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THE INTERACTION BETWEEN CRACK AND ELECTRIC DIPOLE OF PIEZOELECTRICITY

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Acta Mechanica Solida Sinica 2000年第4期13卷 283-289页

作者： Wang Jiwei kuang zhenbang Shanghai Jiao Tong Univ Dept Engn Mech Shanghai 200240 Peoples R China

Discrete dipoles located near the crack tip play an important rolein nonlinear electric field induced fracture of piezoelectricceramics. A physico-mathematical model of dipole is constructed oftwo gen- eralized concentrated piezoelectric forces with equaldensity and opposite sign. The interaction between crack and electricdipole in piezoelectricity is analyzed. The closed form solutions,including those for stress and electric displacement, crack openingdisplacement and electric potential, are obtained. The function ofpi- ezoelectric anisotropic direction, p_α(θ)=cosθ+p_αsinθ, canbe used to express the influence of a dipole's direction. In the casethat a dipole locates near crack tip, the piezoelectric stressintensity factor is a power function with -3/2 index of the distancebetween dipole and crack tip.

关键词： piezoelectricity dipole stress intensity factor

HIGHER ORDER ASYMPTOTIC FIELDS AT THE TIP OF A SHARP V-NOTCH IN A POWER-HARDENING MATERIAL

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Acta Mechanica Solida Sinica 2002年第2期15卷 102-110页

作者： Wang Weiwei kuang zhenbang Shanghai Jiao Tong Univ Dept Engn Mech Shanghai 200240 Peoples R China

The higher order asymptotic fields at the tip of a sharp V-notchin a power-hardening material for plane strain problem of Mode I arederived. The order hierarchy in powers of r for various hardeningexponents n and notch angles β is obtained. The angulardistributions of stress for several cases are plotted. Theself-similarity behavior between the higher order terms is *** is found that the terms with higher Order can be neglected for theV-notch angle β>45°.

关键词： asymptotic V-notch higher order terms power-hardening

CYCLIC DEFORMATION BEHAVIOR OF ZIRCALOY-4 AT DIFFERENT TEMPERATURES

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Acta Metallurgica Sinica(English Letters) 1995年第3期8卷 219-225页

作者： XIAO Lin GU Haicheng kuang zhenbang(Xi’an Jiaotong University, China Xi'an Jiaotong Univ Xi'an China

Fatigue lifetime curves of Zircaloy-4 at different temperatures were measured, and the fatigued dislocation configurations were investigated using transmission electron microscopy. Ii was found that prismatic slip is the primary deformation mode. for Zircaloy-4fatigued at RT prismatic plus Pyramidal slip at 400℃,and prismatic plus (0001) basic slip at 600℃. The corresponding dislocation configurations are parallel dislocation lines al RT, elongated cells at 400℃ and two sets of mutually Perpendicular dislocation bands at 600℃.respectively. The relationship among. fatigue deformation mode, dislocation configuration and lifetime is discussed.

关键词： Zircaloy-4,.fatigue dislocation configuration slip system

Some variational principles in electroelastic media under finite deformation

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Science China(Physics,Mechanics & Astronomy) 2008年第9期51卷 1390-1402页

作者： kuang zhenbang Department of Engineering Mechanics,Shanghai Jiaotong University,Shanghai 200240,China Department of Engineering Mechanics Shanghai Jiaotong University Shanghai China

It is proposed that the universal thermodynamic energy variational principle is in-cluded in the first law of thermodynamics. Some variational principles in the elec-troelastic media under finite deformation are derived from this universal thermo-dynamic variational principle. It is suggested that in the general electroelastic analysis the environment should be considered together with the discussed elec-troelastic medium. For the variational principle of nonlinear electroelastic media the variation of the electric potential is coupled with the virtual displacement,and the variation of the initial volume should be considered. The Maxwell stress in the initial configuration is naturally derived from this variational principle and it is unique in the second order precision.

关键词： first law of thermodynamics variational principle the electroelastic media the governing equation

PROPAGATION OF SURFACE ACOUSTIC WAVES IN PRESTRESSED ANISOTROPIC LAYERED PIEZOELECTRIC STRUCTURES

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Acta Mechanica Solida Sinica 2003年第1期16卷 16-23页

作者： Liu Hua kuang zhenbang Cai Zhengming Wang Tiejun Wang Zikun Department of Engineering Mechanics Shanghai Jiaotong UniversityShanghai 200240China Department of Engineering Mechanics Xi’an Jiaotong UniversityXi’an 710048China

The propagation of surface acoustic waves in layered piezoelectric structureswith initial stresses is investigated. The phase velocity equations are obtained for electricallyfree and shorted cases, respectively. Effects of the initial stresses on the phase velocity and theelectromechanical coupling coefficient for the fundamental mode of the layered piezoelectricstructures are discussed. Numerical results for the c-axis oriented film of LiNbO_3 on a sapphiresubstrate are given. It is found that the fractional change in phase velocity is a linear functionwith the initial stresses, and the electromechanical coupling factor increases with an increase ofthe absolute values of the compressive initial stresses. The results are useful for the design ofsurface acoustic wave devices.

