韧性材料复合型断裂启裂点与开裂方向的讨论  

DISCUSSION FOR THE POINT OF INITIATION BREAK AND THE DIRECTION OF CRACK GROWTH IN MIXED MODE FRACTURE OF DUCTILE MATERIALS

作　　者：汤安民[1] 师俊平[1] 卢智先[2] 

机构地区：[1]西安理工大学工程力学系,西安710048 [2]西北工业大学工程力学系,西安710072

出　　处：《机械强度》2002年第2期266-269,共4页Journal of Mechanical Strength

基　　金：陕西省自然科学基金资助项目 (2 0 0 0C2 8)

摘　　要：参照多种材料常规断裂结果的宏观分析 ,通过研究LY12材料在不同复合比载荷下的断裂试验结果 ,修正了一般断裂试验中认定裂纹启裂方向的方法 ,结合不同复合比下裂尖附近应力三维度场、主应力方向的计算分析 ,得到 :在裂端的钝化变形区域、应力三维度的极大值处 ,对应于裂纹的启裂位置 ,即使韧性材料Ⅱ型裂纹发生剪切断裂的情况下也是如此 ;裂纹的启裂方向在拉伸断裂时与启裂点最大拉应力方向有关 。To refer the results of macroscopic analysis for conventional fracture of several materials and study the fracture test results under different mixed mode loading for LY12 material, the method of determining the direction of crack initiation growth in common fracture test is corrected. Combined the compute and analysis about the stress tri axicity and the directions of the principal stresses nearby the crack tip bearing different mixed mode loading, it could be concluded that: (1) The position of crack initiation growth is at the place of maximal value of stress tri axicity in the blunted zone of deformation near crack tip even if crack produce mode Ⅱ shear break in ductile material. (2) The direction of crack initiation growth is related to the direction of maximal tension stress at the point of initiation break for tension break. (3) The direction of crack initiation growth is related to the direction of maximal shear stress at the point of initiation break for shear break.

关 键 词：韧性材料 复合型断裂 启裂点 开裂方向 脆性拉断 塑性剪断 应力三维度 

分 类 号：O346.1[理学—固体力学] O346.4[理学—力学]