【作者】 李育楷；

【导师】 王全凤；

【作者基本信息】 华侨大学 ， 结构工程， 2002， 硕士

【摘要】 本文采用工程实践常用的荷载分解法对矩形截面薄壁杆件的畸变进行分析，研究横隔板间距对畸变效应的影响。 首先，以单轴对称矩形截面薄壁杆件为研究对象，假设其在反对称荷载作用下翘曲位移和切向位移的分布函数，考虑剪切变形的影响，利用最小势能原理建立单位均布畸变荷载作用下的畸变角微分方程。采用微分方程的一般解法对该畸变角微分方程进行求解，并推导求解的初参数格式。随之，通过实例，将本文理论与传统不考虑剪切变形的畸变分析理论及州SYS有限元软件的分析结果作比较，验证了本文理论的正确性，结果还表明考虑剪切变形的影响大大提高了考虑畸变效应的计算精度。 在初参数格式的基础上，本文又推导出考虑剪切变形的畸变分析的刚度矩阵及等效节点载荷列阵，获得便于实际应用的畸变分析刚度法。 最后，深入地研究了横隔板间距对薄壁杆件畸变的的影响。在均布和集中两种反对称荷载情况下，按两端固定、两端简支和悬臂三种不同的支承情况，采用刚度法对同一矩形截面薄壁杆件的畸变和刚性扭转分别进行分析。通过改变横隔板设置的数量，考察在不同横隔板密度下薄壁箱梁的畸变效应，从而得到横隔板设置密度对畸变效应的影响曲线，并与刚性扭转效应作了比较。通过研究得到初步结论：设置一定数量的横隔板可以大幅度地减小薄壁杆件的畸变效应；另一方面，尽管横隔板设置到比较大的密度(横隔板间距与截面最大尺寸之比为1.25)，与刚性扭转效应相比，畸变效应仍不能忽略。因此建议，对薄壁杆件作约束扭转分析时一定要考虑截面畸变的影响。更多还原

【Abstract】 In this paper, the distortion of thin-walled bar with rectangle cross section is examined individually and the effect of diaphragm density on distortion is analyzed.Firstly, with uniaxial symmetrical rectangle cross section, the warping displacement function and tangential displacement function under anti-symmetrical load are supposed. Then taking shear deformation into account and with potential principle, the governing differential equation for distortion angle subjected to uniformly distributed distortion load is established. The differential equation is solved and the format of initial parameters is deduced. With a case, the theory proposed in this paper is compared with the traditional distortion theory which doesn’t take shear deformation into account and ANSYS finite element software to verify the accuracy of the proposed method. It is drawn that taking shear deformation into account results in a fairly higher accuracy.Based on the initial parameters format of the distortion theory in this paper, the element stiffness matrix and the corresponding equivalent nodal force vector subjected to uniformly distributed load is developed.At last, with the stiffness method, the effect of diaphragm density on restraining the distortion of thin-walled bar is analyzed. With different load cases of uniformly load and concentrated load and different boundary conditions of two fixed ends and two simply supported ends and cantilever, the distortion and torsion of the same rectangle thin-walled girder is examined. By changing the amount of the diaphragm, the distortion effect under different density of diaphragm is investigated. The diagram of distortion effect to diaphragm density is drawn and the distortion effect is compared with the effect of rigid torsion. It is concluded that a certain amount of diaphragm will reduce the distortion effect greatly, but on the other hand, even with a fairly great density of diaphragm, such as the ratio of diaphragm span to the greatest dimension of the cross section is as small as 1.25, the distortion effect can’t be neglected compared with the effect of rigid torsion. As a result, it is suggested that distortion should be taken into account to calculate the thin-walled bar with restrained torsion.更多还原