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业己证明,疲劳裂纹扩展的断裂模型以及根据这一模型导出疲劳裂纹扩展公式:da/dN=B(△K-△K_(th))~2,可用于描述疲劳裂纹扩展机制为:微孔连接、显微解理和晶间分离等机制的金属中的疲劳裂纹扩展过程。本文用实验结果进一步证明,疲劳裂纹扩展的断裂模型以及据此导出疲劳裂纹扩展公式,也可用于描述疲劳裂纹以条带机制扩展的金属中的疲劳裂纹扩展,因而可以认为是普遍适用的。公式中的常数 B,在疲劳裂纹以条带机制扩展的合金中,可根据杨氏模量 E 计算:B=1/[2π(0. 1E)~2] 。实验结果还表明,根据上述公式对疲劳裂纹扩展的实验数据进行回归分析,可以求得精确的疲劳裂纹扩展门槛值△K_(th)。这是一种确定△K_(th)值的新方法,不需要专门的实验,可节约时间和经费。
It has been shown that the fracture model of fatigue crack propagation and the fatigue crack propagation formula derived from this model: da / dN = B (△ K- △ K th (th)) ~ 2 can be used to describe the fatigue crack growth mechanism as: Fatigue crack propagation in metals such as connection, micro-cleavage and intergranular separation. The experimental results further prove that the fracture model of fatigue crack growth and the derived fatigue crack growth formula can also be used to describe the fatigue crack propagation in the fatigue crack growth metal. Therefore, it is generally accepted. The constant B in the formula can be calculated from the Young’s Modulus E in an alloy with fatigue crack growth by a banding mechanism: B = 1 / [2π (0.1E) ~ 2]. The experimental results also show that based on the above formula, fatigue crack growth experimental data regression analysis can be obtained accurate fatigue crack growth threshold △ K th (th). This is a new way of determining the value of ΔK_ (th), which saves time and money by eliminating the need for specialized experiments.