Acoustic microscopy investigations of nonplanar surfaces

Spherical inclusion characterization by the acoustical microscope: Axisymmetric case

“…His experimental results clearly show the need of carrying out proper theoretical analysis for nonplanar specimens as well. The simple ray optical theory of the V(z) curve synthesis near the top of a sphere was given by Hadjoub et al 16 Theoretical analysis of the interaction of converging acoustic beams and spherical balls in a coupling liquid show that one can accurately determine the diameter of a spherical particle from its V(z) curve. [17][18][19][20] In a recent paper Lobkis et al 21 extended this analysis to spherical cavities in a solid located below the solid-liquid interface.…”

V(Z) curve formation of solid spherical microparticles in scanning acoustic microscopy

“…The distance between these two maxima is equal to the radius of the sphere (see Table 1). Some smaller peaks arising near the TM can be attributed to the interference between the Rayleigh and specula waves and are discussed elsewhere (Weglein, 1981;Hadjoub et al, 1991). In the region Z > 0 (the focal point is located below the sphere's centre or CM) two other maxima can be easily distinguished.…”

“…Those papers have demonstrated the possibility of determining the Rayleigh wave velocity for spherical objects using V(Z) curve techniques (Weglein, 198 1;Porier & Cheeke, 1982;Porier et al, 1984). In a recent paper (Hadjoub et al, 1991) the V(Z) curves of spherical particles were investigated and the contribution of Rayleigh waves to the V(Z) curve was considered experimentally and theoretically following the same principles used for planar surfaces (Parmon & Bertoni, 1979). However, in order to characterize spherical particles or to obtain information about the particle's size and its elastic properties it is necessary to consider the V(Z) curve formation when the focal point is moved along the diameter of the particle.…”

Mechanical characterization of thin layer of chromium on steel substrate by acoustic methods

“…Aperture angles of acoustic transducers strongly influence the acoustic signature of the examined material [20,21]. For different apertures, one can observe either the longitudinal mode alone or the longitudinal and Rayleigh modes simultaneously.…”