The propagation of Lamb waves in a one-dimensional phononic crystal plates bordered with symmetric uniform layers

We investigated theoretically the band structures of Lamb waves in a one-dimensional (1D) phononic crystal (PC) plates coated symmetrically or asymmetrically with finite Tungsten or Silicon loading layers on both sides. Numerical results show that when a thin PC plates is bordered with Silicon loading layers, the midgap frequency of the first band gap of the S₀ mode increases approximately linearly with the increase of the thickness of solid loading layers; this is contrary to the trend of a thin plates bordered with Tungsten loading layers. These properties can be applied to design acoustic sensors for multilayer materials detection and aircraft icing forecast.