are designed to achieve abnormal acoustic characteristics
and the formation mechanisms for anisotropic reflection characteristics and equivalent parameters are systematically studied. Acoustic properties of the three types of asymmetric acoustic metamaterials are studied by simulation and experiment
and The experimental results show that anisotropic reflection phase can be realized when material asymmetry and geometrical asymmetry form asymmetric resonance characteristics
and anisotropic reflection amplitude can be further realized by considering material loss. Asymmetric resonance characteristics also produce anisotropic equivalent parameters
and a modified direct method is proposed to obtain unified equivalent parameters for asymmetric acoustic metamaterials. The calculated unified equivalent parameters have a corresponding relationship with amplitude of transmission and meet the requirements of passive materials
which validates the correctness of the method. The present work can provide some references for the realization of acoustic devices with zero reflection.
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