Abstract: A novel low frequency vibration isolator is established. The isolator is called periodic arch structure, which is composed of a number of identical reordered arch structures connected together along the vertical direction. The propagation characteristics of flexural waves in periodic arch structure are investigated by combining Bloch theorem with the finite element method, and the effect of dimension and material to band gaps are discussed. The discussions find that the height of the arch structure has no influence to the band gap, and the short height insulated low frequency vibration can be realized, which can solve the problem of dimension limit in practical application. The discussions also find that the range of band gap can be reduced by increasing the length of the structure, decreasing the thickness, modulus and density of the material. The predictions are validated by computation and experimental analysis of the harmonic responses of a finite structure with five unit cells. These studies provide guidelines to designing periodic structures for low frequency vibration attenuation.

Key words: Arch structure, Elastic band gap, Finite element method, Low frequency vibration isolation