Interaction of a screw dislocation with an interfacial edge crack in a two-phase piezoelectric material

The interaction of a screw dislocation with an interfacial edge crack in a two-phase piezoelectric medium is investigated. Closed-form solutions of the elastic and electrical fields induced by the screw dislocation are derived using the conformal mapping method in conjunction with the image principle. Based on the electroelastic fields derived, the stress and electric displacement intensity factors, the image force acting on the dislocation are given explicitly. We find that the stress and electric displacement intensity factors depend on the effective electroelastic material constants. In the case where one of two phases is purely elastic, the stress intensity factor and image force are plotted to illustrate the influences of electromechanical coupling effect, the position of the dislocation and the material properties on the interaction mechanism. The project supported by the Doctoral Foundation of Hebei Province (B2003113)     

TWO-DIMENSIONAL ELECTROELASTIC FUNDAMENTAL SOLUTIONS FOR GENERAL ANISOTROPIC PIEZOELECTRIC MEDIA

I.IntroductionDuetotheirintrinsiccouplingeffectbetweenmechanicalandelectricalfields,piezoelectricmaterialshavebeenwidelyusedintechnologyastransducersandsensorsand,morerecently,asactuatorsinsmartstructures.lnordertooptimizetheirmicrostructuresandunderstand…     

ELECTRO-ELASTIC GREEN'S FUNCTIONS FOR APIEZOELECTRIC HALF-SPACE ANDTHEIR APPLICATION

I.IntroductionItiswell'knownthatoneofthemostpowerfultoolsinlinearfieldtheoriesistheGreen'sfunction.Fore1asticity,considerableresearchcanbefoundintheliterature.However,theGreen'sfunctionforpiezoe1ectricityisratherlimitedduetotheanisotropyandelectromechanic…     

磁电弹板双材料板中厚度-扭曲波的传播

研究了磁电弹双材料板(板的上下表面是机械自由、电学开路和磁学短路的) 中厚度-扭曲波的传播. 基于磁电弹全耦合的本构方程, 首先推导了厚度扭曲波传播的一般解, 然后利用 边界条件和界面条件得到了频率方程. 数值算例分析了压电(BaTiO_{3})-压磁 (CoFe_{2}O_{4})双材料板中厚度扭曲波传播时, 位移、电势和磁势的变化特征以 及模态数与几何尺寸的关系.     

层状压电半空间中的螺位错

研究了层状压电半空间中的螺位错与界面的相互作用,应用傅立叶变换的方法,推导了压电层和基体的弹性场和电场,并在此基础上给出了像力的表达式,分析了几何尺寸和材料的相对刚度对像力和界面应力的影响.结果表明:压电效应的存在可以改变位错与界面的相互作用机理;弹性常数的差异对界面应力有较大的影响.     

点简支正交各向异性矩形薄板弯曲的精确解

本文利用迭加原理,给出了点简支正交各向异性短形薄板弯曲问题的封闭的级数式解答.简支点的位置和横向载荷的分布均可任意.用本文的级数解给出的算例与以往的数值解是十分一致的.     

压电螺位错与椭圆夹杂的电弹相互作用

研究了压电材料中压电螺位错与椭圆夹杂的电弹相互作用·　基于扰动概念和级数展开方法 ,推导了基体和夹杂的弹性场和电场 ,在此基础上给出了作用于位错上像力的表达式·　通过分析基体与夹杂的相对刚度和机电耦合强弱对像力的影响 ,得到了新的相互作用机理·     

Analysis of the electrically forced vibrations of piezoelectric mesa resonators

We study the electrically forced thickness-shear and thickness-twist vibrations of stepped thickness piezoelectric plate mesa resonators made of polarized ceramics or 6-ram class crystals. A theoretical analysis based on the theory of piezoelectricity is performed, and an analytical solution is obtained using the trigonometric series. The electrical admittance, resonant frequencies, and mode shapes are calculated, and strong energy trapping of the modes is observed. Their dependence on the geometric parameters of the resonator is also examined.     

偏压电场作用下磁电弹板中Lamb波传播研究

基于磁电弹性材料的本构关系和运动微分方程,研究了磁电弹板中Lamb波的传播特性.在电磁开路和短路两种边界条件下,导出了偏压电场作用下磁电弹板中Lamb波的对称模态和反对称模态的相速度方程,求解了相应的应力场.通过数值算例分析了偏压电场对相速度和应力场的影响.结果表明,偏压电场对相速度有较大影响,对应力场几乎没有影响.研究成果可为设计磁电换能器提供一定的理论参考.     

Existence of Shear Horizontal Surface Waves in a Magneto-Electro-Elastic Material

The existence of shear horizontal surface waves in a magneto-electro-elastic （MEE） half-space with hexagonal （6mm） symmetry is investigated. The surface of the MEE half-space is mechanically free, but subjected to four types of electromagnetic boundary conditions. These boundary conditions are electrically open/magnetically closed, electrically open/magnetically open, electrically closed/magnetically open and electrically closed/magnetically dosed. It is shown that except for the electrically open/magnetically closed condition, the three other sets of electromagnetic boundary conditions allow the propagation of shear horizontal surface waves.