Q355钢疲劳寿命预测的新应力函数模型

A new stress function model for fatigue life prediction of Q355 steel

室温下,对Q355钢进行应力控制下的单轴拉压疲劳实验,讨论了应力比和峰值应力对应力疲劳寿命的影响。应力比的增大和峰值应力的减小都会导致疲劳寿命的增大,发现同一应力比下,峰值应力和对数疲劳寿命呈良好线性关系,该线性关系可以用于Q355钢疲劳寿命的预测。探究发现应力比对线性关系中斜率和截距的影响显著,提出了一个关于应力比的新的应力函数预测模型,将新模型的预测结果与传统的Morrow、SWT和Paul模型的预测结果进行比较,结果表明:新应力函数模型的预测结果比Morrow、SWT和Paul模型更精确且更稳定,新的应力函数模型更适合于Q355钢的多应力比多峰值应力下的疲劳寿命预测。

The uniaxial fatigue tensile and compression test under stress control was carried out on Q355 steel at room temperature,and the effect of stress ratio and peak stress on the fatigue life was discussed.The fatigue life increases with the increase of stress ratio and the decrease of peak stress.The research shows that the peak stress has a good linear relationship with the logarithmic fatigue life at the same stress ratio,which can be used to predict the fatigue life of Q355 steel.The research shows that stress ratio has a significant effect on slope and intercept in linear relationship.A new stress function prediction model of stress ratio was proposed.The prediction results of the new model were compared with those of the traditional Morrow,SWT and Paul models.The results show that the prediction results of the new stress function model are more accurate and stable than those of Morrow,SWT and Paul models,and the new stress function model is more suitable for the fatigue life prediction of Q355 steel under multi-stress ratio and multi-peak stress.