Modal parameter identification via robust second-order blind identification method
FU Zhi-chao1;CHENG Wei1;XU Cheni2
1. School of Aeronautic Science and Engineering, Beijing University of Aeronautics and Astronautics, Bei-jing 100191, China;2. North China Power Engineering (Beijing) CO., LTD, Beijing 100011, China
Abstract:In this paper, a robust second-order statistical method employed in blind source separation (BSS) is adapted for use in modal parameter identification. Firstly, modal responses are estimated by the application of robust second-order blind identification(R-SOBI) technique on the measured vibration signals. And then mode shapes are extracted from the de-mixing matrix above. Finally, Frequency and damping ratios can be obtained from the modal responses by simple single degree of freedom methods. Numerical evaluations demonstrate that the proposed method provides a novel and robust approach to modal identification. Especially the mode shapes could be extracted exactly even under low signal to noise rate (SNR) case.