平面应力裂纹尖端复合型弹塑性变形场和约束场的有限元分析  

FINITE ELEMENT ANALYSIS ON THE ELASTIC PLASTIC DEFORMATION AND RESTRAINT FIELD OF A MIXED CRACK UNDER PLANE STRESS CONDITION

作　　者：沙江波[1,2] 邓增杰[1,2] 周惠久[1,2] 

机构地区：[1]广东工业大学材料系 [2]西安交通大学材料科学与工程学院

出　　处：《机械强度》1997年第1期57-61,共5页Journal of Mechanical Strength

基　　金：国家教委博士点基金

摘　　要：应用有限元方法分析了不同Ⅰ＋Ⅱ复合型下裂纹尖端的变形场和约束场（应力三轴性水平Ｒσ分布），结果表明，平面应力条件下复合型裂端变形是不对称的相反塑性变形，符合钝化—锐化模型。Ⅰ＋Ⅱ复合加载时裂端出现负约束的区域（该区Ｒσ＜０），随Ⅱ型分量增加，负约束区域增大，且最大正约束水平Ｒσｍａｘ降低。实际裂端的约束水平及其分布满足ＨＲＲ场所要求的独立于外载荷水平和距裂端距离的性质。平面应力条件下裂端的约束水平远低于相应条件下平面应变时裂端的约束水平。本文亦讨论了复合变形损伤的力学行为。The elastic plastic deformation and restraint field ( R σ ) under different Ⅰ+Ⅱ mode loading for plane stress condition was analysed by FEM.It′s shown that an opposite kinds of deformation occurs at the crack tip of a mixed mode crack under plane stress condition,the deformation model of crack is sharpening blunting.With an increasing of mode Ⅱ loading component,the negative region of restraint field ( R σ<0) exists at crack tip and become large,but the maximum positive restraint level ( R σ ) decreases.The restraint distribution of a mixed crack contained in an actual structure satisfies the HRR character that the restraint level is independent of loading level and distance from crack tip.The restraint level of plane stress is lesser than that of plane strain at the same mixed condition.The mechanical behavior of mixed deformation and damage was also discussed in this paper.

关 键 词：复合型 平面应力 有限元 变形场 约束场 裂纹端 

分 类 号：O346.1[理学—固体力学]