考虑应力集中、表面加工及尺寸三方面影响因素设计10种疲劳试样,进行拉压疲劳试验,得到了不同形式试样的疲劳寿命。应用三参数Weibull分布描述了疲劳寿命分布的特性。试验结果分析表明:同时存在应力集中和表面加工影响的零件,应力集中对疲劳寿命的影响起主导作用;对于缺口试件,纯粹意义上的尺寸效应是不起作用的,危险点周围材料的应力梯度是造成尺寸效应的关键。
10 kinds of fatigue specimens were designed considering influence factors of stress concentration, machined surface and size effect. The fatigue life of different form specimens were obtained after repeated tension and compression tests, and its dispersion described by three--parameter Weibull distribution. Fatigue test results indicate that, the stress concentration plays a leading role when stress concentration and machined surface affect parts' fatigue life simultaneously. For the notched specimen, it is stress gradient around material danger point causes the size effect.