Study of Nondestructive Evaluation Methods for Layered Structures.
Abstract
Acoustic parameters of adhesively bonded layered structures were extracted from experimental cw spectra. Computer software was developed which yielded the best fit of the experimental spectra of such structures to theoretical spectra generated from the theoretical model of layered structures. The acoustic parameters for such a fit then corresponded to the structures under study. A sampled cw Doppler-effect technique was developed to measure radial bolt-hole cracks under the fasteners in single- and multi-layered adhesively bonded structures. This technique measures the size of the cracks far more accurately than any of the previously used amplitude or time delay methods. An Ultrasonic Pseudorandom-Signal-Correlation System was designed, fabricated, and experimentally characterized. This type of instrument may be useful in applications where high signal-to-noise ratios are not obtainable by conventional methods. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1979
- Accession Number
- ADA080969
Entities
People
- C. M. Elias
- J. S. Leffler
- N. K. Batra