B型套筒修复管道的极限轴向承载力预估方法

Prediction method of the ultimate axial bearing capacity of B sleeve

含环焊缝缺陷的管道采用B型套筒修复后的极限轴向承载能力至关重要。若依靠试验获得大直径管道修复后的极限轴向承载力,或代价昂贵,或因加载设备的载荷限制而难以实施,文章提出采用品字形焊接板预测其极限轴向承载力的方法。首先,选取两段Φ219 mm的管子对接,模拟环焊缝完全断开的管道。经B型套筒修复后,通过“以压代拉”试验获得极限轴向承载力。同时,进行有限元模拟,试验与模拟结果相差仅2.8%。进而,采用同样的有限元建模方法,获得B型套筒修复Φ1016 mm管道后的极限轴向承载力。最后,针对Φ1016 mm管道的B型套筒修复结构,分析其轴对称性及品字形焊接板承受拉伸时的边界效应,开展品字形焊接板拉伸试验。结果表明,品字板法预估值与有限元模拟值仅相差3.1%。综合模拟与试验结果,品字形焊接板可以准确预估B型套筒修复含环焊缝缺陷管道后的极限轴向承载力。

The ultimate axial bearing capacity of the pipeline with circumferential weld defects repaired with B-type sleeve is very important.Yet it is difficult to obtain the ultimate axial bearing capacity of large-diameter pipes by experiment,either too expensive or load limitation of testing machine,and a method of using the pyramid structure welded by three plates to predict its ultimate axial bearing capacity is proposed.First,dock twoΦ219 mm pipes to simulate a pipe with a completely cracked circumferential weld.Repair the pipes with B sleeve,and obtain its ultimate axial bearing capacity through the“pressure turns to tension”test.Simultaneously,carry out the corresponding finite element simulation,and the deviation between experiment and simulation is only 2.8%.Furthermore,adopt the same finite element modeling method to obtain the ultimate axial bearing capacity of theΦ1016 mm pipe repaired with B sleeve.Ultimately,targeting the B sleeve repair structure of theΦ1016 mm pipe and considering its axial symmetry and the boundary effect of the pyramid structure welded by three plates when it is stretched,a tensile test of the pyramid structure welded by three plates is carried out.The results show that the difference between the predicted value of the pyramid structure welded by three plates method and the finite element simulation value is only 3.1%.Synthesizing the simulation and test results,the prediction method of the pyramid structure welded by three plates can accurately estimate the ultimate axial bearing capacity of the pipeline with circumferential weld defects repaired with B-type sleeve.