压电材料中螺型位错和偶极子与半椭圆槽表面裂纹的干涉效应

运用弹性复势方法,研究纵向剪切和面内电场共同作用下无限半平面压电材料中螺型位错和偶极子与半椭圆槽表面裂纹的电弹干涉效应,得到该问题复势函数的封闭形式解答,并由此导出广义应力场、裂纹尖端的广义应力强度因子以及作用在螺型位错上的位错力.算例结果表明:增大材料压电常数会相应增大位错力、位错对裂纹尖端的屏蔽和反屏蔽效应；增大位错离裂纹尖端的距离,位错力会相应减小；变化φ(偶极子臂与x轴正半轴夹角)值会出现一个改变位错偶极子对应力强度因子作用方向的临界值.

INTERACTION BETWEEN A PIEZOELECTRIC SCREW DISLOCATION AND DIPOLE AND A SEMI-ELLIPTICAL GROOVE SURFACE CRACK IN PIEZOELECTRIC SOLIDS

By using the complex variable method,research the interaction of a piezoelectric screw dislocation dipole in the infinite half-plane with a semi-elliptical blunt cracks under remote anti-plane shear stresses and in-plane electric loads,the general solutions to the problem are obtained,the complex potentials,the generalized stress fields,the intensity factors of stress in the crack tip and the image force acting on the dislocation dipole center are also calculated.The numerical results show: increase of piezoelectric material constants can increase the dislocation force accordingly,the shielding /reverse shielding effect of the crack tip,increasing the distance of dislocation and the crack tip can reduce the dislocation force accordingly,change φ(the angle of dipole arm and x-axis)will appear a critical value that can change the direction of stress intensity factor.