基于多项式响应面算法的斜拉桥静动力模型修正研究

Study of Static and Dynamic Model Modification of Cable-stayed Bridge Based on Multinomial Response Surface Algorithm

为保证建立的桥梁有限元模型静动力特性符合实际情况,基于响应面法对某双塔斜拉桥有限元模型进行多目标的优化设计修正,根据工程经验,选取主梁弹性模量、斜拉索弹性模量、斜拉索密度3种参数,采用中心组合设计方法从中选取试验点,建立响应面数学模型,根据实测桥梁静动力试验数据,对模型的静动力参数进行相关性分析,并对拟合的响应面函数评价,对响应面模型的一致性进行检验。比较优化前后的桥梁模型静动力各项数据:其一阶频率相关性提高10%,最不利工况下跨中位移的相关性提高了32%,证明修正后的模型静动力特性与实测值吻合度较高,较常规模型修正方法节约了优化时间。

To ensure the static and dynamic characteristics of the bridge finite element model can consist with the actual situation,based on the response surface method,the finite element model of a double-tower cable-stayed bridge was modified with a multinomial optimization design.According to the engineering experience,using three parameters of elastic modulus of the main girder,elastic modulus of the stay cable,and density of the stay cable,the central composite design was adopted to select the testing point and to establish the mathematical model of the response surface.Based on the static and dynamic test data of the bridge,the correlation analysis of the static and dynamic parameters of the model was carried out,and the fitted response surface function was evaluated,to verify the consistency of the response surface model.Comparing the static and dynamic data of the bridge model before and after the modification,it can be seen that the correlation of the first-order frequency was increased by 10%,and the correlation of the mid-span displacement was increased by 32% under the most unfavorable conditions,which proved that the static and dynamic characteristics of the modified model well fitted the measured data,and the optimization time was saved compared with the conventional model modification method.