工业结构钢疲劳极限的断裂力学研究

The study on fatigue limit of industrial structural steel with fracture mechanics

文章提出一种预测材料疲劳极限的简便方法。该方法仅需获得一个材料参数(如材料硬度)便可确定材料的裂纹扩展抵抗阻力曲线。由于有效应力强度因子范围门槛值ΔKeffth∞是一个与裂纹长度及应力比无关的材料常数,只需将裂纹张开应力强度因子门槛值Kopth表示为裂纹长度的函数,作出材料的疲劳断裂曲线,就可以预测任意应力比下光滑试样的疲劳极限。利用这种方法作出的预测值与试验结果一致。

Through a large amount of experimental study, a simplified method is proposed to predict the fatigue limits of material in this article. In the method, the crack resistance curve can he determined by using only one material data, such as hardness. Because the threshold value of effective stress intensity range can be considered as a material constant, which is irrespective of crack length and stress ratio, just expressing the threshold value of crack opening stress intensity factor as the faction of crack length, and making the material fatigue fracture curve, then the fatigue limits of the smooth specimen can be predicted under any stress ratio. The predicted values agreed well with the experimental results.