B780CF钢焊接接头疲劳裂纹扩展速率可靠性研究

对B780CF钢在不同的焊接工艺下疲劳裂纹扩展行为进行试验,研究其概率疲劳规律。采用七点递增多项式拟合方法,计算了一系列不同焊接工艺下相同裂纹长度存活率分别为50%、90%、95%、99%、99.9%的裂纹扩展速率,得到了不同焊接工艺下疲劳裂纹扩展速率曲线及表达式。定量分析了在不同可靠度下焊接工艺对疲劳裂纹扩展速率及Paris公式中两个重要参数的影响。

STUDY ON RELIABILITY OF FATIGUE CRACK GROWTH RATE OF B780CF STEEL WELDED JOINT

The fatigue crack growth rates of B780CF steel under different welding process are studied.The crack growth rate where the survival rates are 50％,90％,95％,99％ and 99.9％ are calculated with the same crack length by the seven point incremental polynomial fitting method.The fatigue crack growth rate curves and expressions under different welding process are obtained.The effect of welding process on fatigue crack growth rate and two important parameters in Paris formula are analyzed under different reliability.