Research On Damping Characteristics Of Piezoelectric Periodic Structures

Periodic structures, which consist of several identical substructures arranged in a definite way, are designed and manufactured in accordance with certain principles. The macroscopic properties of periodic structures could be changed by adjusting the shape, distribution and volume fraction of the composition of the substructure. Meanwhile, periodic structures have a band-gap. The energy and amplitude of the elastic wave or vibration with the frequency in the band-gap will reduce while propagating in periodic structures.In this thesis, a new type of unit cell of periodic structures is proposed, i.e., the substructure. In order to improve the damping of periodic structures using the piezoelectric material, piezoelectric elements shunted with electric circuits are added to the cell. For infinite periodic structures, the problem is reduced to one cell by Bloch’s theorem. An independent unit cell is converted to anyone of periodic structures by applying the periodic boundary conditions to the model established by the finite element method. Based on the equivalent relation between the loss factor and the structural damping, the dynamic equilibrium equations of the unit cell are reduced to complex coefficient eigenvalue equations.In view of the above observations, the program for analyzing the damping property of piezoelectric periodic structures is written, and a specific example is given. The dispersion relation and damping property of piezoelectric periodic structures are obtained by iteration computation. Our research will provide a theoretical basis for further study.