A real-time 32-element synthetic aperture acoustic imaging system has been developed. We can test new ideas for the system by using an acoustic array and carrying out image reconstruction on a computer. Contour plots of simple images are shown to illustrate the resolution (0.4 0.5 mm in range and transverse resolution) and sidelobe levels obtained with this synthetic-aperture technique. Rayleig...

The characteristics of two types of surface acoustic waves SAWs (Rayleigh waves and Love waves) propagating in bilayered structures of ( 11 2 ¯ 0 ) ZnO/R-sapphire are simulated by a finite element method (FEM) model, in which both SAWs have crossed propagation directions. Furthermore, based on the bilayered structures, the frequency responses of Rayleigh wave and Love wave humidity sensors are ...

This paper illustrates the phenomenon of the critical speed in the range 100300 km/h. A real explanation and a precise calculation of the critical speed seems to rest an unresolved problem in many cases. Some authors, analogous to “Mach effect”, have attributed this phenomenon to the reaching the Rayleigh wave speed of substructure by trains. But this explanation can’t be thorough in many cases...

This article aims to study the interaction of Rayleigh or surface wave with a varying angled wedge using numerical simulations. work uses tools understand this complex problem and fills some existing gaps such as influence frequency geometry (curved vs. sharp transition). Quantitative analysis was carried out by calculating transmission reflection coefficients, qualitative used displacement vec...

A set of time-synchronized strong-motion accelerograms, obtained on the San Juan Bautista 156/101 Separation Bridge in California during the 6 August 1979 Coyote Lake earthquake (ML = 5.9), are used to study the spatial variation of ground motion at the bridge site, including traveling wave effects and the influence of multiple-support excitation. Analysis of the ground motion recorded at the b...