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总览 评价 孟莉 ， 杨梦豪 ， 李中华 ， 冯淼林 * （ 船舶海洋与建筑工程学院,上海交通大学, 上海, 200240, 中国 ； ） 摘要： 当物理短裂纹从缺口根部扩展时，裂纹的扩展速率呈现"V"字型，随着裂纹长度的增加裂纹的扩展速率呈现出先下降再上升的趋势。本文
孟莉， 杨梦豪， 李中华， 冯淼林*
（
船舶海洋与建筑工程学院,上海交通大学, 上海, 200240, 中国 ； ）
摘要：
当物理短裂纹从缺口根部扩展时，裂纹的扩展速率呈现"V"字型，随着裂纹长度的增加裂纹的扩展速率呈现出先下降再上升的趋势。本文采用塑性修正的应力强度因子幅来描述缺口以及裂纹尖端塑性区对疲劳小裂纹扩展的影响。本文研究了具有不同缺口半径和加载比例1070钢紧凑拉伸试验件。如果考虑缺口塑性区的影响并采用塑性修正应力因子幅，裂纹扩展速率呈现出的"V"字型能够浓缩成一条直线。塑性修正的应力强度因子幅和弹性应力强度因子幅之间的关系成指数形式， 在"V"字型的转折点前后具有不同的拟合方程。
关键词：
物理短裂纹；塑性修正的应力强度因子幅；缺口；V字型
Li Meng， Menghao Yang， Zhonghua Li， Miaolin Feng*
（
School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China； ）
Abstract：
When a physically short crack propagates from a notch root, the crack growth rate shows a "V-shape" behavior, the rate firstly decreases and then increases with the crack growth. In this study, a plasticity-corrected stress intensity factor (PC-SIF) is applied to describe the effects of notch plastic zone and crack-tip plastic zone on the short crack growth in ductile materials under cyclic tensile load. Compact tension (CT) 1070 steel specimens with different notch sizes and loading ratios are examined. The "V-shape" curves of fatigue crack growth (FCG) data can be condensed into straight lines if the PC-SIF range was used due to the consideration of the influence of plastic zone near the notch root. The ratio between PC-SIF range and stress intensity factor (SIF) range can be fitted by exponential equations, and the expressions before and after the turning point of the "V-shape" curves are distinguish difference.
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