Case study of guided wave propagation in a one-side water-immersed steel plate

This paper presents a case study of guided waves in a steel plate with one side immersed in water. A hybrid sensing system that uses PZT as the guided wave actuator and a scanning laser vibrometer as the guided wave receiver is employed to acquire the time–space wavefield data. By using the two dimensional Fourier transform, the time–space wavefield is transformed into the frequency–wavenumber domain where the wave modes and the guided wave dispersion can be determined. The study confirms the existence of quasi-Scholte wave in the one-sidedly water-immersed plate in addition to fundamental guided waves. The results also show the quasi-Scholte wave can be directly generated and measured in the immersed plate at low frequencies using the present sensing system. Through pitch–catch sensing tests, the influence of water on guided wave propagation in the one-side water-immersed plate is investigated. It is seen that the water level affects the wave propagation time linearly and can be potentially used for estimation of water level in a container.