Method for improving defect detectability with magnetostrictive sensors for piping inspection
US6205859A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1999 |
| Grant date | Mar 27, 2001 |
| Priority date | — |
| Expiry date | Jan 11, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2634
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved method for defect detection with systems using magnetostrictive sensor techniques. The improved method involves exciting the magnetostrictive sensor transmitter by using a relatively broadband signal instead of a narrow band signal typically employed in existing procedures in order to avoid signal dispersion effects. The signal detected by the magnetostrictive sensor receiver is amplified with an equally broadband signal amplifier. The amplified signal is transformed using a time-frequency transformation technique such as a short-time Fourier transform. Finally, the signal characteristics associated with defects and anomalies of interest are distinguished from extraneous signal components associated with known wave propagation characteristics. The process of distinguishing defects is accomplished by identifying patterns in the transformed data that are specifically oriented with respect to the frequency axis for the plotted signal data. These identified patterns correspond to signals from either defects or from known geometric features in the pipe such as welds or junctions. The method takes advantage of a priori knowledge of detected signal characteristics associated w…
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