梯形桁梁桥侧倾稳定分析的一种有限元法

A Finite Element Method for Analyzing the Lateral Stability of a Truss Bridge with Inclined Portals

本文将梯形桁梁桥的斜桥门架节间视作一子结构,通过其非满秩的失稳模态矩阵对子结构的刚度阵和几何刚度阵进行线性变换,得到子结构略去高阶失稳模态座标下的刚度阵和几何刚度阵;对于梯形桁梁桥的中间桁梁段则用桁梁梁段单元进行处理。这样,通过斜桥门架稳定子结构的广义位移与相邻梁段单元的广义位移之间的几何关系,即可得到计算梯形桁梁桥侧倾稳定的子结构与梁段单元相结合的有限元方法。本文给出了算例,并将结果与其它方法的结果进行了比较。结果表明,该方法具有很好的精度。

In this paper, an inclined portal panel of a truss bride with inclined portals is considered as a substructure, the generalized stiffness matrix and geometric stiffness matrix of which can be formulated by linear transforms of the stiffness matrix and geometric stiffness matrix of the substructure through a buckling mode matrix of not full rank of itself. The interior beam segment of a truss bridge is separated into generalized beam elements. Then, the sta-bility substructures and the generalized beam elements are cooperated with the help of the geometric relationship between the generalized displacements of the stability substructure and the adjacent beam segment element. Thus, a FEM ofsubstructures and beam segment elements for analyzing the lateral stability of a truss bridge with inclined portals is obtained. Finally, a numerical example is given and the obtained results are compared with those other obtained by methods. The comparison of results shows that this method is of good accuracy.