Improvement of broadband low-frequency sound insulation of sandwich plates with negative Poisson's ratio butterfly-shaped auxetic cellular

Abstract

The novel cellular cores auxetic metamaterials with negative Poisson's ratio (NPR) exhibit unique mechanical deformation characteristics compared to conventional cellular cores, which can be further exploited in modeling lightweight sandwich structures. The butterfly-shaped auxetic cellular is not only an improvement upon the traditional re-entrant auxetic cellular with NPR, but also a kind of bionic design, which possesses higher stiffness and thus offers greater potential for sound insulation. Based on this, the present article explores a study of the sound transmission characteristics exhibited by sandwich plates with butterfly-shaped auxetic cellular core layers. Firstly, the motion equation is derived based on the first-order shear deformation theory and Hamilton's principle, which is further solved analytically based on fluid-structure coupling conditions and combined with Navier method. Then, the sound transmission loss (STL) is analytically described. The correctness of the theoretical model is verified by comparing the theoretical solution with the calculation results of the commercial software COMSOL and the experimental results of impedance tube sound insulation tests. Based on the theoretical model, it is calculated that the sound insulation effect of butterfly-shaped auxetic cellular core is better than that of traditional re-entrant cellular with NPR. An analysis is subsequently conducted to explore the impact of key parameters on the STL of the butterfly-shaped cellular sandwich plates.