摘要
本文用16 MnR钢的带不同倾斜角中心裂纹的十字形试件研究了1∶2双轴载荷下Ⅰ-Ⅱ复合型裂纹的断裂行为。为了测定高韧性材料Ⅰ-Ⅱ复合型裂纹的扩展方向和裂纹尖端张开位移矢量((?))的启裂值,本文提出了适合于Ⅰ-Ⅱ复合型断裂的多剖面法。所得结果表明,在高韧性材料中裂纹启裂时,CTOD的数值并不是材料的常数,但是,(?)的方向与扩展方向有较好的关联,且其张开型分量与裂纹倾斜角无关,为一与用标准Ⅰ型试件测得的断裂韧性值基本相同的常数。因此,(?)有希望成为高韧性材料Ⅰ-Ⅱ型裂纹的断裂判据。
In the present paper, the fracture behavior of Ⅰ-Ⅱ mixed mode cracks under bi-axial loading of ratio of 1:2 was investigated with cruciform specimens of 16MnR steel containing variously tilted centra] cracks. In order to determine the directions of the propagation and to measure the crack tip opening displacement vector(CTOD) at initiation of Ⅰ-Ⅱ mixed mode cracks in high ductile materials, a multi-sectional method for Ⅰ-Ⅱ mixed mode fracture was proposed. The results obtained showed that, in high ductile materials, the amount ofCTOD at initiation in not a material constant, and that, however, the dire-tions of CTOD are well correlated with those of propagation, and its opening component is a constant independent of the inclination angles which is nearlyepual to the fracture toguhness measured with standard mode I specimens. The-refore, the CTOD could be used as a criterion for Ⅰ-Ⅱ mixed mode cracks inhigh ductile materials.
基金
中国科学院自然科学基金(技85077)
关键词
金属材料
裂纹
张开位移
韧性材料
Ductile fracture, Mixed mode fracture mechanics, Elastic plastic fracture criteria, Crack opening displacement, Biaxial loading, Fracture test.