关键词： surface acoustic waves layered piezoelectric structure phase velocity electromechanical coupling coefficient

A MIXED ELECTRIC BOUNDARY VALUE PROBLEM FOR AN ANTI-PLANE PIEZOELECTRIC CRACK

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Acta Mechanica Solida Sinica 2003年第2期16卷 110-115页

作者： Huang Zhenyu kuang zhenbang (Department of Engineering Mechanics,Shanghai JiaotongUniversity,Shanghai 200240,China) Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

The analytical continuation method is adopted to solve a mixed electric boundary value problem for a piezoelectric medium under anti-plane *** crack face is partly conductive and partly *** results show that the stress intensity factor is identical with the mode Ⅲ stress intensity factor independent of the conducting *** the electric field and the electric displacement are dependent on the electric boundary conditions on the crack faces and are singular not only at the crack tips but also at the junctures between the impermeable part and conducting portions.

关键词： piezoelectric medium fracture mechanics mixed boundary value problem

FRACTAL ANALYSIS OF FRACTURE SURFACE OF WELDED JOINT UNDER LOW CYCLE FATIGUE

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Acta Metallurgica Sinica(English Letters) 1993年第3期6卷 172-178页

作者： NI Yushan CHENG Guangxu kuang zhenbang Xi’an Jiaotong University,China doctorate student,Institute of Engineering Mechanics,Xi’an Jiaotong University,Xi’an 710049,China Xi'an Jiaotong Univ Xi'an China

Hausdorff dimension of fracture surface roughness of welded joint,both welding metal and heat-affected *** pressure vessel steel 16MnR,tested under strain-controlled low-cycle fatigue,was examined with computer vision srstem and by two-dimensional variation method. Results show that it decreases with the increase of cyclic hysteresis *** Hausdorff di- mension variation at heat-affected zone is greater than that of weld *** is believed that the greater the fractal dimension is,the longer the fatigue life will be.

关键词： welded joint low-cycle fatigue fractograph Hausdorff dimension

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波在双孔隙与单孔隙介质界面上的反射与透射

力学学报 2006年第3期38卷 330-338页

作者：代智军赵社戌匡震邦上海交通大学工程力学系上海200240

基于Biot理论和双重孔隙介质理论研究了弹性波在双重孔隙介质与流体饱和单一孔隙介质界面的反射和透射问题,在界面上假定裂缝孔隙流体相对于固体骨架的位移为零,推导了反射系数和透射系数的计算公式,数值讨论了反射系数和透射系数随入... 详细信息

基于Biot理论和双重孔隙介质理论研究了弹性波在双重孔隙介质与流体饱和单一孔隙介质界面的反射和透射问题,在界面上假定裂缝孔隙流体相对于固体骨架的位移为零,推导了反射系数和透射系数的计算公式,数值讨论了反射系数和透射系数随入射角和频率的变化关系．同时,讨论了双重孔隙介质中3种压缩波 (P-1,P-2和P-3波)和一种剪切波(S波)的频散和衰减特性．

关键词：双重孔隙介质频散衰减反射和透射

含界面刚性线夹杂与广义压电位错双压电介质的电弹性分析

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固体力学学报 2008年第3期29卷 223-230页

作者：周志东赵社戌匡震邦厦门大学材料学院材料科学与工程系厦门361005 上海交通大学工程力学系上海200240

研究了双压电材料中广义压电位错与分布于界面的刚性共线线夹杂相互作用问题.基于线性压电理论Stroh框架,相应的混合边值问题,可化为常见的Hilbert问题.求解Hilbert问题,得到存在界面刚性线夹杂与位错时,压电体内所有场变量的显式表达.... 详细信息

研究了双压电材料中广义压电位错与分布于界面的刚性共线线夹杂相互作用问题.基于线性压电理论Stroh框架,相应的混合边值问题,可化为常见的Hilbert问题.求解Hilbert问题,得到存在界面刚性线夹杂与位错时,压电体内所有场变量的显式表达.给出了由于界面和刚性线夹杂的存在,作用于广义压电位错上的广义Peach-Koehler镜像力.对均匀压电材料这一特殊情况,给出了数值算例,讨论了位错对刚性线夹杂端部场强度因子的干涉和它们之间的相互作用.结果可作为求解界面刚性线夹杂与微裂纹交互作用问题的Green函数,也可作为边界元方法的核函数.

关键词：压电材料刚性线夹杂位错场强度因子 Green函数