多自由度结构模态阻尼比估计的新方法

A NFW METHOD OF DETERMINING MODAL DAMPINGRATIO OF IMULTDEGREE-OF-FREEDOM STRUCTURE

本文指出了利用MEM谱值比较求多自由度结构模态阻尼比方法的一些不足。在此基础上提出了一种新的求模态阻尼比的方法。文内给出了新算法的理论和计算方法,给出了计算机仿真和实测振动信号的计算实例,计算结果表明本文的方法是可行的,且具有较高的精度。本文还探讨了自回归模型的定阶问题,在AIC准则的基础上提出一种考虑信号噪声影响的定阶准则。实际应用表明新准则在各种信噪比条件下均适用。

In this paper, the method of determining damping ratio by comparing MEM spectrum is discussed and the shortcoming of this method is pointed out. Then a new method for determining damping ratio is proposed. The theory and algorithm of this method arc introduced. The results of simulation and practical computation of vibration signals show that the proposed method is efficient and accurate. In this paper the order choosing of autoregressive model is also discussed. A new criterion based on AIC is put forward, in which the influence of signal noise is considered. Practical applications show that the criterion is applicable to various SNR situationr.