Flaw detection method guided wave pulse compression with directional control properties and flaw detector

摘要

PROBLEM TO BE SOLVED: To remove noise and to increase incoming guide wave power by using a broadband waveform propagating in both directions, to provide a guide wave control technique for propagating it in one direction and an output waveform (pulse compression signal) suitable for flaw detection by selecting a guide wave from a specific direction, amplifying and extracting it, in a non-destructive flaw detection technique of detecting a defect of a structure using guide wave.;SOLUTION: By exciting transmitting sensors 6a and 6b with a predetermined time difference, a broadband guide wave 8 is controlled so as to propagate only in one direction, and transmitted. The waveform of the guide wave 10 reflected by a defect or the like is digitally recorded by receiving sensors 11a and 11b, time delay of each signal is corrected, and respective signals are added, thereby selectively amplifying and extracting only a received wave from the specific direction. A pulse compression technique of applying cross correlation operation is applied to the extracted signal by using an appropriate reference signal.;COPYRIGHT: (C)2007,JPO&INPIT