A nonlinear diatomic acoustic metamaterial (NDAM) was proposed,and a wave dynamics model was con-structed by using the multi-scale method.Firstly,the elastic wave propagation mechanism in frequency domain was studied.The results show that the band-gap width can be adjusted by changing intensity of non-linearity and the diatomic mass ratio,and different spring type can influence the elastic wave propagation in the structure.Furthermore,the wave spatial-spectral properties of elastic waves in a one-dimensional chain were studied.It is shown that the interaction of nonlinearity and dis-persion relation will produce acoustic-mode localization waves in both nonlinear monatomic and diatomic systems.Howev-er,optical-mode localization wave is not obvious in NDAM.This study provides a theoretical guidance for the design of new acoustic switches,acoustic lens,isolators etc.in the fields of vibration and elastic wave control.
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