Experimental Demonstration of an Ultrabroadband Nonlinear Cloak for Flexural Waves

Broadband cloaking of flexural waves is a major challenge since the governing equation is not form invariant under coordinate transformations. We fabricate a flexural cloaking structure using only a single material composed of homogeneous and isotropic layers, and then present experimental evidence of the first near-ideal broadband cloak in thin plates. The 3D-printed structure is shown to effectively disguise an object over a broad frequency range (2 kHz-11 kHz). The proposed cloak has potential applications in shielding sensors and sensitive components from vibrations in bridges, automobiles, and aircraft.