摘要
用云纹法和光学空间滤波技术测量了双边裂纹单向拉伸的４种不同硬化指数铝 试件扩展裂纹尖端三维位移场；分析了位移奇异性；与ＧＨ理论解进行了比较。给出了 Ｉ型、平面应力、幂硬化材料扩展裂纹尖端奇异场比较的形式。证明和确定了试验的 ＧＨ奇异场主导区的存在及其范围和形状。ＧＨ主导区的尺寸和形状与材料特性、试件 几何尺寸和外载形式有关。在ＧＨ场内裂纹尖端附近有三维变形损伤区，该区内不是ＧＨ 奇异性．紧靠裂纹尖端有一个断裂过程区。随着外载荷增加将随机地出现孔洞并导致裂 纹扩展。
The displacement fields ux,uy,in x, y directions at growing crack tip of the specimens with double edge cracks for four different alumium alloys are measured using moire method and optical spatial filtering technique. From experimental displacement fields, the displacement singularity fields are obtained and compared with GH theoretical field. Unknown constants A and εyo in theoretical solution are determined from experimental data. The theoretical singularity field thus compared is given for plane-stress, mode-I, strain-hardening materials. The error in both the experimental and theoretical evaluations is within±10% The experiments show that there exists [In (A/r)] a +1 dominant singularity region around a growing crack-tip. In the experiments, the strain hardening index n amounts from 3.158 to 6.500. The shape of this dominant region ranges from butterfly wing to oblate or circular shape. The size and shape of GH dominant region depend on the material property, the specimen geometry and loading type. Inside GH-field, there is 3-D deformed damage zone, where no GH singularity exists. Very near to the crack-tip, there is a fracture process zone.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
1992年第2期58-66,共9页
Journal of Tsinghua University(Science and Technology)
关键词
韧性材料
裂纹尖端
奇异场
损伤区
singularity field, damage zone, crack tip, optical filtering technique
