反复荷载作用下方钢管混凝土柱与钢梁连接节点非线性有限元分析

本文首先选择合适的本构模型作为约束混凝土循环本构模型的骨架曲线,提出了考虑局部屈曲和开裂的钢材循环本构关系;进而建立两类方钢管混凝土柱与钢梁连接节点———缀板焊接连接节点和穿芯螺栓-端板连接节点的空间非线性分析模型,对其在低周反复荷载作用下的滞回性能进行了非线性分析计算。结果表明:由有限元模型所得的单调荷载-位移曲线与试验所得的低周反复荷载作用下的骨架曲线极为相似,但在峰值荷载后差异较大;由有限元模型所得的在低周反复荷载作用下滞回曲线也与在反复荷载作用下试验所得的相一致。有限元模型能准确地预测上述两类节点的弹塑性行为和整体抗震性能,可用于节点滞回性能的非线性参数分析研究。

Nonlinear finite element analysis of the concrete filled square steel tubular column to steel beam connections under low-cycle reversed loading

In this paper,three kinds of constitutive models of confined concrete under monotonic loading have been compared,and a suitable model is selected as the framework curve of the constitutive model under low-cycle reversed loading.The cyclic stress-strain constructive relationship of steel is proposed,which takes into account of the effects of local buckling and cracking of steel.Nonlinear 3D finite element(FE) models of the two kinds of connections,namely sided-plate welding(SPW) connection and stiffened end plate(SEP) connection,under the cyclic loading by using the ANSYS program are established.The nonlinear analysis of the above two kinds of concrete filled square steel tubular column to steel beam connections has been conducted.It is demonstrated that the monotonic load-displacement curves from the FE models agree well with framework curves of the cyclic behavior from the low-cycle reversed loading tests,but there is a great difference after the load-peak value.The hysteresis loops from FE models under low-cycle reversed loading also agree well with those of the cyclic loading tests.The FE models can accurately predict the overall seismic behavior and the inelastic performance of these two kinds of connections,and can be used to conduct the nonlinear parameter analysis of the composite connections.