【摘要】 大跨桥梁结构中的移动荷载识别是结构健康监测的重要组成部分之一,其作为动力学中的反问题,存在唯一性及稳定性等病态问题。本文首先推导出移动荷载作用下结构响应的卷积形式的离散公式,然后利用有限元理论中的形函数拟合移动荷载,推导出基于荷载形函数的移动荷载识别表达式。将移动荷载的识别转化为荷载形函数拟合系数的识别,降低了需要识别的未知量,减小了逆运算的计算量,消除或减弱逆问题病态性,并提高了计算效率。利用某大跨刚构-连续预应力混凝土桥梁修正后的有限元模型进行数值仿真,考虑路面粗糙度,由模态叠加法计算移动荷载作用下的响应;然后采用荷载形函数方法识别移动荷载,证明该方法在5%以下的噪声时能快速并精确识别复杂桥梁结构的移动荷载。更多还原

【Abstract】 Moving force identification of long-span bridges is an important part of structural health monitoring,and as an inverse problem,it is ill-conditioning with uniqueness and stability problems.This paper deduced the discretized formulation of structure responses to moving force,employed the shape functions from the finite element method to fit the time history of moving force,and developed the moving force identification formulas based on load shape functions.The identification problem of moving force was transformed into determining the fitting coefficients of load shape functions,which decreased the unknown parameters,reduced calculation in the matrix inverse operation,removed or weakened the ill condition and promoted computational efficiency.To evaluate the proposed algorithm,a prestressed rigid-continuous concrete bridge was simulated by its modified finite element model,which subjected to moving force considering road roughness.The responses were analyzed by mode superposition technique,and moving force was estimated by load shape functions.Results show that the moving force with noise below 5% can be identified for complex bridges efficiently and accurately.更多还原