均布荷载作用下门式刚架的平面内稳定性能

In-plane stability performance of portal frame structures with different ratio of depth to span

应用ANSYS有限元程序,在均布荷载作用下,对不同高跨比、梁柱截面的门式刚架进行弹性几何非线性分析,根据荷载位移曲线得出弹性屈曲荷载。分析表明,当刚架高跨比大于等于1∶3时,刚架失稳模式为侧移失稳,可忽略梁中主弯矩和梁轴力对刚架稳定性的影响;当刚架高跨比小于1∶3时,刚架的失稳模式同刚架高跨比、梁柱线刚度比均有关系。刚架的失稳模式常为对称失稳,此时,梁中主弯矩和梁轴力对刚架稳定性的影响不可忽略。

The ANSYS finite element program is used to perform geometrically nonlinear analysis in order to deal with the in-plane stability of the steel portal frames with different ratio of depth to span in which the section sizes of the beam and the column are different, The stability behavior of portal frame subjected to roof uniform loading is investigated and the instability load is obtained by analyzing the load-deflection curves. It is indicated that when the ratio of depth to span is equal to or larger than 1∶3, the instability mode is sides-away buckling, and the main moment and axial force in the beam have a negligible effect on stability of the portal frame?When the ratio of depth to span is less than 1∶3, the instability mode of the portal frame is associated with the ratio of depth to span?stiffness factor ratio of beam to column,the instability mode of the portal frames is mostly symmetric, and the above-mentioned effect of main moment and axial force on the stability behavior of portal frame can not be negligible.