钢框架梁翼缘削弱型节点循环荷载作用下的有限元分析及试验研究

FINITE ELEMENT ANALYSIS AND EXPERIMENTAL STUDY ON THE BEHAVIOR OF REDUCED BEAM SECTION CONNECTIONS OF STEEL FRAME UNDER CYCLIC LOADING

基于钢框架翼缘削弱型节点低周往复荷载试验的5个试件和1个普通节点的试件,在合理选择有限单元类型基础上,采用通用有限元软件ANSYS对节点进行了循环荷载作用下的受力性能有限元分析,研究了翼缘削弱型节点的破坏形态、极限荷载、最大塑性转角、延性性能、耗能性能。有限元计算得到的荷载-位移滞回曲线及局部破坏形态与试验结果符合较好。研究结果表明:对梁翼缘进行适当削弱后形成的骨型节点在梁翼缘削弱区域可以形成一个扩大的塑性铰区,耗散大部分能量,避免梁根部应力发展导致梁柱连接焊缝过早出现脆性破坏,并且比传统节点具有更强的耗能能力,是一种较为理想的延性节点。研究结果还表明,梁柱间对接焊缝具有良好质量才能充分发挥翼缘削弱型节点的耗能性能。

Based on the experiments of five connections with reduced beam sections （RBS） and one ordinary connection under a cyclic loading, 3-D nonlinear finite element models were used to analyze the mechanical properties of these two types of connections using ANSYS. Based on appropriate fmite element types, fmite element analyses were conducted under the cyclic loading. The failure mode, ultimate load, plastic rotation angles, ductility and ability of energy dissipation of the connections with different reduced parameters were investigated. The hysteretic curves and local failure modes by finite element analyses show good agreement with those of the experiments. Analytical results indicate that an expanded plastic hinge could come into being and spread in reduced region of the beam to avoid premature brittle fracture near the butt weld of high stress. Reduced beam section connections have better ability of energy dissipation than ordinary connections, thusly RBS connection is an ideal ductility connection. Research also shows that only good welding quality can make full use of the ability of energy dissipation of RBS connections.