Propagation behavior and low frequency band gap of transverse shear-horizontal interface waves in two perfectly-bonded functionally-graded half-spaces

An analytical solution is carried out on the propagation of the transverse shear-horizontal interface waves in the perfect interface of two functionally graded half-spaces in which the bulk shear wave velocities at the positive and the negative infinite point are different. The dispersion curves results reveal a special phenomenon that the low frequency shear-horizontal waves cannot propagate in the structure but the high frequency shear-horizontal waves can. By analyzing the amplitude of the displacement, it is found that the energy hardly concentrate on the interface in this structure. The theoretical foundation of the transverse shear interface waves and their low frequency band gaps can serve as a basis for graded material characterization and for designing novel acoustic devices.