Measuring and testing – Instrument proving or calibrating – Apparatus for measuring by use of vibration or apparatus for...
Patent
1997-10-23
1999-07-27
Williams, Hezron
Measuring and testing
Instrument proving or calibrating
Apparatus for measuring by use of vibration or apparatus for...
73587, G01N 2914
Patent
active
059293152
ABSTRACT:
A method and an apparatus for detecting and measuring cracks in plate-like structures using acoustic emission technique are disclosed. A false aperture transducer is designed to provide a criterion for filtering out extraneous noise in the acoustic emission signal based on modal analysis by computing the ratio of the high-frequency peak amplitude to low-frequency peak amplitude of the signal. A calibration curve correlating crack depth to the amplitude ratio can be obtained by simulating crack growth in a fracture specimen coupled to a test structure or field structure, and measuring acoustic emission signal in the structure by the false aperture transducer. The calibration curve correlates simulated crack depth percentage with computed peak amplitude ratio of the measured signal. Using the calibration curve and acoustic emission signal sensed by a false aperture transducer in a field structure, a crack in the structure can be detected and its depth measured by computing the peak amplitude ratio of the signal and identifying the crack depth that correlates with the ratio from the calibration curve.
REFERENCES:
patent: 3566163 (1971-02-01), Fischer et al.
patent: 4011472 (1977-03-01), Feng
patent: 4039767 (1977-08-01), Leschek
patent: 4064735 (1977-12-01), Hutchison et al.
patent: 4088907 (1978-05-01), Jones et al.
patent: 4353255 (1982-10-01), Fukuda et al.
patent: 5029474 (1991-07-01), Schulze
patent: 5101162 (1992-03-01), Webster et al.
patent: 5191558 (1993-03-01), Gorman et al.
patent: 5251469 (1993-10-01), Chan
"Non-Destructive Characterization of Hydrogen-Embrittlement Cracking by Acoustic Emission Techniques": H.L. Dunegan and A.S. Tetelman; Engineering Fracture Mechanics, vol. 2., pp. 387-402 (1971).
"AE Source Orientation by Plate Wave Analysis"; Michael R. Gorman and William H. Prosser; Journal of Acoustic Emission. vol. 9, No. 4, pp. 283-288 (1991).
"Plate Wave Acoustic Emission"; Michael R. Gorman; J. Acoustics Society of America (Jul. 1991).
"Relating Acoustic Emission Theory to Practice"; Michael R. Gorman; International Advances in Nondestructive Testing; Warren McGonnogle, Editor; Gordon and Breach, Publisher; vol. 17, p. 287 (1992).
"Experimental Far-Field Widebank Acoustic Waves in Wood Rods and Plates"; M.A. Hamstad et al.; Proceedings of the 9th International Symposium on Nondestructive Testing of Wood; Conferences & Institutes, Washington State University (1994).
"Accurate Simulation of Acoustic Emission Sources in composite Plates"; W.H. Prosser and M.R. Gorman; 1994 ASN Spring Conference (1994).
"The DECI Report"; H. L. Dunegan (Jun. 1995).
"The Use of Plate Wave Analysis in Acoustic Emission Testing to Detect and Measure Crack Growth in Noisy Environments"; H.L. Dunegan; 1996 Structural Materials Technology NDE Conference (1996).
"Invention Description" by William H. Prosser and Michael R. Gorman, Aug., 1993 and Sep.,1993.
Miller Rose M.
Williams Hezron
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