FREQUENCY RESPONSE TESTING AT HIGH FREQUENCY IN A NOISY ENVIRONMENT WITH PARTICULAR REFERENCE TO CONDITION MONITORING
During high frequency vibration testing, many problems may be encountered which are not found at lower frequencies. Excitation and measurement systems are working under conditions where their operation is governed by upper and lower frequency limits. If tests are carried out through a wide frequency range using the transient testing technique, the dynamic range between the peak signals measured at resonance and the smaller signals off resonance may cause problems. Signal-to-noise ratios may be poor, either because the structure under test is large and the excitation force small, or because in a heavily-damped structure the response may be generally small. In the work reported here, the linear swept sinewave transient excitation method is applied to both simple and more typical test structures, and techniques for signal-to-noise ratio improvement are investigated. The improvement in accuracy of transient data using ensemble averaging is found to be governed by the timebase stability of the excitation signal and frequency resolution. Finally, the Report describes experiments with a method of signal generation by inverse transformation. This enables signals from components within a machine to be related to the exciting force by means of transfer functions.
Southampton University, EnglandInstitute of Sound and Vibration Research
Southampton S09 5NH, Hampshire, England
- White, M F
- Publication Date: 1976-4
- Features: References;
- Pagination: 106 p.
- TRT Terms: Machinery; Monitoring; Technology; Vibration; Vibrometers
- Uncontrolled Terms: Condition monitoring
- Old TRIS Terms: Machinery vibration; Vibration measurement
- Subject Areas: Marine Transportation; Vehicles and Equipment;
- Accession Number: 00149550
- Record Type: Publication
- Source Agency: British Ship Research Association
- Report/Paper Numbers: No. 84 Tech. Rpt.
- Files: TRIS
- Created Date: Apr 13 1977 12:00AM