双止裂孔对疲劳裂纹扩展的影响研究

Effect of double stop holes on fatigue crack propagation

试验采用Q345桥梁钢制作紧凑拉伸试样,并在裂纹前打双止裂孔。通过疲劳裂纹扩展试验,研究双止裂孔对疲劳裂纹扩展速率的影响,探讨其止裂机理。研究发现:双止裂孔能显著增长试样的疲劳寿命,且能获得极低的初始裂纹扩展速率值,对于延长试样寿命,具有重要意义。

In this study,Q345 bridge steel was used to make compact tensile specimen,and double stop holes was made before crack.Through fatigue crack growth test,the effect of double crack stop on fatigue crack growth rate was studied,and the crack stop mechanism was discussed.It is found that the double stop holes can significantly increase the fatigue life of the sample and obtain a very low initial crack growth rate value,which is of great significance for extending the specimen life.