摘要
本文总结了微量预应变和超载对低合金高强度钢疲劳性能影响的实验结果.实验结果表明,微量预应变和超载的影响与试件几何有关,对光滑试件产生负效应,而对切口试件产生零效应.对超载效应的机制作了实验研究与分析.讨论了Miner定则适用性及应考虑的因素.
Experiments have been performed to investigate the effects of small prestrain and overloading on the fatigue life and fatigue crack initiation (FCI) life of high strength low alloy (HSLA) steels. Test results show that the effects of prestrain and oveloading on the fatigue life and FCI life of HSLA steels depend upon the geometry of specimens. For the smooth fatigue test specimens, the small prestrain induced by overloading the specimens to the stress equal to yield stress decreases the fatigue life, which is approximately equal to FIC life in long life region, i.e., the small prestrain or overloading induces the negative effect. For the notched specimens, the small prestrain and overloading have no effect on FCI life, i.e., induce zero effect. Therefore, it is necessary to take the interaction between loads in the load spectrum and load sequence effect into account in the life prediction of smooth elements of HSLA steels by using Miner's rule to calculate the accumulative fatigue damage. However, Miner's rule and the FCI life expression of HSLA steels can be used to predict the FCI life of notched elements of HSLA steels without the need of considering the effect of the interaction between loads. It has been observed that the endurance limit of smooth specimens of HSLA steels is approximately equal to the propotional limit, and that the small prestrain decreases both the endurance limit and propotional limit of smooth specimens of HSLA steels. As a result, it may be thought that the negative effect of small prestrain on fatigue life of smooth specimens be attributed to Bauschinger's effect.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
1993年第3期293-298,共6页
Journal of Northwestern Polytechnical University
基金
国家教委博士点基金
关键词
低合金钢
预应变
疲劳寿命
超载荷
high strength
low alloy steel
prestrain
overloading
fatigue life
life prediction
