Acoustic Fano-like resonance phenomenon based local resonance generated by soft material cylinder

Herein, we developed acoustic Fano-like resonance phenomenon based local resonance. Unlike the previous mentioned coupled pillar design, asymmetrical space distributions can be designed by mode-selective feature of a cylinder with fixed top and bottom surface. For verifying the proposed phenomenon, two topologies are designed which are hybrid hard and soft cylinders topology and double soft cylinders topology. The proposed topologies are composed of three-unit cells, each employing two geometry identical ring-shaped pillars clamped on top and bottom surface of the square wave cavity. The lattice in the middle is consisted of two kinds of cylinders made by soft TPU material and hard resin material in the hybrid topology, while the middle lattice of the double soft topology is consisted of two soft cylinders. The corresponding Fano resonance are confirmed through both simulation and experiments. Both designs can generate Fano-like resonance phenomenon due to the different deformation under the same frequency leading to the local space asymmetric. The asymmetrical space has the capability of triggering standing pressure wave, which couples with the propagating traveling wave for constructive and destructive sound transmission.