舰用燃气轮机框架模型的模态参数识别

APPLICATION OF MULTIMODE DIRECT FITTING METHOD IN MODAL IDENTIFICATION OF THE BASE OF GAS TURBINE

本文采用一种有理正交多项式──多模态曲线拟合法对一舰用燃气轮机框架模型进行了实验模态分析。以Ｆｏｒｓｙｔｈｅ复正交多项式作为频响函数的理论值，用实测的频响函数建立系数矩阵，来寻找使目标函数最小的最优值。本文在ＨＰ９８２６微机上建立了测试、数据采集及参数识别等系统识别软件。给出了具有工程实用意义的前五阶振动模态参数，识别结果和有限元计算相比较，令人满意。

In the paper, an orthogonal polynomial analysis method-Multimode Direct Fitting Method is developed. Taking the model base of a marine gas turbine as an example, the measured Transfer Functions are used to establish the coefficient matrix and the Forsythe Orthogonal Polynomial is adopted in the identification of the modal parameters of the frame. The complete analysis software of modal identification in frequency domain induding the software of data acquisition and parameter estimation has been estab fished on a HP9826 personal computer. The agreement between the identified results and that of the finite element analysis shows that the estimation is effective and satifactory. The modal parameters of first 5 orders which are of practical significance in engineering have been successfully obtained in the experiment.