【作者】 王晓；

【导师】 王晓明；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2012， 硕士

【摘要】 周期结构是按照一定的规则和周期设计并制造的,由若干相同的子结构通过一定的方式连接形成。通过调整子结构的形状、各组成成分的排布和体积分数,可以改变周期结构的宏观性能。周期结构具有“禁频”特性,对频率处于“禁频”范围内的弹性波或振动,在周期结构中传播时,能量和幅值会产生衰减。本文基于压电被动阻尼技术,提出了一种新型的周期结构单胞,即子结构。以压电杆的形式,将包含外部电路的压电单元加入到单胞中,从而将压电材料用于提高周期结构的阻尼。对于无限周期结构,根据Bloch定理,将问题转换为对单胞的求解。采用有限元法建立压电周期结构的单胞模型,通过施加周期边界条件,将独立单胞转换为无限周期结构中的任意单胞。根据损耗因子与材料阻尼系数之间的等效关系,将单胞的动力平衡方程转化为包含阻尼项的复系数特征值方程,实现对压电周期结构阻尼特性的分析。根据上述理论,编写了分析压电周期结构阻尼特性的算法程序,通过对具体算例进行迭代求解,得到了压电周期结构的频散关系和阻尼特性,对于周期结构减振的研究和应用,有一定理论指导意义。更多还原

【Abstract】 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.更多还原