基于优化设计理论的桥梁有限元模型修正

为改善桥梁有限元建模的精度,降低理论模型计算结果与实验结果之间的误差,采用模型修正技术对建立的初始有限元模型进行修正.利用桥梁模态参数识别结果,以频率残差和实测自由度上振型分量残差加权和最小为优化计算目标,无须振型扩阶,避免了由此引入误差的影响.依据工程经验对修正参数和频率变动施以约束条件,将有限元模型修正问题归结到约束优化问题.问题的求解采用基于梯度下降的优化迭代算法.仿真结果表明,经过修正后的有限元计算模型计算结果与实验结果非常接近.可以应用于动力实验模型修正.

Updating of bridge finite element model based on optimization design theory

To improve the precision of finite element model and reduce the discrepancy between the theoretical calculation result and test result,the finite element model update technique is used to modify the original finite element model.This arithmetic took the minimization of summation of frequency discrepancy and modal shape displacement as its optimizing goal,set restrictive conditions to parameter modification and frequency change by engineering experience,and ranged model updating to restriction optimization.It was resolved by the optimized iteration of gradient decent method.Simulation proves that the model calculation result is close to the test result after updating.The proposed finite element model updating technology of parametrical bridge based on optimization design theory can be used to dynamic test model update.