铝合金网壳结构中新型铸铝节点受力性能试验研究

为研究某植物园铝合金网壳结构中新型铸铝节点的受力性能，进行了3个足尺节点试件的加载试验，考察了3种典型受力情况下铸铝节点的受力性能和破坏机理。试验结果表明，该铸铝节点平面外的抗弯刚度较大，但平面内的刚度较小，且属于半刚性连接节点；螺栓孔处截面是节点的薄弱部位；铸铝节点本身的破坏形式为脆性断裂破坏，延性较差，节点破坏前无明显征兆。同时，还对该铸铝节点在上述3种荷载作用下的受力性能进行有限元分析，并与试验结果进行对比。结果表明，有限元与实测结果吻合较好，验证了有限元模型的准确性和可靠性；同时，有限元结果给出了节点在荷载作用下的应力整体分布状况及随加载过程的变化趋势。基于试验和有限元分析结果，建议在铸铝节点设计中考虑采用合适的安全系数，避免突然破坏。

Experimental study on mechanical performance of novel cast aluminum joints in aluminum reticulated shell structures

To study the mechanical performance of novel cast aluminum joints used in an aluminum reticulated shell structure,three full scale tests on cast aluminum joints under three typical loading conditions respectively were carried out.The failure mechanism were investigated.The test results show that the out-of-plane flexural rigidity of the cast aluminum joint is high while its in-plane flexural rigidity is low,which indicates semirigid.The cross sections at bolt holes are the weakest part.The failure mode of cast aluminum joints is brittle fracture without obvious signs before failure.Meanwhile,the finite element analysis(FEA) of the mechanical behavior of cast aluminum joints was conducted.By comparing the results of experiments and FEA,it is shown that FEA results agree well with the experimental ones which verify the accuracy and reliability of the finite element model.The cast aluminum joint stress distribution and its change trend over the loading history are also given by FEA results.Based on the research,it is suggested that appropriate safety factors should be adopted in the cast aluminum joints design in order to avoid the sudden failure.