frequency Analysis tool, such as Wavelets. Typical scalogram patterns resulting from reactions to faults or damages indicate the presence of faults or damages with a very high degree of reliability.

Investigating Faulty Gear-Unit Vibration

2010 ◽  
Vol 452-453 ◽  
pp. 429-432
Author(s):  
Aleš Belšak ◽  
Jože Flašker
Keyword(s):  
Fatigue Crack ◽  
Wavelet Function ◽  
Operating Conditions ◽  
Tooth Root ◽  
Dynamic Parameters ◽  
Unit Operation ◽  
Dynamic Reaction ◽  
Time Frequency ◽  
Tooth Stiffness ◽  
Non Stationary Signal

A crack in the tooth root is probably the least desirable problem in gear unit operation; it often leads to failure. Signals produced by a gear with a crack in the tooth root, produced through real operating conditions, and signals caused by a faultless gear are used for the analysis. By monitoring vibrations it is possible to detect the presence of a crack. A fatigue crack in the tooth root brings about significant changes in tooth stiffness. Other faults are usually linked with modifications of other dynamic parameters. Time Frequency Analysis tools, e.g. Wavelets Analyses, are used to analyse a non-stationary signal. The wavelet transform is chosen for the analysis. The wavelet function similar to the dynamic reaction of the crack in the tooth root is selected. By means of the methods and the analysis presented in this paper, the reliability of determining modifications in signal vibrations is improved.

Crack Identification in Gear Tooth Root Using Adaptive Analysis

2007 ◽  
Vol 348-349 ◽  
pp. 697-700
Author(s):  
Ales Belsak ◽  
Jože Flašker
Keyword(s):  
Fatigue Crack ◽  
Signal Analysis ◽  
Gear Tooth ◽  
Crack Identification ◽  
Test Plant ◽  
Tooth Root ◽  
Dynamic Parameters ◽  
Unit Operation ◽  
Tooth Stiffness ◽  
Non Stationary Signal

Problems concerning gear unit operation can result from various typical damages and faults. A crack in the tooth root, which often leads to failure in gear unit operation, is the most undesirable damage caused to gear units. This article deals with fault analyses of gear units with real damages. A laboratory test plant has been prepared; it has been possible to identify certain damages by monitoring vibrations. In concern to a fatigue crack in the tooth root significant changes in tooth stiffness are more expressed. When other faults are present, however, other dynamic parameters prevail. Signal analysis has been performed also in concern to a non-stationary signal, using the adaptive transformation for signal analysis.

Vibration Analysis of Gears with Fatigue Crack in Tooth Root

2006 ◽  
Vol 324-325 ◽  
pp. 835-838
Author(s):  
Aleš Belšak ◽  
Jože Flašker
Keyword(s):  
Fatigue Crack ◽  
Laboratory Test ◽  
Signal Analysis ◽  
Vibration Analysis ◽  
Operating Conditions ◽  
Test Plant ◽  
Tooth Root ◽  
Unit Operation ◽  
Time Frequency ◽  
Non Stationary Signal

A crack in the tooth root, which often leads to failure in gear unit operation, is the most undesirable damage caused to gear units. This article deals with fault analyses of gear units with real damages. Numerical simulations of real operating conditions have been used in relation to the formation of those damages. A laboratory test plant has been used and a possible damage can be identified by monitoring vibrations. The influences of defects of a single-stage gear unit upon the vibrations they produce are presented. Signal analysis has been performed also in concern to a non-stationary signal, using the Time Frequency Analysis tools. Typical spectrograms, which are the result of reactions to damages, are a very reliable indication of the presence of damages.

CQPweb — combining power, flexibility and usability in a corpus analysis tool

2012 ◽  
Vol 17 (3) ◽  
pp. 380-409 ◽  
Author(s):  
Andrew Hardie
Keyword(s):  
Data Model ◽  
Ease Of Use ◽  
Corpus Analysis ◽  
Analysis Tool ◽  
Analysis Software ◽  
Web Based ◽  
Query System ◽  
Analysis System ◽  
High Degree ◽  
Very High

CQPweb is a new web-based corpus analysis system, intended to address the conflicting requirements for usability and power in corpus analysis software. To do this, its user interface emulates the BNCweb system. Like BNCweb, CQPweb is built on two separate query technologies: the IMS Open Corpus Workbench and the MySQL relational database. CQPweb’s main innovative feature is its flexibility; its more generalised data model makes it compatible with any corpus. The analysis options available in CQPweb include: concordancing; collocations; distribution tables and charts; frequency lists; and keywords or key tags. An evaluation of CQPweb against criteria earlier laid down for a future web-based corpus analysis tool suggests that it fulfils many, but not all, of the requirements foreseen for such a piece of software. Despite some limitations, in making a sophisticated query system accessible to untrained users, CQPweb combines ease of use, power and flexibility to a very high degree.

Non-Stationary Signal Analysis Based on Hilbert-Huang Transform and Median Filter

2014 ◽  
Vol 1049-1050 ◽  
pp. 1694-1697
Author(s):  
Xiao Li Wang ◽  
Dian Hong Wang
Keyword(s):  
White Noise ◽  
Frequency Analysis ◽  
Signal Analysis ◽  
Median Filter ◽  
Low Noise ◽  
Analytic Framework ◽  
Noise Resistance ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Non Stationary Signal

The Hilbert-Huang Transform (HHT) is a new time-frequency analysis with adaptability and orthogonality, but it is rather weak in terms of noise resistance, even low noise can disturb the HHT result greatly. The paper launches an investigation on how noises affect the HHT result and proposes the method to solve the problem. The analytic framework for HHT is first introduced, the feature of the test signal is extracted by HHT. Median filter is adopted to reduce the frequency leakage of certain signal component caused by white noise. The method proposed is experimentally simulated and the results demonstrate its effectiveness.

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