任意非对称断面薄壁箱梁一维有限元分析

根据薄壁箱梁的实际支承特点,设置支承坐标系并在支承坐标系中建立变形协调的相容条件,针对任意非对称断面薄壁箱梁,导出了考虑拉(压)弯扭翘空间耦合分析的单元刚度矩阵及等效节点力公式。此外,提出了通过设置具有线刚度、转动刚度、扭翘刚度的假想弹簧单元,对薄壁箱梁的复杂约束条件进行处理的一般方法。所得到的刚度矩阵表明,只有当忽略翘曲变形对截面转角的影响时,轴向拉压才只与水平弯曲及竖向弯曲相耦合,而与约束扭转不再耦合。算例结果表明了分析方法的有效性。

ONE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THIN-WALLED BOX GIRDER WITH ASYMMETRIC CROSS-SECTIONS

A support coordinate system is established for thin-walled box girders in which the compatibility of displacements and balance of forces are met. The element stiffness matrix and equivalent joint forces are derived for thin-walled box girders with arbitrary asymmetric cross-sections to handle box girder under tension (or compression), bending, torsion and warping. In addition, a general procedure is proposed to treat the complicated constraints of thin-walled box girders by adding an assumed spring element with linear stiffness, rotational stiffness and torsion-warping stiffness. It is shown that, when the effect of warping on rotation angle is neglected, tension (or compression) is only coupled with horizontal bending and vertical bending instead of constrained torsion. The effectiveness of the analysis method is validated through numerical examplles.