The Research Of Vibration Band Gap Properties In Ternary Periodic Composite Structure

As a new functional structure, periodic composite structure is a combination of two or more elastic materials in accordance with a certain periodicity. Periodic composite structure has a band gap characteristics of vibration in specific frequency range, making vibration cannot propagate in the structure. Thus there is a new way of thinking to isolate, damp and control vibrations in engineering structures. Periodic composite structure can be placed in the propagation path of vibration. People could also use the idea of periodic composite structure to design structures which would block specific band of vibration propagation in the structures by themselves without any other facilities. Consequently, the study of vibration propagation characteristics of the composite structure has important theoretical and practical significance in isolating, damping and controlling vibrations.Nowadays, we have lots of mature methods to calculate the band gap of the periodic structure. However, for practical engineering applications, they are not convenient and intuitive enough. To solve this problem, based on the mechanism of the locally resonant periodic composite structure, we designed locally resonant periodic composite structural plates, and column structures, which could be used in engineering structures widely. We analyzed geometric parameters, material parameters of transverse vibration band gaps of two-dimensional locally resonant thick plates, as well as horizontal and vertical vibration of the one-dimensional locally resonant columns. According to these factors, as well as lots of calculations and fitting, we gave the prediction formulas of the upper and lower bounds which describe the first transverse band gap of two-dimensional locally resonant thick plates, the prediction formulas of the upper and lower bounds which describe the first vertical vibration band gap of the one-dimensional locally resonant columns and the prediction formulas of the upper and lower bounds which describe the first horizontal vibration band gap of the one-dimensional locally resonant columns.We also compared prediction formula calculations with numerical simulation results derived from finite element software Comsol Multiphysics. Comparison results indicate that the difference between the two is small, and we could apply the prediction formula in real projects.