梁柱斜交外伸端板连接节点的力学性能及改进措施

Mechanical behavior and improvement measures of inclined extended end-plate moment connections

为研究角度对梁柱斜交外伸端板连接节点力学性能的影响,本文设计了6个具有不同倾角的外伸端板节点,采用ABAQUS程序建立其非线性有限元模型,系统分析了此类节点在循环荷载作用下的滞回性能,并根据其受力特征,评估了三种用于减小应力集中改进措施的有效性。分析结果表明:锐角侧钢梁翼缘及腹板区域峰值应力水平较高,存在应力集中现象。钢梁倾角在0~45°范围内,随着梁柱倾斜角度的增加,梁柱斜交外伸端板连接节点的滞回曲线趋于饱满,节点抗弯承载力呈增大趋势。除正交节点外,随钢梁倾角增加,节点初始转动刚度略呈增大趋势。通过增设端板加劲肋、设置狗骨式截面均可降低钢梁端部应力水平,减缓应力集中,增强钢梁与端板之间对接焊缝的可靠性。通过在锐角侧钢梁腹板切割斜槽或弧形槽也可降低该区域的应力集中,但导致节点滞回性能劣化,抗弯承载力及初始转动刚度降低。

In order to investigate the angle influence on the mechanical behaviors of sloped beam-to-column extended end-plate connections, a total of six sloped extended end-plate connection specimens with different angles are designed. Its nonlinear finite element model is established using ABAQUS program, and the hysteretic behavior of this kind of beam-to-column connections subjected to the cyclic load is systematically analyzed. According to the mechanical characteristic, the effectiveness of three improvement measures for reducing stress concentration is evaluated. The analysis results show that the peak stress in the region of flange and web of the acute-angle side of steel beam is very higher, and the stress concentration phenomenon is monitored. When the inclined angle is in the range from 0 to 45°, the hysteresis curve becomes more and more full, and the flexural moment capacity of connection exhibits the increasing tendency with the increase of the inclined angle. Except for orthogonal sloped beam-to-column extended end-plate connection, the initial rotation stiffness of connection slightly increases with the increase of inclined angle of steel beam. By adding end-plate stiffening ribs and setting RBS effectively decreases the stress level at the end of steel beam, the stress concentration is reduced, and the reliability of butt weld between steel beam and end-plate is enhanced. Cutting oblique grooves or arc-shaped grooves in the web of the acute-angle side in steel beam can also reduce the stress concentration in this region, but it leads to the deterioration of the hysteretic behavior of connection and the reduction of flexural moment capacity and initial rotation stiffness.