Effect of Specine Width on Fatigue Crack Growth Rate in Steels.

一般来说，疲劳被认为是结构失效的主要原因。由于多种因素的影响，疲劳裂纹扩展速率具有随机性。研究考虑了影响钢疲劳裂纹扩展的主要因素，即试样宽度W、长径比a/W和应力比r。采用恒定DELTAK水平下的BS4360钢的CT（致密拉伸）试样进行了试验。采用有限元法进行了二维弹塑性分析。试验和计算结果表明：(1)试样宽度减小，疲劳裂纹扩展速度加快；(2)高长径比时，疲劳裂纹扩展速率略有提高。(3)应力比加速了疲劳裂纹扩展速率。

Generally, fatigue is known as the main cause of structural failures. Fatigue crack growth rate is random due to various factors.The investigation was carried out taking into account the main factors that are believed to most affect fatigue crack propagation in steels, namely specimen width W,aspect ratio a/W,and the stress ratio R.Experimental tests were conducted with CT (compact tension) specimens made of BS4360 steel under constant DELTAK level. Two dimensional elastic-plastic analysis using finite element method were also performed.This study (both tests and calculations) demonstrated that :(1) Fatigue crack growth rate is accelerated by decreased specimen width.(2) Fatigue crack growth rate is increased marginally at high aspect rations.(3) Fatigue crack growth rate is accelerated by stress ratio.