根据裂纹尖端范性钝化临界条件的分析和应力比R对金属疲劳裂纹扩展的影响,得出计算应力强度因子范围门坎值的一般公式: △K_(th)=Eε_f((2πρ_(min))~(1/2))(1—R)~γ 式中ρ_(min)为柏氏矢量的绝对值,|B|,由上式得到的计算值与实验结果是基本相符的。 According to the analysis of critical tip passivation conditions and the effect of stress ratio R on the fatigue crack propagation, a general formula for calculating the threshold value of the stress intensity factor is obtained: △ K th = Eε f (2πρ min) ~ (1/2)) (1-R) ​​~ γ where ρ_ (min) is the absolute value of the Bollinger vector, | B |, and the calculated value obtained from the above formula basically agrees with the experimental result.