ANSYS周期性压电结构对机械波滤波特性的研究
时间:2018-08-27 14:32 来源:毕业论文 作者:毕业论文 点击:次
| 摘要：1880年，法国物理学家P.Curie和P.Curie兄弟发现，在某些晶体特定方向上施加一定压力或拉力，晶体的某些对应表面上分别出现正负束缚电荷，其电荷密度与施加的压力大小成比例，这种效应被称为“压电效应”。次年，Lippmann跟据热力学方法，应用能量守恒定律、电量守恒定律，推知逆压电效应的存在。后来，Curie兄弟通过实验证实了逆压电效应，并给出数值相等的石英晶体的正、逆压电效应的压电常数。27506 某些电介质在沿一定方向上受到外力作用而变形时，其内部会产生计划现象，同时在它的两个相对表明产生正负电荷。去掉外力后，它又会恢复到不带电状态，这种现象称为正压电效应。当作用力的方向改变时，电荷的极性也随之改变。相反，当在电介质的极化方向上施加电场时，这些电介质也会发生变形，电场去掉后，电介质的变形随之消失，这种现象称为逆压电效应，或称为电致伸缩效应。 压电晶体具有介电性质与弹性性质，介电性质与弹性性质之间的耦合效应，称为机电耦合效应。机电耦合效应的线性部分即为压电效应，晶体的介电性质需要用介电常数来描写，晶体的弹性性质需要用弹性常数来描写；同样，压电晶体所特有的压电性质需要用压电常数来描写。晶体的介电常数、弹性常数、压电常数都与晶体的对称性密切相关。 本文主要研究内容：本文主要研究一文周期性压电结构的机械波滤波特性，重点研究主动式周期性压电结构的滤波特性与被动式周期性压电结构的滤波特性之间的区别。具体操作是：以被动周期弹簧-质量模型为例，通过改变被动周期弹簧-质量系统中的弹簧刚度等参数，研究其滤波特性，进而推导出一文周期性压电结构的机械波滤波特性。 毕业论文关键词 压电体 压电效应 信号转换 介电性质 弹性质 机电耦合 Title The action of periodic piezoelectric structure to zhe filter Characteristic of mechanical wave. Abstract 1880, P.Curie and P.Curie brothers discovered that applying pressure or tension in a particular direction some crystals are bound by the emergence of positive and negative charge on the number of the corresponding surface of the crystal, the pressure is proportional to the size of the charge density and applied, this effect is called "piezoelectric effect." The following year, Lippmann based on thermodynamics, energy conservation and the use of two power conservation law to infer the existence of a pre-reverse piezoelectric effect. After, Curie brothers experimentally confirmed that the inverse piezoelectric effect, and gives a value of piezoelectric constant equal to n, the inverse piezoelectric effect of quartz. Some dielectrics by external force in a certain direction and the deformation, the internal program will produce the phenomenon, while its opposite shown to produce positive and negative charges. After the removal of the external force, it will be restored to the uncharged state, a phenomenon known piezoelectric effect. When the forces of change in direction also changes the polarity of the charge. On the contrary, when the electric field is applied in the direction of polarization of the dielectric, which dielectric will be deformed, after the electric field is removed, the deformable medium power disappear, a phenomenon known as the inverse piezoelectric effect, or electrostrictive effect. The piezoelectric crystal has dielectric properties and elastic properties, dielectric properties and the coupling effect between the elastic properties, called electromechanical coupling effects. Electromechanical coupling effect of the linear part is the piezoelectric effect, the dielectric properties of the dielectric constant of the crystal needed to describe the elastic properties of the crystal elastic constants needed to describe; similarly, the piezoelectric properties of piezoelectric crystals-specific needs with the pressure dielectric constant to describe. Permittivity crystal elastic constants, piezoelectricconstants are closely related to the crystal symmetry. (责任编辑：qin) |