Analysis Of The Dynamic Characteristic Of Periodic Structure With Microperforated Damping

Along with the improvement of science and technology, people have put forward higher requirements on the structure vibration and noise. The band gap characteristic of periodic structure providing a new and reliable approach for structure’s vibration and noise reduction has become the focus of research. This thesis studies the dynamic characteristics of periodic structures with negative Poisson’s ratio cell by combination of damping mechanism and theory of periodic structure.Based on the hydraulic fluid mechanics knowledge, this thesis gets a new type of vibration reduction structure, which can be used as the cell of the periodic structure, by combining theoretical study microperforated structure with damping theory. The modal analysis and harmonic response analysis is carried out by using the ANSYS software, and the dynamic characteristic of structure with and without damping is got. The transfer function of the periodic structure cell is obtained by fitting the amplitude-frequency curve with MATLAB software. Through modifying the parameters of the model, the relationship between the coefficients of the transfer functions and the major dimension parameters of the model is established, and its correctness is also verified in this thesis. The dispersion equation of the periodic structures is gained by us ing the transfer function of the periodic structure cell, through which can get dispersion curve.By analysis, a new vibration reduction structure by using the proposed structure cell obtains the satisfactory result of vibration reduction, and has linear viscosity resistance with flexible adjustable range. The transfer function coefficients and the actual structure size have good corresponding relationship and provide reference for improving the quality of the design and shortening design period. One of the coefficients of transfer functions is proportional to the structure’s natural frequencies. The function relation between structure size and transfer function coefficients is obtained which can provide guidance for reducing the natural frequencies of structures. The negative poisson’s ratio change curve of the cell structure and the dispersion curve of the periodic structure are obtained which can provide basis for bandgap design of the periodic structure.