结构延性节点的抗震性能分析与对比研究

发布时间：2018-01-28 03:51

本文关键词： 钢节点延性单元刚度矩阵低周循环时程分析　出处：《西南石油大学》2014年硕士论文　论文类型：学位论文

【摘要】：在美国的北岭和日本的阪神发生罕遇地震之前,钢结构梁柱节点一直被各国专家学者认为是具有良好抗震性能的。地震发生后,多数节点发生了脆性破坏,各国学者开始着手优于一般刚性节点的具有抗震性能的延性节点。在保证“强柱弱梁”的前提下,提出了削弱式节点和加强型节点两种形式。这里结合狗骨式节点和扩翼式节点,对前人提出的扩翼狗骨式节点进行验证,并与前两者进行对比,分析各节点的优劣。通过结构力学的矩阵位移法,对所研究结点的各个力分量进行叠加,根据前人得出的普通节点(Normal Connection)、狗骨式节点(Reduced Beam Section Connection),得出扩翼式节点(Widened Flange Connection)、扩翼狗骨式节点(Flange Reinforced Dog-bone Connection)的梁单元刚度矩阵,得出削弱式节点的剪切刚度系数与抗弯刚度系数受节点刚度变化的影响很大,节点的整体稳定性与平面外稳定性计算不可忽略。采用ABAQUS软件进行有限元模拟,根据以上介绍的几个钢节点类型,分别模拟在静力循环荷载和地震动力荷载作用下节点的受力性能。首先,分别设计了四个独立的梁柱节点,施加低周循环荷载,得出弹性变形和塑性变形阶段的应力云图,并通过软件计算结果绘制出节点的滞回曲线、关键应力路径,对其耗能能力和刚度退化进行对比分析。得到节点的受力云图,进而观察塑性铰的形成与发展趋势,发现了扩翼狗骨式节点在保证足够的极限承载能力下,还可以明显实现塑性铰的外移。然后,对四种节点分别建立六层、九层、十二层单榀框架的有限元模型,进行模态分析,取前十阶振型对应的自振周期进行对比,得出随着层高的增加,节点的变化对框架刚度的影响越显著。最后,采用时程分析法,通过ABAQUS软件加载埃尔森特罗、塔夫特两种地震波,模拟框架在8度罕遇地震作用下的抗震性能,根据有限元结果用excel表格绘制出框架在地震波下的顶点相对位移-时间曲线和基底剪力-时间曲线。最后得出结论：对六层和九层框架,四种节点的曲线差值变化不大；对十二层框架,四种节点的曲线差值变化明显。扩翼狗骨式框架节点刚度与普通刚性框架节点变化不大,能保证层间位移不明显增大并不明显降低节点承载力的同时,有效地降低基底剪力。
[Abstract]:Before the rare earthquakes occurred in the North Ridge of the United States and Hanshin Japan, the Liang Zhu joints of the steel structure were always regarded by experts and scholars all over the world as having good seismic performance. After the earthquake, most of the joints had brittle failure. Scholars from all over the world have begun to do better than the general rigid joints with seismic performance of ductile joints, under the premise of "strong column weak beam" premise. In this paper, two types of weakened and enhanced nodes are proposed. Combining the dog bone node and the expanded wing node, the former proposed expanded dog bone joint is verified and compared with the former two. The advantages and disadvantages of each node are analyzed. Through the matrix displacement method of structural mechanics, each force component of the studied node is superimposed, and the normal connection is obtained according to the previous results. Reduced Beam Section connection. The expanded Flange connection is obtained. The stiffness matrix of beam element of flange Reinforced Dog-bone connection. It is concluded that the shear stiffness coefficient and the bending stiffness coefficient of the weakened joint are greatly affected by the change of the joint stiffness, and the calculation of the overall stability and the out-of-plane stability of the joint cannot be ignored. The finite element simulation is carried out with ABAQUS software. According to the types of steel joints introduced above, the behavior of joints under static cyclic load and seismic dynamic load is simulated respectively. Firstly, four independent Liang Zhu nodes are designed, and the stress cloud diagram of elastic deformation and plastic deformation stage is obtained by applying low cycle cyclic load, and the hysteretic curves of the joints are drawn by software calculation results. The critical stress path, the energy dissipation capacity and stiffness degradation are compared and analyzed. The stress cloud map of the joint is obtained, and then the forming and developing trend of plastic hinge are observed. It is found that the extended dog bone joint can also achieve the external displacement of plastic hinge obviously under the condition of sufficient ultimate bearing capacity. Then, the finite element model of six, nine and 12 layers of single frame is established, and the modal analysis is carried out. The corresponding natural vibration periods of the first ten vibration modes are compared, and the results show that the height of the frame increases with the increase of the height of the layer. The effect of the change of the joints on the stiffness of the frame is more significant. Finally, the seismic behavior of the frame is simulated by using the time history analysis method and the ABAQUS software to load the two kinds of seismic waves of Elsendro and Taft under the action of 8 degrees rare earthquake. According to the results of finite element method, the relative displacement-time curves of the top of the frame under seismic waves and the shear-time curves of the base are plotted by using the excel table. Finally, the conclusion is drawn: for the six-story frame and the nine-story frame. The curve difference of the four nodes has little change. For the 12 story frame, the curve difference of the four kinds of joints is obvious, and the stiffness of the expanded dog bone frame joint is not much different from that of the ordinary rigid frame joint. It can ensure that the interstory displacement is not obviously increased and the bearing capacity of the joints is not obviously reduced, and the base shear force can be effectively reduced at the same time.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391;TU352.11

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