粘结层对悬臂压电俘能器力电性能影响的研究

发布时间：2019-06-22 07:35

【摘要】：压电俘能器是一种利用压电材料的机电耦合效应,将环境中的机械能转化为电能的智能结构。基于共振俘能方式的俘能器通常采用悬臂梁式结构,由粘结剂将压电层与弹性层粘结在一起,悬臂梁端部将产生的较大应变,且在高阶振动的情况,悬臂梁将出现变形拐点,有的部分出现拉伸变形,而有的部分出现压缩变形,若将压电片满布悬臂梁上,则两部分产生的电荷互相抵消,俘能效率反而降低,所以一般只将压电片铺设在变形较大的根部,而非布满形式。此外,由于压电层材料与弹性层材料的几何参数与材料参数的不一致,当俘能器受环境激励时,粘结剂在传递弹性层变形的过程中易出现应力的不均匀分布,且在压电层自由端处易出现较大的应力集中,从而影响压电俘能器的俘能输出。因此有必要探明粘结层对俘能输出的影响规律。本文以上述非满布压电层的悬臂梁俘能器为研究对象,采用双参数模型模拟粘结层,并基于分布参数模型建立悬臂梁式压电俘能器的控制方程,当激励频率给定后,控制方程转化为以波数为特征值的特征方程,求解该方程得到12个特征模态,将这些模态线性叠加即可给出该问题的解,其组合系数由边界和连接条件确定。此外,通过三维有限元分析,并结合前人实验结果,互相对比验证,在理论正确性得到验证后,本文还研究了俘能器弹性层、粘结层和压电层的材料参数和几何参数对符能输出的影响。具体讲,本文共分为五章:第一章给出本文的研究背景和意义;第二章对文献中粘结层简化的理论模型和俘能器分析模型进行了回顾和讨论;第三章基于双参数模型理论,考虑粘结层的影响建立压电俘能器的控制方程,给出俘能输出解析解,并用理论分析所得的俘能输出与ANSYS有限元模拟进行对比验证,以及与传统分析结果进行比较;第四章针对俘能器中粘结层的厚度、弹性模量,压电层的铺设长度、厚度及弹性模量,弹性层的厚度及弹性模量等参数对俘能输出的影响进行详细分析讨论,观察不同参数情况下的粘结层界面应力状态和电压输出,总结出其变化规律。第五章针对前文进行回顾与总结,并对未来可行的研究进行了展望。通过本文的理论探讨,为压电俘能器的设计与分析提供了更精确的理论支持。
[Abstract]:Piezoelectric catcher is an intelligent structure which converts the mechanical energy in the environment into electric energy by using the electromechanical coupling effect of piezoelectric materials. The energy capture device based on resonance energy capture mode usually adopts cantilever structure. If the piezoelectric layer is bonded with the elastic layer by the binder, the large strain will be produced at the end of the cantilever beam, and in the case of high-order vibration, the cantilever beam will appear deformation inflection point, some parts will appear tensile deformation, and some parts will appear compression deformation. If the piezoelectric film is fully covered on the cantilever beam, the charges generated by the two parts will cancel out each other. On the contrary, the energy capture efficiency is reduced, so the piezoelectric film is usually laid at the root of large deformation, rather than full of form. In addition, due to the inconsistency between the geometric parameters and the material parameters of the piezoelectric layer material and the elastic layer material, when the catcher is excited by the environment, the adhesive is prone to the uneven distribution of stress in the process of transferring the deformation of the elastic layer, and a large stress concentration is easy to appear at the free end of the piezoelectric layer, thus affecting the capture energy output of the piezoelectric catcher. Therefore, it is necessary to find out the influence of bonding layer on the output of capture energy. In this paper, the cantilever beam catcher with non-fully distributed piezoelectric layer is taken as the research object, and the two-parameter model is used to simulate the bonding layer, and the governing equation of the cantilever piezoelectric catcher is established based on the distributed parameter model. When the excitation frequency is given, the governing equation is transformed into the characteristic equation with wavenumber as the characteristic value, and 12 characteristic modes are obtained by solving the equation. The solution of the problem can be given by linear superposition of these modes. The combination coefficient is determined by the boundary and connection conditions. In addition, through three-dimensional finite element analysis and previous experimental results, the theoretical correctness is verified, and the effects of material parameters and geometric parameters of the elastic layer, bonding layer and piezoelectric layer on the output of energy are also studied in this paper. Specifically, this paper is divided into five chapters: the first chapter gives the research background and significance of this paper, the second chapter reviews and discusses the theoretical model of bond layer simplification and the analysis model of catcher in the literature. In the third chapter, based on the two-parameter model theory, the governing equation of the piezoelectric catcher is established considering the influence of the bonding layer, and the analytical solution of the capture energy output is given. The capture energy output obtained by the theoretical analysis is compared with the ANSYS finite element simulation, and the results are compared with the traditional analysis results. In chapter 4, the effects of the thickness of bond layer, elastic modulus, laying length of piezoelectric layer, thickness and elastic modulus, thickness of elastic layer and elastic modulus on energy capture output are analyzed and discussed in detail, the interfacial stress state and voltage output of bond layer under different parameters are observed, and the variation law is summarized. The fifth chapter reviews and summarizes the above, and looks forward to the feasible research in the future. Through the theoretical discussion in this paper, it provides more accurate theoretical support for the design and analysis of piezoelectric catcher.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM619

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