基于时间元模型的复杂桥梁结构移动荷载识别

Identification of Moving Loads for Complex Bridge Structures Based on Time Finite Element Model

为研究桥梁结构在移动车辆荷载反复作用下的疲劳损伤机理,利用有限元法建立复杂桥梁结构模型,同时为提高计算精度,承载主梁单元形函数采用5次Hermitian插值函数,并得到桥梁的离散振型与模态参数；利用归一化的第(?)类Chebyshev正交多项式作为响应和荷载的时间有限元形函数,基于加权残值法建立了移动荷载识别的时间元模型；为解决荷载识别的不适定性,利用截断奇异值分解的正则化方法由应变和位移响应得到移动荷载的稳定解,数值分析结果表明,该方法能有效地识别复杂结构的移动荷载,识别精度高,抗干扰能力强．

The identification of moving loads can be used to investigate the fatigue or damage mechanism of complex bridge structure under the repeated action of moving vehicle loads. In this paper, the structural model of complex bridge is established using the finite element method, and to increase the computation accuracy, the quintic Hermitian interpolating function is adopted as element shape function of the load-bearing main girder. The discrete modes and modal parameters of bridge structure are also obtained. The first kind of Chebyshev orthogonal polynomial is normalized and taken as the time finite element shape function of responses and forces, and the time finite element model of moving loads identification is established based on the weighted-residual method. Then moving loads are identified from the strain and displacement responses, and the truncated singular value decomposition regularization method is used to obtain the stable solution, which solves the intrinsical ill-posed problem of load identification. The simulated results show that the proposed method may effectively identify the moving loads on complex bridge structures with high identification accuracy and powerful noise-proof performance.