单裂纹对自增强厚壁筒的影响研究

Effect of Single Crack on Thick-walled Autofretted Cylinder

分析了无裂纹时厚壁筒的应力计算方法,介绍了裂纹尖端位移外推的数值计算方法,采用Ansys软件研究了径比为1.7、裂纹长度为1 mm的厚壁筒在未自增强施加工作压力、自增强处理与自增强后施加工作压力三种工况下相对于无裂纹厚壁筒时的应力变化规律。并分析了裂纹前缘自由表面的张开位移及裂尖应力强度因子。结果表明:裂纹的存在只影响厚壁筒在裂尖沿扩展方向一定长度范围内的应力大小与分布;经自增强处理后施加工作压力产生在裂纹尖端前缘自由表面处沿厚度方向张开度明显小于未自增强处理,对其尖端应力强度因子与裂纹前缘张开位移值的计算可由前两种工况计算下叠加而成。

The calculation method of stress on crack free thick-walled cylinders is analyzed. The displacement extrapolation method at the crack tip is introduced. Based on Ansys, compared to crack free thick-walled cylinders, the variation of stress in thick-walled cylinders which diameter ratio is 1.7, crack length is 1 mm is researched un- der three operating pressure included non-autofretted, autofretted and after autofretted and opening displacement and stress intensity factor on crack free surface. The results show that the crack only has influence on the stress mag- nitude and distribution with a certain length in the direction on crack growth. Compared to the non-autofretted,the opening in the direction of thick on is obviously less through operating pressure after autofretted. The value of open- ing displacement and stress intensity factor can sum up from two operating pressure.