蜂窝梁弯扭屈曲分析及整体稳定性的计算方法

蜂窝梁是在工字钢或H型钢腹板上按一定的线形进行切割后变换位置重新焊接组合形成的新型钢梁,具有节省材料、便于铺设管道、平面内刚度增大、承载能力高等优点.由于蜂窝梁腹板开孔,与相同截面的实腹梁相比抗侧刚度被削弱,整体稳定性降低.文中以实腹梁临界弯矩计算公式为基础,考虑蜂窝梁的抗侧刚度、翘曲刚度和扭转刚度,给出蜂窝梁弯扭屈曲临界弯矩计算公式,采用ANSYS对纯弯状态下的蜂窝梁进行了弯扭屈曲分析,以蜂窝梁的孔高比和距高比为变量,给出了不同情况下蜂窝梁弯扭屈曲临界弯矩值,并与当量实腹梁临界弯矩公式计算结果进行对比,得出蜂窝梁临界弯矩与当量实腹梁临界弯矩之差随孔高比和距高比之间的变化关系,对蜂窝梁整体稳定性计算公式进行修正,最后提出了蜂窝梁整体稳定性的实用计算方法.

Research on Flexural-Torsional Buckling and Overall Stability Calculation Method for Castellated Beams

Castellated beam is a new type steel beam, which is formed by cutting H-shaped section or I- shaped section steels in a zigzag pattern along its web and then the two halves were rejoined through welding. It is characterized by its lightness, high load-carrying capacity and its convenience for setting pipelines through its web. Compared with the solid web girder, the lateral stiffness and overall stability is weakened because of the web opening of Castellated Beams. Based on the formula for flexural-torsion buckling critical moment of solid web girder, the flexural-torsion buckling critical moment computing formula of Castellated Beams is presented considering the lateral stiffness, warpage stiffness and torsional stiffness. Finite element analyses of Castellated Beams under pure bending are carried out with ANSYS software. The flexural-torsion buckling critical moments under different diameter-depth ratio and space-depth ratio of the web are received and compared to the equivalent solid web beam calculation results. Through the comparison with the results obtained from numerical analysis and calcula- tion results, the error of the flexural-torsion buckling critical moment formula between Castellated beam and equivalent solid web beam is relevant to the diameter-depth ratio and space-depth ratio of the web. Based on the analyses, the overall stability calculation formula of solid web Beam is modified. Finally, the practical overall stability calculation formula of Castellated Beam is presented.