Ultrasonic Rayleigh wave

G. C. Knollman and J. J. Hartog, Shear modulus gradients in adhesive interfaces as determined by means of ultrasonic Rayleigh waves, J. Appl. Phys. 53, Part I, 1516 (1982). 

An ultrasonic Rayleigh wave detection system was developed and tested for fast NDE inspection of ceramic bearing balls. The Rayleigh wave system uses a phased-array probe consisting of a single assembly of 32 elements at a frequency of 16.5 MHz. The detection... 

Figure 6.5 Shear modulus, Ga, of an epoxy adhesive, as determined by an ultrasonic Rayleigh wave technique, as a hmction of the thickness of the adhesive layer from the adhesive/aluminium alloy interface [20].

Based upon a piezoelectric 1-3-composite material, air-bome ultrasonic probes for frequencies up to 2 MHz were developped. These probes are characterized by a bandwidth larger than 50 % as well as a signal-to-noise ratio higher than 100 dB. Applications are the thickness measurement of thin powder layers, the inspection of sandwich structures, the detection of surface near cracks in metals or ceramics by generation/reception of Rayleigh waves and the inspection of plates by Lamb waves. 

Chubachi, N. (1985). Ultrasonic microspectroscopy via Rayleigh waves. In Rayleigh-wave theory and applications (ed. E. A. Ash and E. G. S. Paige), pp. 291-7. Springer-Verlag, Berlin. [ 149]... 

Hasegawa K. and Koshiba M., Finite-element solution of Rayleigh-wave scattering from reflective gratings on a piezoelectric substrate, IEEE Trans. Ultrason. Ferroelectrics Freq. Contr., 37, 99-105, 1990. 

Shiokawa S et al (1989) Liquid streaming and droplet formation caused by leaky Rayleigh waves, hi IEEE ultrasonics symposium. IEEE, Montreal... 

There are three ways of measuring ultrasonic birefringence. To measure stress in an entire specimen, one may measure the time of flight of ultrasonic waves as a function of propagation direction. For smaller sections of sample, shear wave velocities are measured as a function of the orientation of the plane of oscillation of the shear wave. Surface stress can be ultrasonically measured using the velocity of Rayleigh waves as a function of direction. Any of these methods will yield the direction of principle stress and relative stress intensities between samples of identical materials. To find actual values of stress, one must know the value of the acoustoelastic coefficient of the material. An experimental setup for measuring bulk acoustoelastic coefficients has been reported by Koshti. ... 

De Billy, M., Casakany, A., Adler, L., and Quentin, G. (1983). Excitation of backward ultrasonic leaky Rayleigh and Leaky Lamb waves. IEEE 1983 Ultrasonics Symposium, pp. 1112-15. IEEE, New York. [116]... 

Laser ultrasonic transducers are truly non-contact devices which effectively avoid acoustic coupling problems (e.g. damping in the transducer and couplant reflection and transmission losses at the interface). Most laser ultrasonic devices have been used for excitation and detection of bulk elastic waves in point source or planar geometry, but also surface acoustic (Rayleigh or Brillouin) waves. Unlike the bulk wave regime, only one sample side is needed for excitation and detection when surface waves are used. This not only renders the measurements easier, but also avoids the need for an accurate knowledge and uniformity of the sample thickness. In addition, the excitation laser can be focused using cylindrical lenses in order to obtain an excitation line. 

A back-scattered Rayleigh surface wave is the leaky ultrasonic energy returning to a transmitting transducer — along the opposite direction to the incident beam — from the... 

Thompson et al. described a series of ultrasonic techniques used for in-.situ measurements of elastic constants on thick-walled submersible vessels [149]. The elastic constants can provide information about fabrication errors such as wavy fibers and fiber disbonds. Elastic constant measurements can be performed using Rayleigh or Lamb wave modes, or by using angle beam techniques, It was shown that the effect of the ani.sotropy increases... 

Weber, A.H., Weiss, C. and Hunklinger, S. (1991) Comparison of Rayleigh and Sezawa wave modes in Zn0-Si02-Si structures. Proceedings of the IEEE Ultrasonic Symposium, 1, 363. 

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