Method of conducting probe coupling calibration in a guided-wave inspection instrument

摘要

The method for calibrating an inspection instrument coupled with acoustic transducers disposed at circumferential positions distributed around a surface of an elongated object to inspect generally has the steps of: for each one of the circumferential positions, measuring a first and a second received signal using two acoustic transducers disposed at two axial positions along the object, the received signals resulting from the propagation of an acoustic guided wave signal along the object; identifying an acoustic mode according to the first received and the second received signals using a known period of time associated with the propagation of the acoustic guided wave signal between the two axial positions along the object; and determining a coupling coefficient associated with the acoustic mode, the coupling coefficient being indicative of the coupling of the acoustic transducers on the object; and calibrating the inspection instrument coupled to the object based on the coupling coefficients.

主权项

1. A method for calibrating an inspection instrument coupled with a plurality of acoustic transducers disposed at a plurality of circumferential positions distributed on a test surface of an elongated test object to be inspected, each of the acoustic transducers is acoustically coupled with the test surface during operation, the method comprising the steps of:
for each one or one group of the plurality of circumferential positions,
measuring at least a first and a second received signal using at least two or two groups of acoustic transducers disposed at two distinct axial positions along the elongated test object, the received signals resulting from the propagation of an acoustic guided wave signal along the elongated test object;identifying an acoustic mode according to the first received and the second received signals using a known period of time associated with the propagation of the acoustic guided wave signal between the two axial positions along the elongated test object; anddetermining a coupling coefficient associated with the acoustic mode, the coupling coefficient being indicative of the relative coupling condition between at least one of the at least two or two groups acoustic transducers and the elongated test object; and, calibrating the inspection instrument for the at least one of the at least two or two groups of acoustic transducers based on the plurality of coupling coefficients.