受压焊接空心球节点高温试验研究

Experimental investigation on compression performance of welded hollow spherical joints in fire

为研究受压焊接空心球节点火灾下的性能,利用高温试验炉,对不同空心球外径和壁厚、钢管外径和壁厚、钢材屈服强度和荷载比的6种受压焊接空心球节点试件进行了高温作用下的试验研究,得到了其在高温下的温度分布、位移特征和破坏形式,并研究了对其极限耐火时间的影响因素;根据欧洲规范,对受压焊接空心球节点高温作用下的性能进行了非线性有限元数值模拟,分析了节点的温度场分布规律和影响因素。通过分析高温作用下节点的位移变化特征,确定了其破坏模式;试验结果和有限元分析结果进行了对比,二者吻合较好。研究结果表明:增大焊接钢管壁厚和降低焊接空心球节点实际承受的荷载可以有效地延长受压焊接空心球节点的极限耐火时间;钢管根部是高温作用下受压焊接空心球节点的薄弱部位。

Six welded hollow spherical joint specimens were tested under fire in fire test furnace to investigate their behavior under high temperature.The main parameters in the tests were the outside diameter and wall thickness of hollow sphere and steel pipe,yield strength of steel material and the load ratio.The distribution and influencing factors of the temperature fields,the displacement characteristics and the failure modes were obtained.The nonlinear finite element numerical simulation was performed on the compression properties of the welded hollow spherical joints under fire with the thermal parameters specified in the Eurocode.The distribution law and influencing factors of the temperature fields were analyzed.By analyzing the displacement variation characteristics of the welded hollow spherical joints under fire,their failure modes were determined.The comparison between numerical analysis and test results show good agreement.It can be concluded that decreasing the load ratio or increasing the thickness of the welded steel pipe can prolong the ultimate fire-resistant duration,and the steel tube root is the weakness of the welded hollow spherical joint under compression in fire.