摘要
在悬索桥的有限元计算中往往忽略鞍座对主缆的影响而直接采用成桥理论IP点建模,这种简化会对主缆线形计算带来误差。为提高有限元计算悬索桥主缆线形的精度,提出一种能精确模拟主缆和鞍座约束关系的3节点单元——鞍座单元。采用该单元可基于弹性悬链线的解析解迭代出主缆与鞍座的切点坐标,再根据该单元刚度矩阵元素的含义并利用静力平衡条件直接推导出其切线刚度矩阵。以国内某主跨1 650 m的悬索桥为例,将鞍座单元的切线刚度矩阵引入到该桥有限元整体计算中,计算结果表明,鞍座单元能精确模拟主缆与鞍座的实际情况,将其引入悬索桥的结构计算中能大幅度提高计算精度。
In the finite element calculation of suspension bridge, the impact of saddle on main cables is often ignored while the theoretic IP point of completed bridge will be directly used to establish models, which may result in errors in the calculation of geometric shape of the main cables owing to the simplifying. To enhance the calculation accuracy of the geometric shape of the main cables by the finite element method, a type of the 3-node element, that is, the saddle element, which can accurately simulate the restrain relation between the main cables and saddle is proposed. With the proposed element, the tangent coordinate of the main cables and saddle can be iterated on the basis of the analytic solution of elastic catenary. The tangent stiffness matrix can be then directly derived in accordance with the implication of the stiffness matrix elements of the proposed element and also by using the static balance conditions. By way of example of a domestic suspension bridge with a main span 1 650 m, the tangent stiffness matrix of the proposed element is introduced into the finite element global, calculation of the bridge. The results of the calculation show that the proposed element can accurately simulate the actual situations of the main cables and saddle and the introducing of the element into the structural calculation of suspension bridge can greatly enhance the calculation accurcy.
出处
《桥梁建设》
EI
CSCD
北大核心
2011年第1期35-38,47,共5页
Bridge Construction
关键词
悬索桥
鞍座
主缆
悬链线
刚度矩阵
suspension bridge
saddle
main cable
catenary
stiffness matrix
