门式刚架的稳定分析
发布时间：2019-05-20 02:48
【摘要】：钢结构的门式刚架由于钢材的高强,可做的比较轻质和细柔,这就使得稳定问题显得特别突出。稳定问题属于二阶问题,即需要考虑变形后的平衡,而传统的一阶强度问题仅须考虑变形前的平衡,因此二阶的稳定问题比一阶的强度问题复杂,属于几何非线性。稳定问题的核心是求解杆件或结构的稳定承载力(即临界力)。虽然求解单个杆件临界力并不困难,但要求解整个结构的临界力就不容易了。在现行的《钢结构设计规范》(GB50017-2003)中虽有求解框架计算长度系数的表格(见附录D),但该表格隐含了一些假设,使其只能用于规则刚架(各柱轴力相同),而对于不规则刚架(各柱轴力不同)则不再适用了。另外规范中也没有关于能确定斜梁门式刚架计算长度系数的公式或表格。针对这种现状,本论文从门式刚架(包括斜梁门式钢架)入手,推导了刚架整体稳定的临界方程(超越方程),进而求解,进过几千次的求解之后,得到了大量的数据,制成了刚架柱计算长度系数的诺模图。用这些诺模图可快速的计算出柱子的计算长度系数。本论文最有价值的成果是附录A-C中的诺模图,这些诺模图的正确性和可靠性是经过了有限元计算的检验,且计算精度很高。是快速计算不规则门式刚架柱临界力很好的工具,面对《钢结构设计规范》目前还没有该方面的计算表格,也算是一种补充。在我硕士生阶段,对稳定理论经历了从初期的陌生,到中期的熟悉,再到后期的喜爱,正感到能深入做点研究的时候,剩下的时间已经不多了。另外,对于多杆结构的整体稳定求解,未知量的数目会随着杆件和节点的数量增加而增加,导致要解析获得最终的临界方程的难度增大,比如..如何通过手算来降阶含有众多超越函数的高阶行列式?是我遇到的难题,也限制了解析方法在更复杂的结构上的运用。另一方面,从研究工作中让我也看到:关于不规则结构(各柱轴力不相同)临界力的计算方面,还有很多工作可做,这些结构更符合实际的荷载情况,但又难以在现行的一些规范中找到相关的计算公式或表格。本论文还在参数分析方面做了一些工作,得到了一些刚架柱临界力随各参数变化的趋势。
[Abstract]:Because of the high strength of steel, the portal frame of steel structure can be made light and soft, which makes the stability problem particularly prominent. The stability problem belongs to the second-order problem, that is, the equilibrium after deformation needs to be considered, while the traditional first-order strength problem only needs to consider the balance before deformation, so the second-order stability problem is more complex than the first-order strength problem and belongs to geometric nonlinear. The core of the stability problem is to solve the stable bearing capacity (that is, critical force) of the member or structure. Although it is not difficult to solve the critical force of a single member, it is not easy to solve the critical force of the whole structure. Although there is a table for calculating the length coefficient of the frame in the current Code for the Design of Steel structures (GB50017-2003) (see Appendix D), the table implies some assumptions that it can only be used in regular rigid frames (the axial forces of each column are the same). However, it is no longer applicable to irregular rigid frames (different axial forces of each column). In addition, there is no formula or table for determining the length coefficient of oblique beam portal frame in the code. In view of this situation, this paper starts with the portal rigid frame (including oblique beam portal steel frame), deduces the critical equation of the overall stability of the rigid frame (transcendental equation), and then solves it. After thousands of times of solution, a large number of data are obtained. A normograph for calculating the length coefficient of rigid frame columns is made. The length coefficient of the column can be calculated quickly by using these normograms. The most valuable achievement of this paper is the normogram in Appendix A / C. the correctness and reliability of these normograms have been tested by finite element calculation, and the calculation accuracy is very high. It is a good tool for fast calculation of critical force of irregular portal rigid frame columns. At present, there is no calculation table in the face of "Code for Design of Steel structures", which is also a supplement. In my master's degree stage, the stability theory experienced from the initial unfamiliar, to the middle of the familiar, and then to the later love, is feeling able to do some in-depth research, there is not much time left. In addition, for the overall stability solution of multi-bar structure, the number of unknown quantities will increase with the increase of the number of members and nodes, which makes it more difficult to analyze and obtain the final critical equation, for example. How to reduce the order of higher order determinant with many transcendental functions by hand calculation? It is a difficult problem that I encounter, and it also limits the use of analytical methods in more complex structures. On the other hand, from the research work, I can also see that there is still a lot of work to be done on the calculation of critical force of irregular structures (the axial forces of each column are different), and these structures are more in line with the actual load situation. However, it is difficult to find the relevant formulas or tables in some existing specifications. In this paper, some work has also been done in parameter analysis, and some trends of critical force of rigid frame column with each parameter have been obtained.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU392.5
本文编号：2481282
[Abstract]:Because of the high strength of steel, the portal frame of steel structure can be made light and soft, which makes the stability problem particularly prominent. The stability problem belongs to the second-order problem, that is, the equilibrium after deformation needs to be considered, while the traditional first-order strength problem only needs to consider the balance before deformation, so the second-order stability problem is more complex than the first-order strength problem and belongs to geometric nonlinear. The core of the stability problem is to solve the stable bearing capacity (that is, critical force) of the member or structure. Although it is not difficult to solve the critical force of a single member, it is not easy to solve the critical force of the whole structure. Although there is a table for calculating the length coefficient of the frame in the current Code for the Design of Steel structures (GB50017-2003) (see Appendix D), the table implies some assumptions that it can only be used in regular rigid frames (the axial forces of each column are the same). However, it is no longer applicable to irregular rigid frames (different axial forces of each column). In addition, there is no formula or table for determining the length coefficient of oblique beam portal frame in the code. In view of this situation, this paper starts with the portal rigid frame (including oblique beam portal steel frame), deduces the critical equation of the overall stability of the rigid frame (transcendental equation), and then solves it. After thousands of times of solution, a large number of data are obtained. A normograph for calculating the length coefficient of rigid frame columns is made. The length coefficient of the column can be calculated quickly by using these normograms. The most valuable achievement of this paper is the normogram in Appendix A / C. the correctness and reliability of these normograms have been tested by finite element calculation, and the calculation accuracy is very high. It is a good tool for fast calculation of critical force of irregular portal rigid frame columns. At present, there is no calculation table in the face of "Code for Design of Steel structures", which is also a supplement. In my master's degree stage, the stability theory experienced from the initial unfamiliar, to the middle of the familiar, and then to the later love, is feeling able to do some in-depth research, there is not much time left. In addition, for the overall stability solution of multi-bar structure, the number of unknown quantities will increase with the increase of the number of members and nodes, which makes it more difficult to analyze and obtain the final critical equation, for example. How to reduce the order of higher order determinant with many transcendental functions by hand calculation? It is a difficult problem that I encounter, and it also limits the use of analytical methods in more complex structures. On the other hand, from the research work, I can also see that there is still a lot of work to be done on the calculation of critical force of irregular structures (the axial forces of each column are different), and these structures are more in line with the actual load situation. However, it is difficult to find the relevant formulas or tables in some existing specifications. In this paper, some work has also been done in parameter analysis, and some trends of critical force of rigid frame column with each parameter have been obtained.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU392.5
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