压电双材料界面钝裂纹附近螺型位错的屏蔽效应与发射条件

研究了压电双材料界面钝裂纹附近螺型位错的屏蔽效应与发射条件.应用保角变换技术,得到了复势函数与应力场的封闭形式解,讨论了位错方位、双材料电弹常数及裂纹钝化程度对位错屏蔽效应和发射条件的影响.结果表明,Burgers矢量为正的螺型位错可以降低界面钝裂纹尖端的应力强度因子(屏蔽效应),屏蔽效应随位错方位角及位错与裂纹尖端距...

SHIELDING EFFECT AND EMISSION CRITERION OF A SCREW DISLOCATION NEAR AN INTERFACIAL BLUNT CRACK IN PIEZOELECTRIC BI-MATERIALS

The shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack in piezoelectric bi-materials is dealt with. Utilizing the conformal mapping technique, the closed form solutions are derived for electric displacement fields and stress fields due to a screw dislocation located near the interfacial blunt crack. The stress intensity factor and critical conditions for dislocation emission are also calculated. The influences of the position of the dislocation and morphology of the blunt crack as well as the electric-elastic properties on the shielding effect and emission criterion are discussed in detail. The results show that positive screw dislocations can reduce the stress intensity factor of the interfacial blunt crack tip (shielding effect). The shielding effect decreases with the increase of dislocation azimuth angle and the distance between the dislocation and the crack tip. The critical loads at infinity and critical remote electric displacement for dislocation emission increases with the increment of the emission angle and the curvature radius of the blunt crack tip, and the most probable angle for screw dislocation emission is zero. The present solutions contain previous results as the special cases.