Manipulation of shear horizontal guided wave with arbitrary wave fronts by using metasurfaces

Abstract

In this work, we proposed a general method to manipulate the fundamental shear horizontal wave (SH0) in plates with arbitrary wave fronts by using metasurfaces consisting of multiple parallel strips. Firstly, the guided waves in infinitely long rectangular strips with different widths were analyzed. The transmission characteristic of the fundamental shear horizontal wave in infinitely long rectangular strips (quasi-SH0) was calculated and the relationship between the phase shift and the frequency-width product is obtained. Secondly, the mode conversion was analyzed for the oblique incidence of SH0 wave from a large plate to a strip, and it was found that the Lamb wave S0 also appeared. Then, the design method for metasurfaces under the incidence of SH0 wave with arbitrary wave fronts was proposed. Two types of metasurfaces, i.e. the flat lenses and the ring-type source illusion devices, were designed to validate the proposed design method. Both simulations and experiments were conducted in which the thickness-shear d15 piezoelectric rings and strips were used as the SH0 wave exciters and the d24 face-shear wafers were used as the wave receiver. Results showed that using the proposed method, different functional metasurfaces can be designed and work well under arbitrary wave fronts incidence. The proposed metasurface design method is potentially useful for practical applications such as nondestructive testing, advanced signal modulation and seismic wave controlling.