Ultrasonic Waves In Solids Research Articles

Strain Amplitude of Mc/sec Ultrasonic Waves in Solids

The strain amplitudes of 10 Mc/sec sound waves in solids were measured under conditions in which standing waves were set up, as well as under pulsed conditions. The methods used were (1) measuring the equivalent electrical resistance of the transducer, (2) measuring the heating produced by absorbing the sound waves, (3) diffraction of light from standing acoustic waves, and (4) the changes in a nuclear magnetic-resonance-absorption signal produced by the sound waves. All these methods were in substantial (±20%) agreement with one another. Measurements with different characteristics for the coupling between the transducer and sample showed the importance of this thin film. The highest strain amplitudes were obtained at frequencies slightly higher than the quartz-transducer resonant frequency. Even higher strains could be obtained with coupling films approximately 14-wavelength thick.

Ultrasonic Waves of Finite Amplitude in Solids

The distortion of an initially sinusoidal ultrasonic wave in solids has been experimentally observed. The dependence on pressure amplitude of the propagation characteristics of such waves is discussed, and the relationship between this phenomenon and third-order elastic constants used to describe anharmonicity of solids is pointed out.

Resonant Interaction of Two Ultrasonic Waves in Solids

In a recent theoretical paper, Jones and Kobett [J. Acoust. Soc. Am. 35, 5 (1963)] have shown that two monochromatic elastic waves in a nonlinear solid interact rather strongly if they intersect at a certain angle. When this condition of resonance is satisfied, the theory further predicts that a 3rd wave may be generated at the “point” of intersection. The generated wave will have a frequency (ω1±ω2) and wavevector (k̄1±k̄2), where the subscripts refer to properties of the two primary waves. An experimental study of interaction between pulsed ultrasonic beams has shown that the theoretically predicted 3rd wave can be detected with easily attainable primary wave intensities and frequencies in the 1- to 15-Mc/sec range. Both sum and difference frequencies have been generated in specimens of fused silica, polycrystalline aluminum, and polycrystalline magnesium. Experimental details are given and possible methods of measuring third-order elastic constants are discussed. [Work supported by the Aeronautical Systems Division, Wright-Patterson Air Force Base.]

Generation and Detection of Ultrasonic Waves in Solids by Small Barium Titanate Transducers

Generation and Detection of Ultrasonic Waves in Solids by Small Barium Titanate Transducers

固体中の超音波(II) : 超音波の振動数における固体の弾性と内部摩擦

固体中の超音波(II) : 超音波の振動数における固体の弾性と内部摩擦

Ultrasonic Waves in Solids(I) : Proper Vibrations of Solids at Ultrasonic Frequency

Ultrasonic Waves in Solids(I) : Proper Vibrations of Solids at Ultrasonic Frequency