Crack propagation

In view of improvement of the fitting effect of the threshold area and Paris area and further utility of the testing information, the Paris formula is revised, the crack spreading rate curve is developed reasonably to the fast spreading area, so as to obtain the complete fatigue crack spreading rate curve which can reflect the crack spreading patterns of the material in different areas.

从改进近门槛区与Paris区拟合效果和进一步利用试验信息的角度,对Paris公式进行了修正,合理地延拓裂纹扩展率曲线到快速扩展区,进而得到能够反映材料在不同区域裂纹扩展规律的完整疲劳裂纹扩展率曲线,并通过16MnR钢的试验数据分析和PW—200型客车转向架关键部位的裂纹扩展寿命估算进行了验证。