(中南工业大学力学开放实验室， 长沙 410083瑞典皇家工学院固体力学系， 斯德哥尔摩 10044， 瑞典
)
摘 要: 滚珠轴承接触点附近的高压剪应力是引起轴承疲劳破坏的原因。 为获得高强度钢在压剪疲劳加载下的断裂性态， 通过轴向裂纹薄壁圆筒的压剪疲劳加载试验， 研究了这类材料的疲劳破坏规律。 结果表明， 复合疲劳加载时门槛值对压应力分量并不敏感， 但对扩散速率和临界扩展角却有明显影响。 裂纹扩展速率随压应力增加而提高， 裂纹较快达到失稳； 裂纹扩散角则随压应力增加而减小， 疲劳裂纹将向有利于Ⅰ型断裂的方向扩展。 这表明轴承滚道内， 任何平行于压应力的缺陷、 微裂纹都将是十分危险的。
关键字: 疲劳断裂 门槛值 应力强度因子 裂纹扩展速率
HIGH STRENGTH STEEL SUBJECTED TO
COMPRESSIVE SHEAR LOADING
（Opening Laboratory of Mechanics, Central South University of Technology, Changsha 410083, P. R. China
Department of Solid Mechanics, The Royal Institute of Technology, Stockholm 10044, Sweden
）
Abstract:High compressive-shear stress beneath the contact point of ball bearing is the main reason for its fatigue failure. In order to obtain the knowledge of compressive-shear fatigue crack growth, thin-wall tube specimens with axial crack are used in the experiments. The specimens are loaded by a cyclic torque combined with different axial compressive stresses. The results show that fatigue crack growth rate and cracking angle are greatly affected by compressive stresses, the crack growth rate increases while cracking angle decreases with the increasing of compressive stresses. The threshold value seems insensative to compressive stresses. The results also show that fatigue crack growth tends to mode Ⅰ fracture and become unstable at higher compressive stresses, which reveals that any microcracks or faults parallel to compressive stress are the most dangerous under fatigue loading.
Key words: fatigue fracture threshold value stress intensity factor crack growth rate
