【作者】 周丽；

【导师】 舒兴平；

【作者基本信息】 湖南大学 ， 结构工程， 2010， 硕士

【摘要】 圆孔蜂窝拱形曲梁有着自重轻、承载力高、经济美观等特点,近年来在实际工程中应用越来越广泛,然而作为一种新型构件,其受力性能较一般构件的受力性能更为复杂。其稳定问题包括平面内的弯曲屈曲和平面外的弯扭屈曲问题,但弯扭屈曲的临界荷载往往低于弯曲屈曲的临界荷载,若不能提供足够的侧向支撑,往往会先发生弯扭屈曲。因此本文的研究重点为圆孔蜂窝拱形曲梁的弹性弯扭屈曲。本文主要依靠的分析手段是运用大型有限元分析软件ANSYS进行有限元分析。由于截面特性以及开孔率对梁的弯扭屈曲影响已经研究比较透彻,本文主要考虑参数为曲率,以弧长一定,不同圆心角来实现曲率的变化。本文先对已有的在均布径向荷载下两端铰接实腹拱形曲梁的弯扭屈曲临界轴力计算公式和在两端大小相等方向相反的弯矩作用下简支实腹拱形曲梁的弯扭屈曲临界弯矩计算公式分别和圆孔蜂窝直梁腹板等效刚度公式进行组合,但由于腹板等效刚度未考虑曲率的影响,因此通过有限元分析,分析了曲率对弯扭屈曲的影响,将有限元结果与组合公式计算值进行比较,并将两者的比值进行回归分析,拟合出修正系数的计算公式,对组合公式加以修正,从而得出以上两种特殊荷载下的圆孔蜂窝拱形曲梁弯扭屈曲临界内力的计算公式。圆孔蜂窝拱形曲梁的内力情况与压弯构件的受力情况相似,本文对其发生弯扭屈曲时的最大轴力和最大弯矩分别与已经给出两种特殊荷载下得出的弯扭屈曲临界轴力和临界弯矩的比值进行压弯相关分析。由于一般荷载下曲梁的平衡微分方程没有解析解,本文根据压弯相关分析的结果进行回归分析,得出圆孔蜂窝拱形曲梁在一般荷载下弯扭屈曲的内力判定公式。更多还原

【Abstract】 The circular hole castellated vaulted curved beams have the advantages of light weight, high bearing capacity, economy, beauty and so on, so they are have been used in more and more practical engineering in resent years. However, as a kind of new-type members, the mechanical behavior of the circular hole castellated vaulted curved beams is more complicated than the common members. The stability problem includes flexural buckling and flexural-torsional buckling, but the critical load about the flexural-torsional buckling is usually lower than that about flexural buckling, so if there is not enough lateral bracing, the flexural-torsional buckling will occur first. Therefore, the research emphases of this paper is elastic flexural-torsional buckling of the circular hole castellated vaulted curved beams.The main analysis method in this paper is the finite element analysis by ANSYS. For the effects of the sectional characteristic and the open porosity to the flexural-torsional buckling have been researched deeply, the main considered parameter in this paper is curvature, and it is realized by fixing the arc length and changing the central angle.Firstly, this paper combines the formula of the critical axial force about the flexural-torsional buckling occurred in the solid-web vaulted curved beams under the action of the uniform radial load and the formula of the critical moment about the same beams under the action of the same end bending moment with the web equivalent stiffness formula in circular hole castellated straight beams separately. For the web equivalent stiffness formula didn’t considered the effect of the curvature, this paper analyzed the effect of the curvature to the flexural-torsional buckling by finite element analysis, compared the finite element results with the result of the combinatorial formula, made regression analyze on the ratio and fitted the formula of the correction factor to the combined formula. Finally, the formula of the critical internal force under the action of the two special loads of the circular hole castellated vaulted curved beams.The internal force of the circular hole castellated vaulted curved beams is similar to that of the compression-bending member, and therefore, this paper made compression-bending correlation analyze on the ratio of the maximum axial force with the critical axial force under the action of the uniform radial load and the maximum moment with the critical moment under the action of the same end bending moment. Because there isn’t analytical solution about flexural-torsional buckling of the curved beams under the action of the common load, this paper summarized the internal force judgement formula about the flexural-torsional buckling based on the result of the compression-bending regression analyze.更多还原