基于焊缝模拟的圆钢管K型、T型节点承载力分析

ANALYSIS OF BEARING CAPACITY OF K-JOINT AND T-JOINT BASED ON WELDING SIMULATION

通过焊材材性试验得到焊材本构模型,分别建立不考虑焊缝模拟、焊缝采用壳单元模拟、焊缝采用实体单元模拟的圆钢管K型及T型节点有限元分析模型,进行节点的有限元分析,并与已有文献试验结果进行对比分析。结果表明：采用实体单元模拟焊缝,节点破坏模式和承载力更接近试验结果,均是支管局部破坏和主管管壁破坏。将焊材和母材材性区别考虑进行焊缝模拟得到的节点承载力值更接近试验值。同时,区别焊材与母材材性建立的有限元模型分析表明：K型搭接节点隐藏焊缝焊接以及隐藏焊缝不焊接时贯通支管受拉将影响节点破坏模式。采用上述分析得到的最优有限元分析模型进行K型搭接节点参数分析,并拟合得出考虑节点参数影响的4类搭接节点承载力计算式,通过试验值校验后发现吻合程度良好。

The constitutive model of welding material was obtained through welding material test,then the finite element analysis models of K-joint and T-joint of circular hollow section（CHS） were established for joints finite element analysis,which including three types of welding models were regardless of the welding simulation,using shell element for welding simulation and using solid element for welding simulation respectively. The results were compared with the test results from literatures. The results indicated that the failure mode and bearing capacity of joints using solid element for welding simulation were more close to experimental results,and the damage occurred in the end of branch member near to the chord member or tube wall of chord member in the simulating model,local failure of branch and plastic failure of chord wall. Considering the difference of material properties between weld seam and base metal a more closer result to experiment results could be obtained. Meanwhile,the analysis of finite element model considered the difference of material properties between welding and base metal showed that the welded hidden welds in overlapped K-joint and the absence of hidden welds with through-brace-in-tension had influence on failure mode of joints. Based on the optimal finite element analysis model,the parameter analysis of overlapped K-joint was carried out,and the calculation formulas of bearing capacity of four kinds of overlapped K-joint considering the influence of joint parameters were fitted,which agreed well with experimental results.