摘要
本文根据国标GB6398-86,采用逐级降载法求出了在不同应力比R条件下,09CuPCrNi钢母材、焊缝和热影响区金属的疲劳裂纹扩展门槛值△K_(th)的表达式。发现,当应力比R达到某一值R_(C.th)之前,母材,焊缝和热影响区的门槛值△K_(th)随着应力比R的增大而减小;当R超过R_(C.th)之后,其门槛值均保持不变。文中还重点叙述了裂纹闭合应力强度因子K_(cl)的计算方法,证实焊接接头的闭合效应远高于母材金属,并对上述规律作了分析和解释。
The expressions of threshold value △K_(th) of fatigue crack propagation in parent,Weld and heat af- fected zone(HAZ)for 09CuPCrNi steel under various values of stress ratio R have been obtained respectively using by gradual down load technique according to Chinese Standard GB6398-86.It is found that threshold values in the three parts would be reduced with incresing stress ratio R as R≤R_(c.th).Whereas their threshold values would be constant as R>R_(c.th).Meanwhile a calculating method for stress intensity factor K_(cl) of crack closure has been described in detail.It is also indicated that the closure effect of welded metal is greater than that of parent metal and the analysis and explanation for this viewpoint have been carried out.
出处
《大连铁道学院学报》
1992年第3期74-79,共6页
Journal of Dalian Railway Institute
基金
国家自然科学基金
关键词
应力比
疲劳
裂纹
门槛值
钢
焊接
weld region
stress ratio
fatigue cracks/threshold value
09CuPCrNi steel
