采用楔形构件框架的塑性分析

W. S. King　 C. J. Chen　 L. Duan　 W. F. Chen　

摘　要：对一些平面内楔形截面构件进行二阶简单塑性铰法分析,并利用有限元法及重叠原理推导Ⅰ形钢楔形截面构件的刚度矩阵.为预测构件内部可能形成塑性铰的位置,以一个同时受弯矩及轴力作用的梁柱单元,仿真各种不同边界条件的楔形截面构件.若预测构件内会形成塑性铰的位置则要增设一个节点,将一个构件分割为两个单元,以获得最合理的荷载-挠度曲线.楔形截面构件的刚度矩阵应特别注意方向性的问题.若没有考虑到任一构件中可能形成塑性铰的位置,就不能准确地预测梁柱真实的极限承载能力.若仅用一个单元代表一个楔形截面构件就会高估极限承载能力.该方法可合理地应用于具有楔形截面构件框架的塑性分析.
关键词：楔形构件;梁柱单元;塑性铰;结构工程;钢结构
分类号：TU313.2　文献标识码：A
文章编号：1673-2049(2006)02-0009-11

Plastic Analysis of Frames with Tapered Members

W. S. King（Department of Construction Engineering, Chaoyang University of Technology, Wufeng 00886, Taiwan, China）　 C. J. Chen（Department of Construction Engineering, Chaoyang University of Technology, Wufeng 00886, Taiwan, China）　 L. Duan（Department of Traffic Engineering, University of California, Sacramento CA95816, California, USA）　 W. F. Chen（School of Engineering, University of Hawaii, Honolulu HI96822, Hawaii, USA）　

Abstract：Several in-plane tapered members were analyzed by the simple plastic hinge method.The stiffness matrix of an I-section tapered element was derived by the finite element method with the use of superposition principle. In order to predict the locations of plastic hinges formation in members, an element subjected to bending moments and an axial load was modeled to simulate these tapered members with different boundary conditions. An additional nodal point was set after the formation of a plastic hinge was detected within the element. The most reasonable load and deflection curve could be obtained by using the two elements for each member. One should pay attention to the problem of direction in the stiffness matrix of a tapered element. The actual limit load of a beam-column could not be predicted correctly if the possible formation of a plastic hinge in a member was not considered. The limit load would be overestimated if only one element was used for a tapered member. The results show that the proposed method can be reasonably applied to the plastic analysis of frames with tapered members.
Keywords：tapered member; beam-column element; plastic hinge; structural engineering; steel