ULTRASONIC PLANE SH WAVE REFLECTION FROM A UNI-DIRECTIONAL FIBROUS COMPOSITE SLAB
✍ Scribed by S.K. Bose
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 441 KB
- Volume
- 193
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
In the acoustic backscattering imaging method of ultrasonic non-destructive evaluation of composite laminates, the seemingly random amplitudes in a c-scan are most likely to be due to high frequency scattering by the large number of fibres with slightly changing positions, orientations and bonding characteristics along their length. To understand the phenomena, a multiple scattering theory, valid for all frequencies, has been developed for scalar SH waves reflected by an infinitely large number of uni-directional fibres enclosed in a slab region of an infinitely large body of matrix material. In view of the randomness in position of the fibres in a cross-section, the theory, correct to the order of c 2 , where c is the concentration of the fibres, ignores correlation in the positions of the fibres. Both coherent and incoherent scatterings are considered. A numerical example shows that resonance phenomena begin to appear at about the order of 0•1 MHz.