【作者】 郁有升；

【导师】 王燕；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2008， 博士

【摘要】 钢框架梁翼缘削弱型节点（RBS）是将塑性铰外移的一种典型节点形式,在距梁端一定距离将梁的上下翼缘进行削弱,迫使塑性铰的位置离开受力复杂且脆弱的焊缝外移至梁上,达到减少节点脆性破坏可能性、提高节点延性的目的。本文针对梁翼缘圆弧式削弱型节点开展了试验和数值分析两方面的研究工作。研究了圆弧式削弱型节点在循环荷载作用下的节点延性和滞回性能,共进行了6个大比例尺模型的拟静力加载试验,其中5个模型用于研究梁翼缘的削弱深度、削弱长度以及削弱起始点位置对RBS节点的破坏形态、极限荷载、最大塑性转角等特性。作为比较,还进行了一个普通全焊接节点的试验。试验结果表明,RBS节点与普通型梁柱节点相比较,具有良好的塑性变形能力和耗能性能。RBS节点试件的滞回曲线丰满,滞回环面积比较大;而普通型节点试件的滞回曲线显得扁长、不丰满。试验中5个节点的塑性转角都大于0.04rad,延性系数大于4.0,达到了抗弯钢框架连接塑性转角不小于0.03rad,延性系数不小于4.0的要求。分析结果表明:RBS节点比传统节点具有更强的耗能能力,可以在梁翼缘削弱区域形成塑性铰,避免梁根部应力发展导致梁柱连接焊缝出现脆性破坏,有利于实现抗震设计中“强节点弱构件”的思想。采用ANSYS有限元软件对全焊接翼缘削弱型（RBS）节点试件和普通焊接节点试件进行了循环荷载以及静力荷载作用下的有限元分析计算。循环荷载作用下有限元分析的主要内容为:对试验中测试的六个试件建立了计算模型,进行了循环荷载作用下的三维非线性有限元分析,系统分析了梁翼缘削弱参数对翼缘削弱型节点受力性能的影响。讨论了梁翼缘的削弱深度、削弱长度、削弱起始位置不同对试件破坏形态、极限荷载、最大塑性转角、滞回性能等影响,并与试验结果进行了对比分析。静力荷载作用下有限元分析的主要内容为:对17个RBS节点试件和1个普通节点试件进行了静力荷载作用下的三维非线性有限元分析。重点分析讨论了梁翼缘削弱后梁应力分布规律以及翼缘削弱对试件承载力的影响,探讨了梁端塑性铰外移的有效性,讨论了削弱起始位移、削弱长度、削弱深度三参数对塑性铰形成的影响,对设计中计算RBS节点的极限荷载公式中的承载力系数C_pr做了讨论分析,并给出建议值。更多还原

【Abstract】 Reduced beam section （RBS） connection of steel frame is one of the typical forms to move plastic hinge outward from the beam and column interface. By trimming beam flanges, the plastic hinge will form away from the welds that have much fracture proneness due to stress concentration and welding sensitivity, reducing the possibility of brittle fracture of connections and improving the ductility of the structure with RBS connections. In this dissertation, experimental and theoretical research on RBS connections with radius cut has been done.Six specimens under cyclic load were tested to investigate their hysteretic behavior and ductility behavior. Five specimens with different trimming depths, trimming lengths and trimming distances from column surface were conducted to get the effect for failure mode, ultimate load, plastic rotation angles and ductility behavior. In addition, one specimen with full welded connection was tested to compare their cycle behaviors. The test results show that RBS connections have a better plastic deformation and capacity of consuming energy than common connections. Hysteretic curves of RBS connection were well-shaped with large-area hysteretic loops, however, Hysteretic curves of common connection were flat. The plastic rotation angles of the five RBS specimens exceeded 0.04rad and their ductility coefficient exceeded 4.0, meeting the requirement for plastic rotation angles of 0.03rad and ductility coefficient of 4.0. Analysis results show that specimens with RBS connection have better capacity of consuming energy, and they can produce plastic hinge in region of beam trimmed, alleviating the stress state greatly and reducing the possibility of brittle fracture from weld, so that the strong-joint and weak-member design philosophy can be realized.Specimens with RBS connection and common connection under cyclic load and static load were analyzed respectively in the finite element software ANSYS. The main content of the finite element analysis under cyclic load was that the six specimens that had been used in the test were analyzed by 3D non-linear finite element method. Influence of beam flanges reducing parameters on mechanical behaviors of RBS connection was discussed systematically. Influence of trimming depth, trimming length and trimming distance on failure mode, ultimate load, plastic rotation angles and hysteretic behavior was discussed, and the results were contrasted with the test. The main content of finite element analysis under static load was that 17 specimens with RBS connection and 1 specimen with common connection were analyzed in ANSYS with 3D non-linear finite element. Stress distribution in the beam and bearing capacity of the specimens with RBS connection were mainly analyzed, and the effectiveness on the external motion of plastic hinge was discussed. And influence of trimming depth, trimming length and trimming distance on formation of plastic hinge was discussed, moreover, the bearing capacity coefficient C_pr in the equation of RBS connection design was discussed and the suggestion value was proposed.更多还原