索桥结构的非线性有限元法

Nonlinear Finite Element Method of Cable-Bridge's Structures

结合新型倒张拱索桥结构特点,考虑索桥非线性大变形性质,提出三节点二次曲线元,直梁单元和杆单元共存的混合单元有限元模式,从结构整体上模拟索桥.由 Reissner 广义变分原理导出曲线元,梁单元的刚度矩阵,并得到用节点坐标表示的大位移空间杆的单元刚度矩阵,实现了索、梁、杆单元的位移协调,得到整体规模下的有限元运动方程.用 Newton-Raphson 方法求解静力问题.实例的计算结果与实测值对比吻合较好,表明方法是正确和可行的.

According to structural properties of new type inverse tensional arch cable-bridge and the large deformational nature of bridge,We propose mixed finite element method combining quadratic crrve ele- ment,straight beam element and space rod element in one modal.Stiffness matrices of quadratic curve el- ement,beam element and element expressed node's of node's displacements among three kinds of element and obtain finite element kinetic equations using Reissner's generalized variational principle.The finite el- ement equilibrium equations are solved with Nowton-Raphson scheme.Calculating results of real exam- ple are good coincide eith experimental results,It is show that the method is correct and usable.