【作者】 孙哲；

【导师】 李振环；

【作者基本信息】 华中科技大学 ， 结构工程， 2007， 硕士

【摘要】 钢结构因其轻质高强、抗震性能好、工业化程度高、施工速度快和投资效益高等综合优势,在国内外应用十分广泛。近年来随着高强度材料的应用、分析模型和技术的日趋精细,使钢结构的重量更轻、跨度更大、刚度更柔、体形日愈复杂。这使得钢结构的稳定性计算的重要性更为突出,并决定了钢结构的整体稳定分析要考虑几何非线性,要能有效地考虑结构的初始缺陷,必要时还要考虑几何非线性和材料非线性相互耦合的双重非线性,以及由上述因素引起的屈曲荷载降低和屈曲性能的改变。但现行的钢结构规范,主要解决的是构件和板件的稳定,常以框架柱的稳定性计算代替框架整体稳定分析(称之为计算长度法)。这种整体稳定分析方法只适用于普通框架结构。用于和假定相近的框架时,近似程度很好,但用于和假定条件相差较多的框架,或者更复杂的空间结构时,误差较大,整体稳定分析缺乏适用性。本文通过分析钢框架结构稳定性问题的特点,在介绍和探讨考虑几何和材料双重非线性的钢框架极限承载力研究的基础上,以某复杂钢框架结构为例,采用ANSYS有限元程序对其进行稳定性计算分析。通过正确的有限元建模,选择合适的计算方案和迭代技术,对该结构在载荷作用下的变形和失稳过程进行了计算和模拟,得到了荷载-位移曲线和极限承载力大小,给出结构在给定荷载下的安全储备或超载能力,为结构设计和营运管理提供依据和保障。根据双非线性稳定性分析计算结果,详细分析了该结构各重要构件的塑性发展过程,并给出结构在设计过程中应该着重考虑的薄弱部位。复杂结构的非线性稳定全过程分析目前在理论和软件应用上都并不是很成熟。ANSYS为少数几个提供了非线性屈曲分析的软件之一。根据计算过程中可能遇到的各种问题以及解决方式,本文对使用ANSYS软件进行复杂钢框架结构的非线性稳定性分析给出一些经验性的建议。更多还原

【Abstract】 Steel constructions are widely used in modern building for their remarkable advantages such as lightweight great intensity quality, well anti-seismic behavior, high industrialization degree, quick construction velocity, etc. Buckling analysis is a vital step in the design of steel constructions. In recent years, because of the application of high intensity materials, and the development of precise modeling and analysis technology, steel constructions develop quickly with more light weight, more large span, and more complex structure shape. These changes make the buckling analysis more important and complicated, so that the geometrical nonlinear and material nonlinear must be considered in the buckling analysis for getting more accurate simulation to reveal the real buckling behavior of steel constructions.However, the present design code of steel structure just solve the buckling problem of structural elements, such as columns and planes, and usually take account of the local buckling analysis of frame columns instead of global stability of the whole steel frames. It is an appropriate method when used in the common regular steel frames, but might bring error when used in the analysis of complicated space steel frame and can not provide meaningful ideas for the practical constructions.In this paper, the buckling characteristics of the steel frame structure are introduced. With deeply study of ultimate bearing load considering both the geometrical nonlinear and material nonlinear, a complex non-regular steel frame structure is analyzed to research its ultimate bearing load and buckling behavior by the common element code ANSYS. By accurately modeling and proper calculation technology, the load displacement curves and ultimate bearing load are obtained, which can show the safety storage and overload capacity, and provide assistance for the structure design and safe usage. Moreover, according to the result of bi-nonlinear analysis results, the plastic zone development of the important components is described, so is the critical place in the structure design.In fact, both of the theory and the code application of the nonlinear buckling analysis are not perfect at present. ANSYS is one of the few codes which can support nonlinear buckling analysis. However it is not an easy task but has many difficulties in the analysis process, which requires much experience and attempt. So some useful advices are offered in the field of nonlinear buckling analysis in ANSYS for the structure designers.更多还原