关键词: 过载比, 拉伸过载, 裂纹扩展, 应力比

Abstract: For most engineering components/structures, it is frequent subjected the single tensile overload during constant amplitude loading. The influence of overload ratio, stress ratio and specimen thickness are analyzed and study on the fatigue crack growth behavior and fatigue life after the single tensile overload. A series of fatigue crack growth experiments subjected to a single tensile overload are conducted using compact tension specimens of Q345R steel. The experimental results of single tensile overload show that a larger overload ratio induces the more obvious retardation effect, retardation effect decreased with increased stress ratio, retardation effect decreased with increased specimen thickness. The crack growth shapes of specimens are obtained by using the marking method under overload and constant amplitude loading. The experimental results explain the fatigue crack growth behavior after overload. The crack growth experiment and analyze results is important to the life prediction of engineering components.

Key words: crack growth, overload ratio, stress ratio, tensile overload