高压容器端部法兰开孔的应力分析和强度评定

Stress analysis and strength evaluation of flange opening at the end of high pressure vessel

针对压力容器在开孔区域存在应力局部较高的问题,采用有限元软件ANSYS Workbench17.0对高压容器端部法兰上径向开孔与斜向开孔结构进行应力分析和强度评定,考察了3种开孔组合对法兰整体强度的影响。结果表明:一斜三径法兰的最大等效应力值为282.48 MPa,且一斜三径法兰的一次应力、一次应力加二次应力均低于许用值,开径向孔对法兰强度影响小,工程中应优先选择开径向孔。同一孔径下,一径三斜法兰一次应力值为274.27 MPa,相对一斜三径法兰增加7.33%,开斜向孔对法兰强度的降低较径向孔更为明显。同一承压面积下,增大径向孔孔径后的一径一斜法兰最大等效应力值为321.51 MPa,相对一斜三径法兰增加13.81%,增大径向孔孔径将导致最大等效应力增加,法兰强度降低。

In view of the problem of high stress in the opening area of pressure vessel,the stress analysis and strength evaluation of radial and oblique openings structure on the end flange of high pressure vessel are carried out by using ANSYS Workbench 17.0. The influence of three kinds of opening combination on the overall strength of the flange is investigated. The results show that the maximum equivalent stress value is 282.48 MPa occurred at the flange opening with one oblique hole and three radial hole,and the primary stress,the primary and second stress are lower than the allowable stress.The flange strength is less affected by radial hole, so the radial hole should be preferentially selected in project.Under the same hole diameter, the primary stress of one radial hole and three oblique hole is 274.27 MPa, which is 7.33% higher than that of one oblique hole and three radial hole.The decrease of flange strength by opening oblique hole is more obvious than that of radial hole.Under the same pressure area, the maximum equivalent stress of the flange opening with one radial hole and one oblique hole is 321.51 MPa after increasing the radial hole diameter,which increases by 13.81% compared with one oblique hole and three radial hole flange. Meanwhile, increasing the radial hole diameter will increase the maximum equivalent stress and reduce the flange strength.