Publication:
Analysis, approach and assessment of vibration criteria in shipboard machinery condition monitoring and diagnostics

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Authors
Liu, Chao-Shih
Subjects
1/1 Octave Band Analysis
Alarm Level
Condition Monitoring and Diagnostics
Cross Peak Analysis
Fire Pump
Vibration
Advisors
Shin, Young S.
Date of Issue
1993-12
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The setting of alarm levels plays a vital role in a machinery condition monitoring and diagnostic system. In this research, two approaches to setting vibration alarm levels using vibration signals produced by fire pumps are presented in the time and frequency domains. In the time domain, the cross peak analysis (CPA) is proposed to extract the dominate peak points. The distribution of these cross peak points is found to have a lognormal distribution and can be normalized to a Normal distribution in the VdB domain. The computed microns + 2 Sigma value in the VdB domain is suggested for use as the alarm level. In the frequency domain, the 1/1 octave band analysis (OBA) is introduced. Three artificial fault simulations are conducted to compare the 1/1 octave band method with the broadband method. The results show that the 1/1 octave band method is more sensitive to the changes in VdB level than the broadband method. The computer programs to perform these two analyses are written using MATLAB. Examples of the use of these programs are included in this report
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
120 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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