钢框架梁翼缘扩翼型节点受力性能研究

Study on the mechanical properties of widened beam flange connections of steel frame

针对钢框架梁翼缘扩翼型节点试件进行了非线性有限元分析,研究了梁端扩翼形式以及扩翼参数对节点应力、塑性区分布、塑性发展规律以及极限承载力的影响.分析了梁柱对接焊缝处及梁截面改变处的应力分布状况.作为比较,还进行了1个传统型梁柱全焊接刚性连接节点的有限元分析,研究结果表明,圆弧扩翼型节点和侧板扩翼型节点通过将梁翼缘进行适当的扩大后,均能有效的将塑性铰移出焊缝热影响区,避免梁柱连接焊缝附近的脆性破坏,并且比传统普通节点具有更高的极限承载力,是较为理想的延性节点.当采用相同的扩翼参数,圆弧型节点的延性性能要好于加侧板节点,另外对于侧板扩翼式节点,由于扩翼段的末端截面变化突出,易产生局部应力集中现象,建议工程设计中宜采用圆弧扩翼型节点.

Based on the non-linear finite element analysis of the widened beam flange connections, the stress distribution, plastic zone distribution, plasticity development regulation and ultimate bearing capacity of connections are discussed considering the different widened types and parameters. The Von Mises stress distributions of the welding seam at the end of beam and in the variable cross-section are analyzed. In addition, one traditional specimen with full welded connection was studied in comparison. The analytical results show that the plastic hinge of beams can be moved away from welded connection area by appropriately strengthening beam flanges, and the brittle break near the welding seam can be avoided in both arc widened beam flange connections and welded side-plate connections. Meanwhile the widened beam flange connection can apparently improve the bearing capacity in comparison with the normal connection, so they are ideal ductile connections. When using the same widened parameters, the arc widened beam flange connections have better ductility than welded side-plate connections. At the same time, with the welded side-plate connection, the severe stress concentrating is induced because of sharp section change at the end of widened flange sector. As a result, it is suggested that the arc widened beam flange connections should be adopted preferentially in the practical designs.