Frequency Analysis of Monopiles with Masing-Type Hysteresis Damping Under Large-Strain Cyclic Loading

Tott-Buswell, J.; Hilton, J.; Berberic, S.; Jalbi, S.; Prendergast, L. J.

Abstract

Offshore wind turbines supported by monopiles have demonstrated their suitability to meet sustainable energy goals. However, there remains uncertainty about how long these foundations can stay operating within serviceable deflection limits after many years at sea. In particular, storm events can impose extremely large moments about the mudline due to intense wind and wave load profiles, having irreversible effects on the soil and shifting the system’s natural frequencies. During these large oscillations, soil nonlinearity causes energy dissipation due to material damping, which must be accounted for to design against resonance. In this paper, a dynamic Winkler-type model captures nonlinear soil-structure interaction by reappropriating monotonic soil reaction curves using Masing’s rules to form discretised hysteretic stress paths. Under simple sinusoidal loading, the model displays super-harmonics in the frequency spectrum that could lead to resonance. The analysis suggests that the super-harmonic frequencies are functions of the excitation frequency for simplified loading conditions, and could be used to estimate more complex hysteretic soil-structure behaviour with structural health monitoring techniques.

Citation

Tott-Buswell, J., Hilton, J., Berberic, S., Jalbi, S., & Prendergast, L. J. (2023, August). Frequency Analysis of Monopiles with Masing-Type Hysteresis Damping Under Large-Strain Cyclic Loading. Presented at EVACES 2023, Milan, Italy

• Presentation Conference Type: Edited Proceedings
• Conference Name: EVACES 2023
• Start Date: Aug 30, 2023
• End Date: Sep 1, 2023
• Acceptance Date: Aug 2, 2023
• Online Publication Date: Aug 2, 2023
• Publication Date: 2023
• Deposit Date: Aug 14, 2023
• Publicly Available Date: Aug 15, 2023
• Publisher: Springer Nature
• Pages: 232-241
• Series Title: Lecture Notes in Civil Engineering
• Series Number: 432
• Series ISSN: 2366-2565
• Book Title: Experimental Vibration Analysis for Civil Engineering Structures
• ISBN: 9783031391088
• DOI: https://doi.org/10.1007/978-3-031-39109-5_24
• Keywords: Monopiles; Hysteresis; Natural Frequency
• Public URL: https://nottingham-repository.worktribe.com/output/23864661
• Publisher URL: https://link.springer.com/chapter/10.1007/978-3-031-39109-5_24
• Additional Information: First Online: 2 August 2023; Conference Acronym: EVACES; Conference Name: International Conference on Experimental Vibration Analysis for Civil Engineering Structures; Conference City: Milan; Conference Country: Italy; Conference Year: 2023; Conference Start Date: 30 August 2023; Conference End Date: 1 September 2023; Conference Number: 10; Conference ID: evaces2023; Conference URL: https://www.evaces2023.polimi.it/