柔性法兰节点轴拉承载力试验及盘面变形计算

Axial Tensile Bearing Capacity Test and Flange Plate Deformation Calculation of Flexible Flange Joints

柔性法兰是一种构造简单、盘面平整的钢管连接节点形式,通过内、外两道环向角焊缝传力。研究了柔性法兰节点轴心受拉承载力特性,以法兰盘厚度为参数,开展柔性法兰轴拉承载力试验研究,考察了柔性法兰盘面变形特点及节点应变发展规律,发现增大法兰盘厚度可使柔性法兰轴拉屈服承载力提高约15%。建立柔性法兰的非线性有限元模型,分析了轴拉作用下柔性法兰的变形特性及法兰盘和内、外角焊缝的应力分布及发展情况。分析结果表明:法兰盘根部内缘张开,外缘顶紧,盘面中部应力最大,与试验结果吻合良好。最后,提出轴心受拉柔性法兰盘面变形计算方法,建议法兰盘根部变形修正系数取1.4,提出的盘面变形计算公式可供柔性法兰设计时参考。

The flexible flange is a form of steel pipe joint with simple detail and flat surface.It transfers force through two inner and outer circumferential welds.The axial tensile bearing capacity of flexible flange joints is studied in this paper.With the flange plate thickness as a parameter,the deformation characteristics of flange plate and the development of joint strain are investigated.Increasing the flange thickness can increase the axial tensile yield strength of flexible flange by about 15%.A nonlinear finite element model of the flexible flange is established,and the deformation characteristics of flexible flange and the stress distribution and development of flange plate and inner and outer welds are analyzed.The results show that the inner edge of the flange plate is open,the outer edge is tight,and the stress in the middle of the plate is the largest,which is in a good agreement with the corresponding test results.At last,the deformation calculation method of flexible flange under axial tension is proposed.It is suggested that the correction coefficient of the deformation of the flange is 1.4,and the calculation formula for the deformation of flange plate can be used as a reference for the design of flexible flanges.