【作者】 刘娟；

【导师】 武振宇；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2006， 硕士

【摘要】 我国钢结构设计规范中没有关于钢管桁架杆件计算长度系数的规定,工程中大多把采用直接焊接节点的结构作为铰接体系来看待。直接焊接搭接方管节点是空间桁架中一种常见的节点形式。研究采用搭接节点的桁架支杆稳定性是必要的。本文利用ANSYS非线性有限元分析方法,对K型搭接节点约束下桁架受压支杆端部节点转动刚度及杆件计算长度系数进行了大规模参数分析。首先,本文将桁架中节点对支杆提供的转动约束简化为半刚性转动弹簧铰支座,在理论上推导了K型搭接节点转动刚度计算公式,并结合欧拉方程,计算出了受节点转动刚度和杆件惯性矩等参数影响的桁架中受压支杆计算长度系数μ。在参数分析中,本文通过近300个节点算例,全面考察了模型主要几何参数对节点转动刚度和受压支杆平面内计算长度系数的影响规律,主要包括:支弦杆宽度比β、搭接率ov、弦杆宽厚比γ、支弦杆厚度比τ、支弦杆夹角θ、整体尺寸系数C及受压支杆的长细比λ。同时,本文也将参数分析得出的结论与采用间隙节点时各参数对节点转动刚度和受压支杆计算长度系数的影响趋势进行比较,总结出采用两种不同节点形式时节点转动刚度和受压支杆计算长度系数随参数变化的异同。更多还原

【Abstract】 The effective length factor of steel tubular truss in the design code of steel structure in china is not specified. The brace of the truss which use directly welded SHS joints is supposed to be pinned in designs. Overlap SHS joints are one of the common joint configurations used in the space truss. So the research on stability of brace restrained by overlap joints in truss is necessary. In this paper, an extensive parametric research on the rotational stiffness and the effective length factor of compression brace of the truss restrained by overlap K joint is carried out by an ANSYS nonlinear finite element analysis.Firstly, the restriction of brace from joint is simplified as semi-rigid restriction against rotation so that the rotation stiffness of overlap K joints can be obtained in theory. Then the relationship between effective length factor and rational stiffness and other parameters such as rotational inertia is found by stability formula and Euler formula.A parameter analysis, including about 300 joints cases, is carried out to investigate the variation of rotational stiffness and effective length with the geometric parameters varying slenderness ratioλ, brace to chord ratioβ, ratio of brace thickness to chord’sτ, ratio of chord width to thicknessγ, angle of brace to chordθ, overlap ratio ov and factor of whole size C .At the same time, the variation of rotational stiffness and effective length with parameters varying when brace is restrained by gap K joints is compared with overlap K joints. The similarities and differences of the two kinds of joints are obtained in this paper.更多还原