摘要
研究了从中碳钢圆棒试样的环状预裂纹开始的疲劳裂纹扩展行为,分析了扭转/拉伸复合加载时不同载荷比对弹塑性疲劳裂纹扩展的影响。在高应力水平下,裂纹断口为宏观平坦。无论是简单加载还是复合加载,裂纹扩展速率都可用J积分的指数方程表达。对于同样的J积分范围值,Ⅰ型载荷下的裂纹扩展速率最高,而Ⅲ型载荷下的速率最低。在复合加载条件下的疲劳断口上观察到疲劳条痕同Ⅰ型加载条件下的相同,其间距与裂纹扩展速率相等。
Fatigue crack propagation tests were conducted on a circumferentially pre-cracked round bar of a medium carbon steel under combined torsion and tension. The fatigue fracture surface was macroscopically flat under the conditions of excessive plasticity and the crack propagation rate were expressed as a power function of J integral range for both single and mixed mode. For the same J integral range, the mode Ⅰ propagation rate was the highest and the mode Ⅲ one was the lowest. Striations were observed on the fatigue fracture surface made under mixed mode loading, and their spacing was equal to the crack propagation rate, the same as mode Ⅰ case.
出处
《航空材料学报》
EI
CAS
CSCD
2004年第5期53-56,62,共5页
Journal of Aeronautical Materials
