楔型向错偶极子对界面裂纹尖端场的干涉

Impact of a Wedge Disclination on Tip Fields of an Interfacial Crack

研究了材料中楔型向错偶极子与界面裂纹的弹性干涉效应.运用复变函数方法获得了复势函数和应力场的封闭形式解答,导出了界面裂纹尖端应力强度因子的解析表达式.讨论了向错偶极子的位置、方向和偶臂长度对界面裂纹尖端应力强度因子的屏蔽和反屏蔽效应.结果表明,向错偶极子靠近裂纹尖端时,对应力强度因子的屏蔽或反屏蔽作用非常强烈.向错偶极子的方向存在一个临界值使其对应力强度因子的屏蔽或反屏蔽效应最大.另外,偶臂长度和材料失配对应力强度因子的影响也很大.

The elastic interaction between a wedge disclination dipole and an interracial crack was investigated. The closed form solutions of complex potentials and stress fields to this problem were presented by using complex potential theory. The stress intensity factors at the tips of the crack were also given. The shielding or anti-shielding effect of the wedge disclination dipole upon the stress intensity factors was evaluated. The results indicated that the shielding or anti-shielding effect to the stress intensity factors increased acutely when the disclination dipole approached the tip of the crack. If the center of the dipole was fixed, there always existed a critical value of the angle of the dipole arm in which the shielding or anti-shielding effect to the stress intensity factor was maximal. In addition, the length of the dipole arm and the material mismatch had significant influence on the stress intensity factors.