基于模态参数的梁桥结构模型边界条件参数修正

针对实际桥梁结构复杂的边界条件,详细分析边界条件的附加约束参数。以梁桥结构的水平平动附加约束与扭转附加约束参数为讨论对象,采用最小二乘约束优化反演理论,建立以模态参数实测值与理论计算值误差平方和最小为目标的桥梁结构边界条件变异参数约束优化反演求解问题。在其基础上引入矩阵摄动理论,将结构动力方程的特征值及特征向量一阶摄动代入所建立约束优化方程,显著提高优化求解效率,并通过迭代求解的方式提高边界条件变异参数的求解精度。编制相应求解程序,通过某磁浮轨道梁方案的损伤识别验证表明,仅用前几阶仿真计算得到的模拟实测频率与振型经过4次迭代即可精确反演桥梁结构边界条件变异参数。

Updating of Boundary Conditions of Beam Bridge Structure Based on Mode Parameters

In view of the complex boundary conditions of real bridge structures,the appendix restrain parameters of structure boundary contitions were analyzed in detail.The appendix horizontal and torsional restrain parameters were selected as the research objects.The least square constrained optimization inversion method was used to establish the question of reverse of bridge structure boundary appendix parameters based on tested and calculated mode parameters.On the basis of the matrix perturbation theory,the first order eigen-value and eigen-vector were substituted into the constrained optimization inversion equation,so the solving efficiency was improved greatly,and the iteration method was used to improve the precision.The corresponding solving program was made.The example of a maglev railway girder shows that fairly good precise bridge structure boundary appendix parameters can be reserved with only several former calculated mode parameters through four times of iteration calculation.