向错偶极子对楔型裂纹尖端场的干涉效应  

IMPACT OF A WEDGE DISCLINATION DIPOLE ON TIP FIELDS OF A WEDGE CRACK

作　　者：郭道强[1] 刘又文[2] 

机构地区：[1]郴州强旺新金属材料有限公司,湖南郴州423500 [2]湖南大学力学与航空航天学院,长沙410082

出　　处：《力学与实践》2010年第1期16-19,15,共5页Mechanics in Engineering

基　　金：国家自然科学基金资助项目(10872065,50801025)

摘　　要：研究了材料中楔型向错偶极子与楔型裂纹的弹性干涉问题.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,导出了楔型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、方向和偶臂长度对楔型裂纹尖端应力强度因子的屏蔽和反屏蔽作用规律.研究结果表明,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.在一定条件下,楔型向错偶极子能够延缓楔型裂纹的扩展;偶极子的方向也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.此外,楔型裂纹张开角以及偶极子臂长对应力强度因子也有较大的影响.The elastic interaction between a wedge disclination dipole and a wedge crack is investigated.The closed form solutions of complex potentials and stress fields are obtained by using complex potential theory. The stress intensity factor at the tip of the wedge crack is also obtained.The shielding or anti-shielding effects of the wedge disclination dipole on the stress intensity factor is evaluated.The results indicate that the shielding or anti-shielding effects on the stress intensity factor increase sharply when the wedge disclination dipole approaches the tip of the crack.Under certain conditions,the disclination dipole may weaken the stress intensity near the crack tip.If the center of the dipole is fixed,there always exists a critical value of the angle of the dipole arm for the shielding or anti-shielding effects to be maximal.In addition,the wedge angle of the crack and the length of the dipole arm have a significant influence on the stress intensity factor.

关 键 词：向错 楔型裂纹 应力强度因子 复变函数方法 

分 类 号：O343.7[理学—固体力学]