Identification of Modal Parameters of Closely Spaced Modes in Time Domain

• Main Authors: Chung-YiChen, 陳忠義
• Other Authors: Dar-Yun Chiang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/77135306866409799719

碩士 === 國立成功大學 === 航空太空工程學系 === 103 === Previous studies show that when a system have an repeated modes in frequency domain, the method of using multiple-input and multiple-output method can effectively identify the modal parameters. In this research, the frequency-domain theory is extended to the time domain for identification of modal parameters for systems that have repeated eignvalues.With the application of eigensystem realization algorithm method and consideration of the measurement noise, numerical simulations show that the identification result in the damping ratio is usually poor. Therefore, with the combination of concept of the correlation function in modal parameter identification, the influence of noise on identification result is reduced. The correlation matrix is also used directly to identify modal parameters, omiting the process of constructing the generalized Hankel matrix, which provides a more efficient method of identififcation of modal parameter.