Abstract
In the actual measurement of offshore wind turbines (OWTs), the measured accelerations usually contain a large amount of noise due to the complex and harsh marine environment, which is not conducive to the identification of structural modal parameters. For OWTs with remarkably low structural modal frequencies, displacements can effectively suppress the high-frequency vibration noise and amplify the low-frequency vibration of the structure. However, finding a reference point to measure structural displacements at sea is difficult. Therefore, only a few studies on the use of dynamic displacements to identify the modal parameters of OWTs with high-pile foundations are available. Hence, this paper develops a displacement conversion strategy to study the modal parameter identification of OWTs with high-pile foundations. The developed strategy can be divided into the following three parts: zero-order correction of measured acceleration, high-pass filtering by the Butterworth polynomial, and modal parameter identification using the calculated displacement. The superiority of the proposed strategy is verified by analyzing a numerical OWT with a high-pile foundation and the measured accelerations from an OWT with a high-pile foundation. The results show that for OWTs with high-pile foundations dominated by low frequencies, the developed strategy of converting accelerations into displacements and then performing modal parameter identification is advantageous to the identification of modal parameters, and the results have high accuracy.
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Acknowledgements
The authors acknowledge the financial support of the National Natural Science Foundation of China (Nos. 5207 1301, 51909238 and 52101333), the Zhejiang Provincial Natural Science Foundation of China (No. LHY21E0900 01), the Zhejiang Provincial Natural Science Foundation of China (No. LQ21E090009), and the support of the research on structural modeling analysis for the offshore wind turbines subjected to the multi-source coupled factors with the ship collision safety evaluation funded by Powerchina Huadong Engineering Corporation Limited.
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Li, Y., Wang, B., Liu, Q. et al. Application of Converted Displacement for Modal Parameter Identification of Offshore Wind Turbines with High-Pile Foundation. J. Ocean Univ. China 21, 1467–1478 (2022). https://doi.org/10.1007/s11802-022-4943-0
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DOI: https://doi.org/10.1007/s11802-022-4943-0