Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation
Commonly used methods for identifying modal parameters under environmental excitations assume that the unknown environmental input is a stationary white noise sequence. For large-scale civil structures, actual environmental excitations, such as wind gusts and impact loads, cannot usually meet this c...
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MDPI AG
2025-01-01
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| author | Jinzhi Wu Jie Hu Ming Ma Chengfei Zhang Zenan Ma Chunjuan Zhou Guojun Sun |
| author_facet | Jinzhi Wu Jie Hu Ming Ma Chengfei Zhang Zenan Ma Chunjuan Zhou Guojun Sun |
| author_sort | Jinzhi Wu |
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| description | Commonly used methods for identifying modal parameters under environmental excitations assume that the unknown environmental input is a stationary white noise sequence. For large-scale civil structures, actual environmental excitations, such as wind gusts and impact loads, cannot usually meet this condition, and exhibit obvious non-stationary and non-white-noise characteristics. The theoretical basis of the stochastic subspace method is the state-space equation in the time domain, while the state-space equation of the system is only applicable to linear systems. Therefore, under non-smooth excitation, this paper proposes a stochastic subspace method based on RDT. Firstly, this paper uses the random decrement technique of non-stationary excitation to obtain the free attenuation response of the response signal, and then uses the stochastic subspace identification (SSI) method to identify the modal parameters. This not only improves the signal-to-noise ratio of the signal, but also improves the computational efficiency significantly. A non-stationary excitation is applied to the spatial grid structure model, and the RDT-SSI method is used to identify the modal parameters. The identification results show that the proposed method can solve the problem of identifying structural modal parameters under non-stationary excitation. This method is applied to the actual health monitoring of stadium grids, and can also obtain better identification results in frequency, damping ratio, and vibration mode, while also significantly improving computational efficiency. |
| format | Article |
| id | doaj-art-68da93662a754444addfaa1efbc62acc |
| institution | OA Journals |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | Applied Sciences |
| spelling | doaj-art-68da93662a754444addfaa1efbc62acc2025-08-20T02:12:40ZengMDPI AGApplied Sciences2076-34172025-01-01153139810.3390/app15031398Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary ExcitationJinzhi Wu0Jie Hu1Ming Ma2Chengfei Zhang3Zenan Ma4Chunjuan Zhou5Guojun Sun6State Key Laboratory of Building Safety and Built Environment & National Engineering Research Center of Building Technology, Beijing 100013, ChinaCollege of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, ChinaState Key Laboratory of Building Safety and Built Environment & National Engineering Research Center of Building Technology, Beijing 100013, ChinaCollege of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, ChinaCollege of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, ChinaShaanxi Academy of Building Research Co., Ltd., Xi’an 710082, ChinaCollege of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, ChinaCommonly used methods for identifying modal parameters under environmental excitations assume that the unknown environmental input is a stationary white noise sequence. For large-scale civil structures, actual environmental excitations, such as wind gusts and impact loads, cannot usually meet this condition, and exhibit obvious non-stationary and non-white-noise characteristics. The theoretical basis of the stochastic subspace method is the state-space equation in the time domain, while the state-space equation of the system is only applicable to linear systems. Therefore, under non-smooth excitation, this paper proposes a stochastic subspace method based on RDT. Firstly, this paper uses the random decrement technique of non-stationary excitation to obtain the free attenuation response of the response signal, and then uses the stochastic subspace identification (SSI) method to identify the modal parameters. This not only improves the signal-to-noise ratio of the signal, but also improves the computational efficiency significantly. A non-stationary excitation is applied to the spatial grid structure model, and the RDT-SSI method is used to identify the modal parameters. The identification results show that the proposed method can solve the problem of identifying structural modal parameters under non-stationary excitation. This method is applied to the actual health monitoring of stadium grids, and can also obtain better identification results in frequency, damping ratio, and vibration mode, while also significantly improving computational efficiency.https://www.mdpi.com/2076-3417/15/3/1398modal parameter identificationnon-stationary excitationrandom decrement techniquestochastic subspace identification methodRDT-SSI |
| spellingShingle | Jinzhi Wu Jie Hu Ming Ma Chengfei Zhang Zenan Ma Chunjuan Zhou Guojun Sun Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation Applied Sciences modal parameter identification non-stationary excitation random decrement technique stochastic subspace identification method RDT-SSI |
| title | Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation |
| title_full | Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation |
| title_fullStr | Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation |
| title_full_unstemmed | Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation |
| title_short | Modal Parameter Identification of the Improved Random Decrement Technique-Stochastic Subspace Identification Method Under Non-Stationary Excitation |
| title_sort | modal parameter identification of the improved random decrement technique stochastic subspace identification method under non stationary excitation |
| topic | modal parameter identification non-stationary excitation random decrement technique stochastic subspace identification method RDT-SSI |
| url | https://www.mdpi.com/2076-3417/15/3/1398 |
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