Diffraction effects of planar transducers using a numerical expression for edge waves

Abstract

It is well established that the field from uniformly vibrating piston transducers may be considered as being derived from two components: a plane wave and an edge wave. These have been both predicted and observed in practice, but it would seem that a mathematical expression for the edge-wave component has not yet been developed fully. In this article, expressions are developed for the pressure and particle velocity edge waves that can be used to calculate the field that results when a plane wave is diffracted by an edge. The expressions are used to study a particular example, namely, that of an arbitrarily shaped piston radiator. The results for certain situations are shown to agree with existing solutions for a disk source.

Laser-induced ultrasonic waveform derivation and transition from a point to a homogeneous illumination of a plate

“…The simulations of the epicentral ultrasonic waveforms as induced by the pressure and thermal expansion sources in transition from a point to a quasi-limitless extent from Figs. 2 and 3 show expected characteristics, as inferred from the various sources in the literature [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44]. In fact, they show much more as the surface source enlargement seamlessly connects the two limiting extremes.…”

“…A consistent mathematical description of ultrasound generation mechanisms in laser ultrasonics is achieved by implementation of analogous formulations used for mechanical excitations of matter that are rooted in Green's function formalism as well as known theoretical descriptions of excitations of illuminated matter [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44]. Their additional expansion from a point-to-point approximation to an arbitrary volume-to-point and volume-to-volume formulation is achieved by employing statistically streamlined Huygens' and superposition principles by means of geometric probability theory [51,52,…”

“…While some condensed volumes on the matter in general have been compiled [12,13,14,15,16,17,18], most of the relevant research is mainly scattered in time and throughout literature. One can find, for example, expositions on pressure-induced [19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35] as well as thermal-expansion-induced [26,27,28,29,30,31,32,33,35,36,37,38,39,40,41,42,43,44] ultrasound propagation in a half-space [21,22,23,24,25,26,27,...…”

A model for transient ultrasonic field in solid generated by a transducer in immersion

“…Ultrasonic modelling of transducer radiation and flaw scattering is very helpful for explicit physical interpretations of the results of measurements, optimal transducer design and measurement system arrangement [1][2][3][4][5][6][7][8][9][10][11][12]. In ultrasonic imaging and automatic ultrasonic testing, the immersion mode is widely employed to remove the coupling problem and to enhance the inspection speed [13][14][15][16][17][18].…”

Deformation of sound pressure pulse and that of particle velocity pulse with diffraction.

“…In the history of analysis of ultrasonic propagation, nearfield has been extensively investigated theoretically1-10) and experimentally.2,5,6) And, waveform of ultrasonic pulse has also been analyzed by many authors. [11][12][13][14][15][16][17] But they investigated only the sound pressure11-13) or the waveform where a point receiver was set in the field. [14][15][16][17] In this article are reported results of precise computation by Fourier's analysis for deformation of axial component of particle velocity pulse with diffraction, together with sound pressure pulse, including the case where a circular flat receiver is set against the circular flat transmitter.…”