Propagation of Ultrasonic Shear Horizontal Waves in Rectangular Waveguides

The aim of this paper is to investigate the propagation of ultrasonic shear horizontal guided waves along waveguides with a rectangular cross-section and with a finite constant and variable width and to determine the peculiarities of propagation of those waves. The dispersion curves of guided waves in finite-width waveguides were modeled by using a semi-analytical finite element (SAFE) technique. The propagation of pulsed shear horizontal ultrasonic guided waves was investigated numerically by using 3D finite element modeling. It was found that in the case of finite-width waveguides, the SH0 shear horizontal wave splits into a family of SH-type dispersive modes propagating with different phase velocities. It was also found that the number of propagating modes depends on the width-to-thickness ratio. The first time spatial distributions of pulsed displacements across the waveguide were determined for waveguides of different widths. Investigation of the waveguides with a rectangular cross-section and varying lateral dimensions was performed. It was found that by properly selecting the geometry of the transient zone of waveguides with a rectangular cross-section, it is possible to improve the performance of such waveguides, e.g. to increase the amplitude of the transmitted pulse type signal without significant distortions of the waveforms.