Dynamic Characterization of Structures from Limited Measurements Using a Subspace System Identification Method
- PDF / 5,034,874 Bytes
- 19 Pages / 595.276 x 790.866 pts Page_size
- 94 Downloads / 194 Views
ORIGINAL RESEARCH
Dynamic Characterization of Structures from Limited Measurements Using a Subspace System Identification Method Boyoung Kim1 · Jun Won Kang1 · Keunhee Cho2 Received: 13 October 2020 / Revised: 30 October 2020 / Accepted: 3 November 2020 © Korean Multi-Scale Mechanics (KMSM) 2020
Abstract In this study, we investigate a subspace-system identification method that estimates the modal characteristics and damping ratio of structures using a small number of sensor measurement responses. With this method, a Kalman state vector is first constructed from the input and measurement data, and then the state-space system matrix is optimized from it. For this purpose, a block Hankel matrix is constructed using the input data of the load applied to the structure and the measurement data of the response, and then the matrix is decomposed through QR factorization. Then, singular value decomposition is used to obtain the extended observability matrix and state-space system order n , and the state-space system matrix constituting the Kalman state vector is obtained via least-squares optimization. The natural frequency and damping ratio of the structural system are calculated from the eigenvalue of the obtained system matrix. To verify the effectiveness of this subspace state-space system identification method, the natural frequency and mode shape of a simply supported beam and cantilever beam were calculated using a limited number of measurement data, and the results were compared with an exact solution to evaluate the accuracy of the estimation results of the dynamic characteristics. Furthermore, the modal characteristics and damping ratio of a real bridge were estimated from acceleration data. The stability chart calculated from the example shows that the subspace state-space system identification method discussed in this study can accurately identify the modal characteristics of structures using only a small number of measurement data. Keywords State-space system identification · Block Hankel matrix · Singular value decomposition · Modal characteristics · Stability chart
Introduction System identification from the perspective of structural health monitoring is a computational method that uses measurement data to evaluate the dynamic characteristics and stability of structures. The increased length and flexibility of bridges has led to more frequent abnormal vibrations. Therefore, there is growing interest in evaluating the dynamic characteristics of structures in civil engineering. Recently, several studies on such system identification algorithms have been conducted, and one of the remarkable among them is a method to effectively estimate the higher mode natural * Jun Won Kang [email protected] 1
Department of Civil Engineering, Hongik University, Seoul 04066, Korea
Structural Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology, Goyang‑si, Gyeonggi‑do 10223, Korea
2
frequency and mode shape of structures using a wireless measurement system [2]. Representa
Data Loading...
