2021 Fiscal Year Research-status Report
Real-time hysteresis identification in controlled structures based on restoring force reconstruction and Kalman filter
| Project/Area Number |
21K14284
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| Research Institution | Tohoku University |
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Principal Investigator |
郭 佳 東北大学, 災害科学国際研究所, 助教 (50868081)
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| Project Period (FY) |
2021-04-01 – 2023-03-31
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| Keywords | Identify hysteresis / Kalman filter / Force reconstruction / Bayesian estimation / Data-driven approach |
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| Outline of Annual Research Achievements |
Identifying the hysteretic behaviors in structures plays a significant role in seismic design and analysis. This research develops a new hysteresis identification framework where rather than identifying the hysteretic parameters, the restoring forces are reconstructed so as to identify the hysteretic loops. Under this new framework, there is no need to get a priori knowledge on the hysteretic models, enabling a wider range of applications, and the involved system equation is linear with unknown restoring forces, tending to be more efficient. Then, the Kalman filter is adopted for real-time restoring force reconstruction because the Kalman filter is celebrated for its efficiency, effectiveness and reliability in linear system estimation with noisy measured data. In doing so, the restoring forces are additionally augmented as state variables and such augmentation is shown to act as the role of Tikhonov regularization, by which the proper covariance of the augmentation as the regularization parameter is selected via the L-curve method. Numerical examples are presented and experimental tests are conducted to verify the effectiveness and robustness of the proposed real-time hysteresis identification method.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In 2021, a real-time hysteresis identification method has been successfully established based on restoring force reconstruction and the Kalman filter. In this way, a traditional search for the optimal hysteretic parameters is avoided so that a priori knowledge on the hysteretic models is no longer needed and moreover, only the linear system equation is involved. Then, the Kalman filter is adopted for restoring force reconstruction and it is shown that the additional augmentation of the restoring forces as state variables acts as the role of Tikhonov regularization. Due to the regularization effect, an optimal covariance matrix for the process noise of the restoring forces is selected by the L-curve method. Numerical examples of a seven-story shear building with different kinds of hysteretic models are explored and results show that the proposed method can well identify the hysteretic behaviors of various hysteretic models, and the L-curve criterion indeed works well in selecting a proper covariance matrix for restoring force evolution.
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| Strategy for Future Research Activity |
In 2022, dynamic tests of a controlled structure will be conducted at the structural laboratory in Tohoku University so as to validate the proposed real-time hysteresis identification method. Moreover, the proposed method will be applied to link the field measurements in the structural health monitoring (SHM) system to the characteristics of a real high-rise building. Other data-driven identification approaches, e.g. UKF, sparse regression and deep learning methods, will also be compared with this method.
In addition, the researching outcome in both of 2021 and 2022 will be summarized and submitted to international academic journals. Presentations at national and international conferences are also being planned.
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| Causes of Carryover |
設備備品費：試験体の加速度計測ため、動ひずみ測定器5台、マルチデータ収集システム（計測用ノートPC、PCインターフェースユニット、高機能PC ソフト、ACアダプタ、高速アンログ計測ユニット、ひずみ計測ユニット）、高感度加速度計２台を調達する．試験体の動変位計測に、レーザ変位計（センサベッド、アンプユニット、センサベッドケーブル、電源ユニット、電源アンプ架台）２セットを調達する．
消耗品費：振動台実験のため、既存小型三層試験体を改修することを想定した．
人件費：2年目に実施する実験は、組立・解体を専門業者（30千円/日×2日×2人）に依頼する．
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