Modal Parameter Identification Under the Non-stationary Excitation Based on the Random Decrement Method
Luo Jun 1，Liu Gang 1,2，Huang Zong-ming 1,2
1 College of Civil Engineering, Chongqing University, Chongqing 400045, China;
2 The Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry o f Education, Chongqing University, Chongqing 400045, China;
In view of the existing modal parameter identification method of stationary incentive assumed, this paper presents a modal parameter identification method under non-stationary excitation. Firstly, the variance of the mean of excitation is derived on the basis of the evolutionary spectral amplitude modulation for white noise amplitude modulation excitation, related excitation with amplitude modulation and non-stationary excitation with frequency and amplitude modulation. And then the traditional random decrement method is expanded, and the modal parameter identification problem under non-stationary excitation is transformed into a modal parameter identification problem based on the free vibration response. Finally the modal parameters are identified using the eigen-system realization algorithms. The method was verified through a numerical model of cantilever beam and a two story steel frame experiment. The identification results showed that this algorithm can accurately identify the inherent frequency and vibration mode under non-stationary excitation and the error of the identification natural frequency was less than 2%, which has a high identification accuracy.
罗钧1，刘纲1,2，黄宗明1,2. 基于随机减量法的非平稳激励下模态参数识别[J]. 振动与冲击, 2015, 34(21): 19-24.
Luo Jun 1，Liu Gang 1,2，Huang Zong-ming 1,2. Modal Parameter Identification Under the Non-stationary Excitation Based on the Random Decrement Method. JOURNAL OF VIBRATION AND SHOCK, 2015, 34(21): 19-24.
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