压弯构件非线性分析

发布时间：2018-06-16 15:40

本文选题：压弯构件 + 非线性　；参考：《昆明理工大学》2014年硕士论文

【摘要】：在工程实际中,钢结构的稳定性问题一直是很突出的一个问题,很多钢结构工程因为没有处理好稳定性问题而致使工程破坏,造成重大的经济损失和人员伤亡。钢结构构件主要由杆件(拉杆、压杆)组成。拉杆的承载力主要与材料的抗拉强度有关,而单纯承受轴心压力的杆件很少,大多是由于压力偏心、横向荷载、材料缺陷和几何缺陷等造成压弯作用,形成压弯构件,这就对杆件的稳定性产生很大的影响。因此压杆的承载能力极限值不仅与材料强度有关,更与杆件的稳定性能有关。本文主要对单向压弯构件进行非线性分析,研究的失稳状态为第二类失稳(极值点失稳)。本文考虑了截面的材料非线性,即不但考虑材料的弹性变形阶段,也考虑了截面的塑性变形阶段,这也更加符合客观实际情况。本文从截面到杆件分两个层次进行逐步深入,最终得到压弯构件的荷载-挠度的相关关系及塑性荷载极限值。截面层次非线性分析即研究截面轴力-弯矩-曲率(n-m-φ)的相关关系。本文采用三种有限元数值迭代法(割线刚度矩阵迭代法、切线刚度矩阵迭代法和常刚度矩阵迭代法)对矩形截面和工字形截面进行了分析,并采用matlab软件编程进行计算,得到了大量有价值的数据,并绘制成直观的曲线图。杆件层次非线性分析即研究长细比-偏心距-压力-挠度(λ-e-n-v)的相关关系。本文采用共轭梁法对压弯构件进行分析,采用matlab软件编程进行计算。首先分析了仅考虑弹性时的杆件荷载位移相关关系；然后,分析了考虑弹塑性时的杆件荷载位移相关关系；最后,在弹塑性分析的基础上得到了压弯构件的塑性极限值与长细比值的相关关系。且将以上提到的研究成果均以曲线图的形式进行了展示。通过查看图中曲线,我们可以很方便的得到压弯杆件的塑性极限荷载值。在验证本文研究方法和结论的方法选择上,本文是分两部分进行的：截面层次采用与陈惠发教授的解析法分析结果进行对比验证,吻合度很高；杆件层次采用Ansvs软件进行建模分析,本文分析结果与其得到的结果非常吻合,也间接证明了截面层次分析方法及结果的正确性。
[Abstract]:In engineering practice, the stability of steel structure has been a very prominent problem, many steel structure engineering because of failure to deal with the stability of the engineering damage, resulting in significant economic losses and casualties. Steel structure members are mainly composed of members (pull rod, compression bar). The bearing capacity of the strut is mainly related to the tensile strength of the material, but the members simply bear the axial pressure are few, mostly because of the pressure eccentricity, the transverse load, the material defect and the geometric defect and so on, resulting in the compression and bending member. This will have a great impact on the stability of the members. Therefore, the limit value of bearing capacity is not only related to the strength of material, but also to the stability of the member. In this paper, nonlinear analysis of unidirectional bending members is carried out. The studied instability state is the second kind of instability (extremum point instability). In this paper, the material nonlinearity of the section is considered, that is, not only the elastic deformation stage of the material, but also the plastic deformation stage of the section is considered, which is more in line with the objective reality. In this paper, the relationship of load-deflection and the limit value of plastic load are obtained. The hierarchical nonlinear analysis of the cross section is to study the correlation between axial force, moment and curvature of the section (n-m-蠁). In this paper, three finite element numerical iteration methods (Secant stiffness matrix iteration, tangent stiffness matrix iteration and constant stiffness matrix iteration) are used to analyze the rectangular section and the I-shaped section. A large amount of valuable data is obtained and drawn into an intuitive graph. The hierarchical nonlinear analysis of members is to study the correlation between the slenderness ratio, eccentricity, pressure and deflection (位 -e-n-v). In this paper, the conjugate beam method is used to analyze the bending members and the matlab software is used to calculate them. Firstly, the relationship between load and displacement of members considering elasticity is analyzed. Then, the relationship between load and displacement of members considering elastic-plastic is analyzed. Based on the elastic-plastic analysis, the relationship between the plastic limit value and the slenderness ratio is obtained. And the above mentioned research results are shown in the form of graphs. By looking at the curve in the diagram, we can easily get the plastic limit load value of the bending member. This paper is divided into two parts in the selection of methods to verify the research methods and conclusions of this paper: the cross-section level is compared with the analytical analysis results of Professor Chen Huifa, and the degree of agreement is very high; The Ansvs software is used to model and analyze the member levels. The results of this paper are in good agreement with the results obtained. It also indirectly proves the correctness of the section hierarchy analysis method and the results.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391

【参考文献】