铝合金板式节点网壳稳定承载力试验研究

为研究铝合金板式节点刚度对单层球面网壳整体稳定性能的影响，制作一个跨度为8m、矢高为0.5m的K6型网壳模型，对网壳顶点施加4次单向循环荷载。试验结果表明，加载初期网壳表现出超刚性特征，即其刚度大于刚接节点网壳刚度；而后的节点螺栓滑移变形会降低网壳刚度，螺栓滑移引起的网壳变形很大且不可恢复。网壳的失稳属于整体跳跃失稳，但网壳屈曲后可继续承载，且荷载可进一步增大。最后一次单向循环加载时网壳因顶点杆件下翼缘的拉裂而破坏。另外，随着循环荷载逐级增大，网壳再加载初始刚度都有一定弱化。采用ANSYS有限元软件建立网壳分析模型，采用BEAM 188单元和COMBINE 39单元模拟考虑节点半刚性的铝合金板式节点网壳杆件，节点弯矩-转角关系曲线采用四折线模型，有限元分析结果与试验结果吻合较好。

Experimental study on buckling capacity of aluminum alloy gusset joint dome

To investigate the influence of aluminum alloy gusset (AAG) joint stiffness on the buckling behavior of single-layer reticulated domes, a K6 dome with 8m span and 0.5m height was designed. The test dome was subjected to unidirectional cyclic load at central joint. It is found that the dome exhibits a super rigid behavior initially, indicating that its stiffness is higher than that of a shell with rigid joint. However, the joint deformation caused by bolt slipping could weaken the shell stiffness, and the shell deformation caused by bolt slipping is large and unrecoverable. The dome buckling belongs to the snap-through buckling, resulting in the larger shell bearing capacity of the post-buckling phase. The dome is collapsed by the fracture of the bottom flange of members near the loading joint at last. In addition, the dome initial stiffness is decreased in the order of the unidirectional cyclic loading process. The FE dome model was established in the ANSYS program, with its element simulated using BEAM 188 and COMBINE 39, considering the four-line joint bending stiffness. The FE results agreed well with the test ones. According to the FE results, it is indicated that the AAG joint stiffness should be considered in the design of the single-layer reticulated domes.