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Design of a self-calibrating simulated acoustic emission source
M J Evans1, J R Webster, P Cawley
1Department of Mechanical Engineering, Imperial College, London, UK.
Ultrasonics
|March 13, 2001
Summary
Conical piezoelectric transducers serve as effective point acoustic sources for acoustic emission measurements. Their backing response can assess coupling efficiency, improving calibration accuracy in structural health monitoring.
Area of Science:
- Acoustics
- Materials Science
- Metrology
Background:
- Acoustic emission (AE) measurements are crucial for structural health monitoring.
- Accurate calibration of AE systems requires reliable point acoustic sources.
- Conical piezoelectric transducers offer potential as standardized acoustic sources.
Purpose of the Study:
- To investigate the suitability of conical piezoelectric transducers as point acoustic sources for AE measurements.
- To evaluate the use of transducer backing response for assessing coupling efficiency.
- To explore methods for improving the accuracy of AE calibration experiments.
Main Methods:
- Utilized conical piezoelectric transducers based on a National Institute for Standards and Technology (NIST) design.
- Tested transducers as point transmitters within the 100 kHz to 1 MHz frequency range.
- Measured the response of the transducer backing to assess coupling variations.
Main Results:
- Conical piezoelectric transducers function effectively as point transmitters in the relevant AE frequency range.
- Transducer backing response measurements correlate with coupling efficiency.
- Observed shifts in resonance frequencies due to mechanical load impedance explain coupling effects.
Conclusions:
- NIST-designed conical piezoelectric transducers are suitable for AE source calibration.
- Backing response monitoring offers a method to quantify and correct for coupling variations.
- This technique could be extended to assess coupling in standard AE and ultrasonic transducers.