增设广义位移下箱梁剪力滞效应的变分法

Variational Method of Shear Lag Effect of Box Beams with Adding Generalized Displacement Assumptions

考虑荷载横向移动时顶板、底板剪力滞效应的不同,及腹板剪力在剪切变形中做功效应的影响,根据以往学者得出的试验效果良好的三次抛物线型,分设不同的纵向位移函数,取4个独立的广义位移对箱梁的剪力滞效应进行分析.由最小势能原理,建立关于不同位移的微分方程及自然边界条件.公式演引过程表明,剪力滞效应与腹板剪切效应独立存在;求解结果表明,所演引的公式更符合实际结构应力及位移分布情况,具有较高的实用价值.

The top plate and bottom plate of box beams behave different shear lag effects when the symmetric load moves along the cross section.The web shear＇s work on the shearing deformation is taken.Based on the previous research and conclusion on the shear lag effect experiment,cubic parabola displacement function is adopted.Considering the top and bottom plate＇s different longitudinal displacements,four independent generalized displacements are taken to analysis the shear lag of box beams.Based on the principle of minimum potential energy,displacement differential equations and natural boundary conditions are formed respectively.Formula derivation process shows that shear lag effect and web shear deformation work independently.The computation results indicate that the derivation formulas can improve calculation accuracy.