基于子模型的蜂窝梁孔间腹板受剪屈曲承载力计算方法

发布时间：2018-02-23 00:04

本文关键词： 蜂窝梁孔间腹板剪切屈曲剪切屈曲系数设计计算公式　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：蜂窝梁由H型或I型钢梁在腹板沿一定曲折线进行切割并错位拼接、焊接而成。根据切割方式的不同,可以制作出六边形、八边形、圆形和其他异型孔蜂窝梁。相比原型实腹钢梁,蜂窝梁在不增加用钢量的情况下具有更高的刚度,同时腹板孔洞的存在可以让建筑设备从蜂窝梁中穿过,有效降低建筑层高。由于腹板孔洞的存在,蜂窝梁会发生孔间腹板屈曲等新的破坏形式,本文提出了六边形孔蜂窝梁在弹性阶段和弹塑性阶段的剪切屈曲系数的实用计算公式,简化了蜂窝梁孔间腹板剪切屈曲承载力的计算。本文通过有限元分析方法研究竖向荷载下六边形孔蜂窝梁的孔间腹板屈曲性能。将蜂窝梁上T形腹板作为楔形隔离体对待,将蜂窝梁孔间腹板屈曲问题简化为板件受水平剪力作用失稳的问题。借用薄板剪切屈曲承载力计算公式,按照蜂窝梁孔间腹板的尺寸特点对公式进行修正,得到六边形孔蜂窝梁孔间腹板剪切屈曲承载力计算公式。将楔形隔离体作为有限元子模型代替整体模型进行分析,通过对子模型边界条件的调整使得子模型在受力性能上能够与整体模型吻合。通过对孔间腹板宽度与腹板厚之比e/tw,孔高与腹板厚之比h0/tw,孔洞上方T形腹板高度与腹板厚之比hf/tw,腹板厚tw以及六边形孔洞的边倾角α等五个参数的分析,探究了其对剪切屈曲承载力和剪切屈曲系数的影响。在大量参数分析的前提下,分别拟合出了弹性阶段以及弹塑性阶段的剪切屈曲系数的计算公式,进而得到了六边形孔蜂窝梁竖向孔间腹板屈曲承载力的计算公式。弹性阶段承载力的计算公式与有限元结果吻合较好,由于实验试件大多发生弹塑性屈曲破坏,因此弹性阶段公式计算值相对实验结果较高,引入安全系数后公式计算值精度提高。弹塑性阶段的屈曲承载力计算公式与有限元分析结果和实验结果吻合较好,将弹塑性阶段承载力的计算公式与欧洲规范值对比,揭示了欧洲规范使用"斜压柱"模型计算蜂窝梁孔间腹板屈曲承载力的局限性。
[Abstract]:The beehive beam is made of H-shaped or I-shaped steel beams cut along certain twists and turns on the web and welded. According to the different cutting methods, hexagonal and octagonal shapes can be made. Circular and other special-shaped beehive beams. Beehive beams have higher stiffness without increasing the amount of steel used, compared to prototype full-web steel beams, and web holes exist that allow construction equipment to pass through the beehive beams. Due to the existence of web holes, new failure forms such as web buckling between holes will occur in honeycomb beams. In this paper, a practical formula for calculating shear buckling coefficients of hexagonal honeycomb beams in elastic and elastic-plastic stages is presented. The calculation of shear buckling capacity of web between honeycomb beams is simplified. In this paper, the buckling behavior of interhole web of hexagonal honeycomb beams under vertical load is studied by finite element method. The T-shaped webs on honeycomb beams are treated as wedge-shaped isolators. In this paper, the problem of web buckling between honeycomb beams is simplified as the instability of plates subjected to horizontal shear force. The formula is modified according to the size characteristics of web between honeycomb beams by using the formula of shear buckling capacity of thin plate. A formula for calculating the shear buckling capacity of web between honeycomb beams with hexagonal holes is obtained. The wedge isolator is used as the finite element submodel instead of the integral model to be analyzed. By adjusting the boundary conditions of the sub-model, the sub-model can fit the overall model in terms of mechanical performance. By comparing the ratio of the width of the web between holes to the thickness of the web, the ratio of the height of the hole to the thickness of the web, the ratio of the height of the hole to the thickness of the web, the height of the T-shaped web above the hole and the thickness of the web are compared. The analysis of five parameters, such as the ratio of web thickness to thickness, the thickness of web, tw, and the edge dip angle of hexagonal hole, In this paper, the influence of shear buckling capacity and shear buckling coefficient on shear buckling capacity and shear buckling coefficient is investigated. On the premise of analyzing a large number of parameters, the formulas for calculating shear buckling coefficient in elastic stage and elastic-plastic stage are fitted, respectively. Furthermore, a formula for calculating the buckling capacity of the web between vertical holes of hexagonal honeycomb beams is obtained. The calculation formula for the bearing capacity in the elastic stage is in good agreement with the finite element results, because the elastoplastic buckling failure occurs in most of the experimental specimens. Therefore, the calculated value of the elastic stage formula is higher than that of the experimental one, and the precision of the formula is improved by introducing the safety factor. The calculation formula of the buckling capacity in the elastic-plastic stage is in good agreement with the results of the finite element analysis and the experimental results. By comparing the calculation formula of elastic-plastic stage bearing capacity with the European Code, the limitations of the European Code for calculating the buckling capacity of web between honeycomb beams are revealed by using the "baroclinic column" model.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU391

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