Inventors:
Hubert B. Davis - Tucker GA
Bonner W. Staff - Acworth GA
James A. Willis - Smyrna GA
Assignee:
Lockheed Corporation - Burbank CA
International Classification:
G01N 2782
G01R 3312
G05B 1902
Abstract:
An automated eddy current fastener hole inspection apparatus and method for providing an automatic indication of the presence of a crack in structural members. The device automatically advances the probe of an eddy current instrument in a hole in the structural member, induces an eddy current, detects the eddy current signal produced by the eddy current instrument, digitizes the eddy current signal, analyzes the digitized signal for the presence of a characteristic signature corresponding to the effect of a crack in the structural member upon the eddy current signal, and alerts the operator of the presence of a crack or of noise conditions in the eddy current signal which may mask the presence of a crack. The device is responsive to contiguous repetitions of the characteristic signature of a crack within predetermined time windows to distinguish between data corresponding to a bona fide crack in the structural member from data produced by the effect of noise, dirt, grease, etc. upon the eddy current signal.