全桥气弹模型颤振导数识别

Identification of flutter derivatives of full-bridge aeroelastic model

将节段模型颤振导数识别方法用于全桥气弹模型,对其可行性和便利性进行详细论述;给出气弹模型模态质量的确定方法;采用随机子空间方法和随机搜索方法识别均匀流场和紊流场中苏通大桥气弹模型的18颤振导数,并和特征系统实现算法识别结果进行对比分析。研究结果表明:节段模型颤振导数识别方法是识别气弹模型颤振导数的有效和实用方法;模型模态质量可以方便地根据几何缩尺比由实桥对应值直接推算得到,且比通过模型试验实测精度更高;不同方法识别得到的均匀流场中苏通大桥气弹模型大部分颤振导数基本吻合;相对于紊流场中的气弹模型而言,均匀流场中的节段模型颤振导数识别精度更高。

The method for identification of flutter derivatives of section model is applied to a full-bridge aeroelastic model, and the feasibility and convenience of this application are elaborated. The technique for determination of the modal mass of aeroelastic model is provided. Eighteen flutter derivatives of a Sutong Bridge aeroelastic model in smooth and turbulent flows are extracted by using a stochastic search algorithm and a stochastic subspace approach, and comparative analyses are conducted with the results from using an eigen-system realization algorithm. The results indicate that it is efficient ＂and practicable to apply the identification method for flutter derivatives of section model to aeroelastic model. The modal mass of aeroelastic model can be conveniently and directly calculated by the corresponding values of actual bridge according to the geometric scale ratio, more accurate than by actual measurement in model testing. For the Sutong Bridge aeroelastie model in smooth flow, most flutter derivatives extracted by using different methods are in reasonable agreement. Identification precision of flutter derivatives of section model in smooth flow is more satisfactory than that for aeroelastic model in turbulent flow.