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运用有限元方法研究了火灾下六边形孔蜂窝梁在竖向剪力作用下孔间腹板弹性屈曲问题。取孔间腹板的上半部作为隔离体,将蜂窝梁的孔间腹板等效为受水平剪力的楔形悬臂板。根据薄板受剪屈曲理论计算公式,通过屈曲系数k计算孔间腹板受剪屈曲承载力。运用有限元分析获得蜂窝梁竖向剪切屈曲承载力,通过反分析计算屈曲系数k。结果表明:k随着孔间腹板宽厚比和孔洞上方腹板高厚比的增大而非线性减小;随着孔间腹板高厚比的增大而线性增大;随着腹板厚度的增大而线性减小;随火灾升温基本保持不变。在参数分析的基础上,提出了火灾下六边形孔蜂窝梁受剪屈曲系数k的计算公式,简化了蜂窝梁孔间腹板屈曲承载力的设计过程。
The elastic buckling of webs between holes under vertical shearing of hexagonal hole honeycomb beams under fire was studied by means of finite element method. Taking the upper half of the inter-hole web as a spacer, the inter-hole web of the honeycomb girder is equivalent to a wedge-shaped cantilever plate subject to horizontal shear. According to the theoretical formula of shear buckling and buckling of sheet metal, the flexural buckling capacity of webs between holes is calculated by the buckling coefficient k. The vertical shear buckling capacity of honeycomb beam was obtained by finite element analysis, and the buckling coefficient k was calculated by back analysis. The results show that k decreases non-linearly with the increase of ratio of web width to thickness and the ratio of height to thickness of web above the web, increases linearly with the increase of ratio of web height to web thickness, The thickness increases linearly with the decrease; with the fire the basic temperature remains unchanged. Based on the parametric analysis, the formula for calculating buckling coefficient k of hexagonally-shaped honeycomb beam under fire is proposed, which simplifies the design of buckling bearing capacity of honeycomb beam webs.