焊缝建模对T型圆钢管节点轴压承载力计算的影响

Effect of weld modeling on computation of axial compressive strength of circular steel tubular T-joints

钢管结构常用于大跨度空间结构中,一般作为桁架处理,主要受轴向力作用。T型圆钢管节点是常见的一种钢管节点类型,其试验和有限元研究较多。在有限元模型中,存在无焊缝和有焊缝两种建模方式,有研究者指出无焊缝模型会明显低估节点轴向承载力,但也有无焊缝模型所得承载力与试验结果吻合的报告。为探讨焊缝建模对T型圆钢管节点轴压承载力计算的影响,结合不同来源的13组试验记录,分别建立无焊缝和有焊缝节点有限元模型,计算两种模型的轴压承载力。结果表明:无焊缝模型计算的承载力平均只有试验值的85%,有焊缝模型则可达到95%;无焊缝模型在加强弦管边界的情况下,会提高节点计算承载力,因而可能与试验结果一致。T型圆钢管节点轴压承载力的有限元分析应当考虑焊缝影响。

Steel tubular structures are usually used in large span space structures,and generally regarded as axially loaded trusses.The circular steel tubular T-joint is a common joint type.Much experimental and finite element research on T-joints has been published.In finite element models,there are two types: FE models without weld and with weld.Some researchers pointed out that FE models without weld obviously underestimated the joint axial strength,but some other researchers reported that FE models without weld gave good predictions of test results.To investigate the effect of the weld modeling on the axial compressive strength of circular steel tubular T-joints,the FE models without and with weld are created,according to 13 sets of experiment records from different resources.The ultimate load capacities of these two types of FE models are calculated.The results indicate that the average ratio between the FE and the test results is only 85% for the FE models without weld,while the average ratio reaches 95% for the FE models with weld; the load capacities of the FE models without weld may be increased and thus consistent with the test results,when the chord ends are strengthened.Therefore the weld modeling should be considered in FE analyses of axial compressive strength for circular steel tubular T-joints.