摘要
研究了Ⅱ、Ⅲ型过载对Ⅰ型疲劳裂纹扩展行为的影响并与Ⅰ型过载进行比较.结果表明:单周Ⅱ、Ⅲ型过载也延迟了其后的Ⅰ型疲劳裂纹扩展,但作用程度小于Ⅰ型过载;过载延迟效应随过载时基础载荷的降低和过载比的加大而增强,在近门槛区过载表现为疲劳裂纹扩展停止、疲劳门槛提高,在高基础载荷过载时疲劳裂纹则延缓、减速扩展.过载延迟行为主要由裂尖尾迹塑性诱导裂纹闭合和裂尖附近残余压应力状态引起.
The effects of Modes II and III overloading on Mode I fatigue crack propagation were studied and compared with Mode I overloading. The results show that, single Mode II or III overloading also retards the subsequent Mode I fatigue crack propagation, and the retarding extent is less under Modes II and III overloading than under Mode I overloading. The retardation effect of overload enhances with decreasing Mode I baseline-load and increasing overload ratio, fatigue crack propagating arrests and fatigue threshold value increases at overloading in the near-threshold regime, fatigue crack propagating retards and decelerates at overloading at higher baseline-load. The overloading retardation behavior is resulting from the crack closure induced by wake zone plasticity and the compressive residual stress around the crack-tip.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第8期843-847,共5页
Acta Metallurgica Sinica
基金
国家自然科学基金资助项目 59871056
关键词
过载
疲劳裂纹扩展
疲劳门槛
延迟
overload
fatigue crack propagation
fatigue threshold
retardation
