摘要
桥梁设计阶段构件参数的改变、施工阶段体系的转换和施工误差、使用过程中的磨损、损伤都会直接造成桥梁质量阵、刚度阵的改变,其动力特性也随之改变。遇到结构参数频繁小幅变化的情形,用经典的方法获得其动力特性就需要多次求解广义特征问题,这对于大型复杂结构来说是非常麻烦和费时的。提出应用矩阵摄动法来求解桥梁结构改变后的固有模态。用ANSYS对某悬索桥进行自由振动分析,然后以从分析结果中提取出的频率、刚度阵、质量阵及振型数据为基础,采用矩阵摄动法对结构参数小幅度调整后的固有模态进行相应的计算,并将所得结果与结构修改后的有限元计算结果进行比较。结果表明本文所提出的应用矩阵摄动法修正固有模态的方法是有效的、可靠并且省时的,便于工程应用。
Modification of element parameters at design stage, system transformation and construction error, any structural abrasion and damage during the service stage will directly alter the mass and stiffness matrices of a bridge. Correspondingly, bridge＇s dynamic properties may also change. When structural parameters vary frequently in small magnitudes, one may have to solve for the generalized eigen-value problems several times in order to acquire the dynamic properties of a bridge. Obviously, this undertaking is very tedious and time consuming, especially when the bridge structure is large and complex. Presented in the paper is a matrix perturbation method for calculating the natural vibration modes of a bridge structure with parametric modifications. To demonstrate the proposed method, the free vibration analysis of a suspension bridge is carried out using ANSYS. Then, using the frequencies, stiffness matrix, mass matrix and vibration shapes abstracted from the analysis, the matrix perturbation method is adopted to compute natural modes of the structure with small parametric adjustments. The results are compared with those from the finite element method, and it indicates that the proposed method is quite effective, reliable, efficient and convenient for design applications.
出处
《土木工程学报》
EI
CSCD
北大核心
2006年第4期32-34,53,共4页
China Civil Engineering Journal
关键词
悬索桥
固有模态
参数修改
矩阵摄动法
suspension bridge
natural modal
parameter modification
matrix perturbation method
