循环载荷下韧性金属Ⅰ型裂纹前缘晶体塑性与应力的初步分析  

ANALYSIS ON CRYSTAL PLASTICITY AND STRESS AT MODE-Ⅰ RACK TIP OF A DUCTILE METAL UNDER CYCLIC LOADING

作　　者：张克实[1] 耿小亮[1] 郭运强[1] 余海东[1] 张光[1] 

机构地区：[1]西北工业大学工程力学系,西安710072

出　　处：《机械强度》2004年第z1期8-11,共4页Journal of Mechanical Strength

基　　金：国家自然科学基金资助项目 (1 9972 0 55)~~

摘　　要：为探讨含裂纹金属材料在循环载荷下的细观力学行为 ,采用随机构成的多晶模型对循环载荷下Ⅰ型裂纹裂尖前缘的晶体塑性变形和应力循环进行初步分析。模型裂尖前缘的材料由不同大小和不同取向的多面体单晶晶粒随机集合构成 ,各晶粒的力学行为用单晶滑移的粘塑性关系描述 ;单晶滑移粘塑性本构关系的求解是采用先前建议的方法 :以应力为基本变量 ,用Newton Raphson迭代求解晶体的滑移变形与应力的关系。文中给出循环载荷下裂尖前缘的塑性变形演化。In order to investigate the meso-mechanical behavior of crack containing metallic materials under cyclic loading, the primary analysis on crystal cyclic plasticity and stress of crystal grains at mode-Ⅰ crack tip for copper material under cyclic tension-tension loading has been carried out. The analysis takes a multi-crystal model that is very small coin-shape section which contains the crack tip and consists of 171 orientation randomly arranged polyhedron crystal grains and its loading is determined by K-dominant far-field. The anisotropic mechanical behavior of the crystal grain is described by single crystalline visco-plastic slipping constitutive model. To obtain the solution of crystal plastic strain and stress in the area around the crack tip, finite element method is applied and the constitutive relation calculation is performed by using an incremental algorithm with Newton-Raphson iteration, which is correlative to current configuration with respect to global coordinate axes. According to the numerical results the anisotropic crystal slipping, residual stress, and cyclic hardening at the mode-Ⅰ crack tip of a multi-crystal material have been discussed.

关 键 词：Ⅰ型裂纹 裂尖前缘 晶粒结构 各向异性 晶体塑性 循环载荷 

分 类 号：O346.1[理学—固体力学] TG111.8[理学—力学]