基于累积变形半刚性连接的古建木构件承载力研究

发布时间：2018-06-24 06:35

本文选题：古建筑木结构 + 木构件　；参考：《北京交通大学》2017年硕士论文

【摘要】：木梁和柱构件是古建筑木结构中重要的受力部分,在自然环境的影响下存在着各种各样的累积变形,如木梁和柱的挠曲变形、木柱端部的侧移;累积变形的存在对木构件的受力性能产生不利的影响,甚至威胁着古建筑木结构的安全。本文以古建木构件为研究对象,基于木材正交各向异性和木构件半刚性连接特性进行了累积变形下弹性阶段和塑性阶段的公式推导与数值模拟。主要研究内容如下:1、根据计算简图分别推导了端部半刚性连接下累积变形的木梁在均布荷载和木柱在端部轴向荷载作用下正交各向异性弹性解析解;对于累积变形木柱弹性解的推导,本文采用了等效荷载法;进而根据理论公式分别讨论了累积变形、半刚性对木构件受力性能的影响;2、结合木构件的受力性质,将木材正交各向异性简化为顺纹方向各向同性,推出了木梁、柱承载力公式;根据截面应力-应变关系分别推导了发生三种破坏类型时承载力公式,将荷载-位移曲线简化为双线性,得到了木梁的近似挠度计算方法;推导了端部无侧移半刚性连接理想柱的弹性临界荷载公式,并讨论了端部不同半刚性连接下的计算长度系数;在考虑了柱顶端侧移和跨中挠曲影响下,推导了累积变形柱的承载力公式,并讨论了累积变形对柱承载力的影响;3、为了验证公式推导的正确性,本文基于Ansys建立了多个累积变形下木构件的数值模型,通过施加弹簧单元模拟古建筑木梁柱半刚性的连接特性,在验证模型正确性的前提下,将数值结果和理论公式进行了对比,发现数值结果和理论公式吻合良好。
[Abstract]:Wood beam and column member is an important part of wood structure in ancient architecture. Under the influence of natural environment, there are a variety of accumulated deformation, such as flexural deformation of wood beam and column, lateral displacement of the end of wood column. The existence of accumulated deformation has adverse effects on the mechanical properties of wood members and even threatens the safety of ancient wooden structures. In this paper, the formulas of elastic and plastic stages under cumulative deformation are derived and numerically simulated based on the properties of orthotropic wood and semi-rigid connections of wood members. The main research contents are as follows: 1. According to the calculation diagram, the analytical solutions of orthotropic elasticity of wood beams with cumulative deformation under uniform load and end axial load are derived respectively. In this paper, the equivalent load method is used to deduce the elastic solution of accumulated deformed wood columns, and the influence of cumulative deformation and semi-rigidity on the mechanical properties of wood members is discussed respectively according to the theoretical formulas, and combined with the mechanical properties of wood members. In this paper, the orthotropic anisotropy of wood is simplified to isotropic direction along the grain, and the formula of bearing capacity of wood beams and columns is derived, and according to the stress-strain relation of section, the formulas of bearing capacity of three failure types are derived respectively. The load-displacement curve is simplified as bilinear, and the approximate deflection calculation method of wood beam is obtained, and the elastic critical load formula of the ideal column with no lateral displacement is derived. The calculated length coefficients under different semi-rigid connections at the end of the column are discussed, and the bearing capacity formula of the cumulative deformation column is derived considering the influence of the lateral displacement of the top of the column and the deflection in the middle of the span. The influence of cumulative deformation on the bearing capacity of columns is discussed. In order to verify the correctness of the formula, the numerical models of wood members under cumulative deformation are established based on Ansys. By applying spring element to simulate the Liang Zhu semi-rigid connection of ancient building wood, the numerical results are compared with the theoretical formula on the premise of verifying the correctness of the model. It is found that the numerical results are in good agreement with the theoretical formulas.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU366.2

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