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本文研究了ARMA模型对钢桥振动模态参数的识别,一种是ARMA1法,利用修正的Yule-Walker方程直接求出ARMA模型中的AR参数,并利用这些参数求出结构的固有频率;第二种是ARMA2法,首先粗略地估计出模型中的参数然后通过非线性迭代得到一定精度的估计值,最后利用这些参数计算结构的固有频率。本文采用这两种力法,除对仿真数据进行验证分析外,还对斜腿刚构铁路钢桥模型的瞬态冲击短信号进行了分析,同时与AR法、MEM法和FFT等方法进行了对比,特别是与频域FFT方法的对比,可以认为对短瞬态信号采用时域法分析的频率精度远优于FFT法的结果。
In this paper, ARMA model is used to identify the vibration modal parameters of steel bridge. One is ARMA1 method. The AR parameters in ARMA model are obtained directly by the modified Yule-Walker equation. The natural frequencies of the structure are obtained by using these parameters. The two methods are ARMA2 method. Firstly, the parameters in the model are roughly estimated and then some accurate estimates are obtained by nonlinear iteration. Finally, the natural frequency of the structure is calculated by these parameters. In addition to verifying and analyzing the simulation data, the transient force short signal of the rigid-framed steel railway bridge with inclined legs is analyzed in this paper. At the same time, with the method of AR, MEM and FFT In contrast, especially in comparison with the frequency-domain FFT method, it can be considered that the frequency accuracy of the time-domain analysis of the short transient signal is far superior to that of the FFT method.