摘要
P92钢蒸汽管道焊接接头中易出现裂纹等缺陷,严重威胁着超超临界机组的安全运行,采用ANSYS Workbench软件建立了焊接接头中两半椭圆表面裂纹的有限元模型,并研究了两裂纹间距和次裂纹尺寸对主裂纹前缘应力强度因子的影响规律。研究结果表明,对于两共面的轴向裂纹和两共面的环向裂纹,次裂纹的存在增大主裂纹前缘的应力强度因子,而对于两非共面的轴向裂纹和两非共面的环向裂纹,次裂纹的存在则减小主裂纹前缘的应力强度因子,且这种作用随两裂纹间距的减小或次裂纹尺寸的增大而增强。对于中心连线与轴线平行的轴向与环向裂纹,当形状因子a/c=0.4时,环向裂纹的存在对轴向裂纹前缘应力强度因子的影响不大;但轴向裂纹的存在却增大环向裂纹前缘的应力强度因子,且这种作用随两裂纹间距的减小或轴向裂纹尺寸的增大而增强。当a/c=1.0时,一条裂纹的存在增大另一条裂纹前缘的应力强度因子,且这种作用随两裂纹间距的减小而略有增强;增大环向裂纹尺寸,其增大轴向裂纹前缘应力强度因子的作用略有增强;轴向裂纹尺寸对环向裂纹前缘应力强度因子的影响则取决于两裂纹间距。
The defects,such as cracks,easily form in welded joint of a steam pipe made of P92 steel,which are a serious threat to the safe operation of ultra supercritical units. In this study,ANSYS Workbench software was used to establish the finite element models of two semi-ellipse surface cracks in welded joint of a steam pipe made of P92 steel,and the influence of the spacing of the two cracks and the size of the subordinate crack on the stress intensity factor（ SIF） at the tip of the main crack was investigated.The results show that for two coplanar axial or circumferential cracks,the SIF at the tip of the main crack increases due to the existence of the subordinate crack. However,for two non-coplanar axial or circumferential cracks,the SIF at the tip of the main crack decreases due to the existence of the subordinate crack.This effect increases with the reduction in the spacing of the two cracks or the increase in the size of the subordinate crack. For an axial and a circumferential crack（ the line through their center is parallel to the axial direction of the steam pipe）,when the shape factor a/c = 0. 4,the existence of the circumferential crack has little effect on the SIF at the tip of the axial crack. But the SIF at the tip of the circumferential crack increases due to the existence of the axial crack,and this effect increases with the reduction in the spacing of the two cracks or the increase in the size of the axial crack. When a/c = 1. 0,the SIF at the tip of the axial（ or circumferential） crack increases due to the existence of the circumferential（ or axial）crack,and this effect increases slightly with the reduction in their spacing. The SIF at the tip of the axial crack increases slightly with the size of the circumferential crack. The variation of the SIF at the tip of the circumferential crack with the size of the axial crack depends on the spacing of the two cracks.
出处
《压力容器》
2017年第8期57-65,共9页
Pressure Vessel Technology
关键词
P92钢蒸汽管道
焊接接头
裂纹
应力强度因子
有限元分析
steam pipe made of P92 steel
welded joint
crack
stress intensity factor
finite element analysis
