铝合金网壳箱形-工字形杆件盘式节点受力性能试验研究

Experimental study on mechanical performance of box-I section member TEMCOR joints in aluminum alloy shell structures

为研究铝合金网壳箱形、工字形截面杆件盘式连接节点(又称TEMCOR节点、板式节点)的受力性能,对南京牛首山佛顶宫工程典型铝合金盘式节点足尺试件进行了静力加载试验,采用通用有限元程序ABAQUS对加载过程进行全过程数值模拟。在进行静力加载试验时,铝合金杆件端部采用铰接,在节点盘中心区域设置加载板进行竖向加载。研究结果表明:在节点盘中心竖向荷载作用下试件发生脆性破坏。对向两杆为箱形截面(试件JD1)时,箱形截面杆件下翼缘发生断裂,上下节点盘屈曲,且与断面相邻的螺栓被拉断;对向杆件为工字形截面(试件JD2)时,下节点盘发生块状撕裂,破坏时铝合金型材及螺栓均无屈曲和破坏。在极限荷载作用下,试件JD1杆件腹板及节点盘仍处于弹性工作状态,箱形截面中性轴位于截面中间;试件JD2铝合金型材处于弹性工作状态,工字形截面中性轴位于截面强轴以下1/6腹板高度处,下节点盘在α=60°及α=180°方向应力较大,接近屈服强度。试件JD1的极限荷载和初始刚度均约为试件JD2的1.5倍。根据对称性建立的节点试件数值模型分析所得的局部应力、荷载-位移曲线及弯矩-转角曲线与试验结果吻合较好,可以用于此类节点的数值模拟。

In order to study the mechanical behavior of box-I section member TEMCOR joints used in aluminum alloy shell structures, experiments of two full-scale specimens of TEMCOR joints of different sizes used in Niushou Mountain Buddha Palace project under static load were conducted. Finite element analysis by ABAQUS was used to simulate the experimental process. In the experiment, the ends of the beams were simply supported, and the vertical loads were applied to the center region of the joint. The experimental data and phenomena show that failure mode of the two kinds of specimens is brittle failure. When subjected to ultimate load, failure mode of specimen JD1 whose two opposite members are box-section members is that the bottom flange of one box-section member is fractured, top and bottom plates buckle and bolts near the fracture surface are broken. Failure mode of specimen JD2 whose two opposite members are I-section members under ultimate load is that the bottom plate is fractured while members and bolts are intact. Stress distribution under ultimate load is that the web and plates of JD1 are elastic and satisfies plane cross- section assumption with neutral axis in the middle of the cross-section. Members of JD2 are elastic while neutral axis of I section member is at 1/6 height of the web lower than the major axis of the cross-section. Stress of the bottom plate where α =60° and α = 180° is close to yield strength. The ultimate capacity and initial rotational stiffness of JD1 are both nearly 1.5 times that of JD2. The local stress distribution, load-vertical displacement curves and moment-rotation curves obtained from finite element models agree well with experimental results which can be references to similar joints.