Methods and apparatus for extracting first arrival wave packets in a structural health monitoring system
US7946176B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2008 |
| Grant date | May 24, 2011 |
| Priority date | — |
| Expiry date | Oct 10, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/106
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus for extracting the first arrival wave packet of an acoustic signal in a structural health monitoring (SHM) system include receiving an acoustic signal transmitted between two transducers thereof. Electromagnetic cross-talk is removed from the signal. Signal amplitude threshold values used for picking out the first arrival wave packet are chosen based on signal characteristics or chosen adaptively as the value that leads to the minimum variance of the group velocity estimates of all the actuation-sensing transducer pairs. The group velocity is estimated as the known actuator-sensor distance divided by the propagation time of the first wave packet of which the envelope exceeds a candidate threshold value. The first arrival wave packet is determined as the signal segment where the signal envelope first exceeds the chosen amplitude threshold and the segment length exceeds a specified threshold of time width.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.