In this paper, the plastic component of the crack-tip opening displacement (CTOD_p) is experimentally evaluated to characterize the fatigue crack growth behavior in a Grade 2 titanium sample under single overload with constant amplitude loading conditions. The CTOD measurements were performed with the 2D-Digital Image Correlation (DIC) technique. The experimental results show a linear correlation between CTOD_p and fatigue crack growth rates, suggesting the independence of this relationship to load-interaction effects. Therefore, this study demonstrates that the CTOD_p can be a suitable crack-driving parameter to study crack propagation behavior under variable amplitude loading. Furthermore, it suggests that the fatigue crack growth process is primarily caused by cyclic plastic deformation.

在本文中，通过实验评估裂纹尖端张开位移 (CTOD _{p ) 的塑性分量，以表征 2 级钛样品在单一过载和恒定振幅加载条件下的疲劳裂纹扩展行为。}CTOD 测量是使用 2D 数字图像相关 (DIC) 技术进行的。实验结果表明 CTOD _p与疲劳裂纹扩展速率之间存在线性相关性，表明这种关系与载荷交互作用无关。因此，本研究表明 CTOD _p可以是研究变幅载荷下裂纹扩展行为的合适裂纹驱动参数。此外，这表明疲劳裂纹扩展过程主要是由循环塑性变形引起的。