钢管柔性法兰轴拉承载力试验及内外角焊缝受力特性分析

Axial Tensile Bearing Capacity Test and Stress Analysis of Internal and External Fillet Weld of Flexible Flange

柔性法兰通过内外两条环向角焊缝与钢管连接。相关技术规范规定了轴拉、偏拉下柔性法兰的承载力计算公式,但未考虑到柔性法兰角焊缝受力的复杂性。开展柔性法兰的轴拉承载力试验研究和相应试件的有限元模拟,考察柔性法兰的轴拉承载力特性,重点研究柔性法兰内外环向角焊缝的受力机理及轴力分担比例。研究表明,轴拉力作用下外焊缝与主管连接处存在较大应力集中;外焊缝为柔性法兰的主要传力焊缝,而内焊缝在传力的同时有效保证了法兰节点的安全稳定;轴拉受力时外焊缝与内焊缝应力比在2.0以上,设计及加工时应特别注意外焊缝的计算及焊接质量,而内焊缝焊脚尺寸可以是外焊缝焊脚尺寸的60%~100%,该研究成果可为柔性法兰及其焊缝设计加工提供参考。

The flexible flange is connected with the steel pipe mainly through the external and internal two circumferential fillet welds.Some technical specifications are given to calculate the bearing capacity of flange connections under axial tension and deflection.However,the stress complexity of flexible flange fillet welds is not considered.The flexible flange tensile bearing capacity experimental study and their finite element simulation of the corresponding flange were carried out to investigate the flexible flange tensile bearing capacity characteristics,and the internal and external fillet weld of the flexible flange fillet stress mechanism and axial force ratio were the key points of this paper.The research showed that a large stress concentration is on the junction of external weld joint and main pipeline under the action of axial tension.The external weld is the main load transfer weld of flexible flange,while the inner weld is at the same time transmitting force,it effectively guarantees the safety and stability of the flange joint.Under axial tensile load,the stress ratio of outer weldline to inner one exceeded2.0,and the special attentions in design and fabrication should be taken for the calculation and quality of the external weld,and the size of the internal weld can be 60%~100% of the external weld foot size.This research results could be referred for the design of flexible flange and its welding seam.