低周疲劳寿命的试验研究

 用GH33A钢制成圆柱形棒、鼓形平板和带中心孔平板3种试件进行拉-拉低循环试验。试验测定的疲劳寿命与采用局部应力-应变法预测的寿命结果符合较好。随着应力集中系数的增加，试验寿命与预测寿命之比有所增大。实验中，一次超载造成较大的寿命降低。由于较厚板缺口处存在双向应力-应变状态，较厚试件的疲劳寿命比较薄平板的寿命长。

EXPERIMENTAL INVESTIGATION OF LOW CYCLE FATIGUE LIFE

The pull-pull low cycle fatigue test is conducted for various specimens made from GH33A steel. There are three forms of the specimens: the cylindrical bar, the drum-form plate and the plate with a centre circular hole. The fatigue life measured experimentally is compared with one predicted by using local stress-strain approach. As the stress concentration factor is increased, the ratio of test life to predicted life is raised. According to the Miner law,the damage caused by one overload can be neglected. But experimentally an overload results in a considerable reduction in low cycle fatigue life. Owing to two-directional stress-strain status at a notch of the thicker plate, the fatigue life of the thicker specimens is longer than that of thinner plate. In general, the low cycle fatigue life predicted by the local stress-strain approach agrees well with experimental results.