Focusing and Self-Bending of Flexural Waves by Meta-Slabs with Subunits of Varying Thicknesses

In this paper, we numerically investigate the meta-slabs with subunits of varying thicknesses for focusing and self-bending of incident flexural waves. Finite element (FE) simulations for wave propagations in the submit are conducted to obtain the subunit thickness variation range that assures high transmission and phase coverage of 2π needed tbr the design of the meta-slabs. Based on the generalized Snell's Iaw (GSI), we derive the phase profiles along the meta-slabs and design them for focusing and self-bending of incident flexural waves. FE simulations are conducted to demonstrate focusing with the energy efficiently concentrated near the focal position, which can be used in energy harvesting. Self-bending with the parabolic and circular trajectories for the designed meta-slabs with two corresponding configurations are also demonstrated. The areas surrounded by the trajectories have very low energy, which can be used in vibration isolation.