Rahman, Muhammad Syafiq Fadli (2025) Analisis Kelelahan Struktur Penopang Offshore Wind Turbine Bertipe Monopile Akibat Vortex-Induced Vibrations. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Kegagalan akibat kelelahan (fatigue failure) merupakan permasalahan krusial pada turbin angin lepas pantai, khususnya pada struktur monopile yang mengalami beban siklik akibat angin, gelombang, dan arus laut. Kode desain terbaru untuk turbin angin seperti DNV RP-C203, tidak mempertimbangkan fenomena vortex-induced vibrations (VIV). Dalam tugas akhir ini, pengaruh VIV pada monopile diamati dalam bentuk gaya angkat (lift force) yang tegak lurus terhadap arah aliran melalui simulasi computational fluid dynamics (CFD), dan kemudian diperhitungkan ke dalam estimasi umur kelelahan untuk melihat signifikansinya. Selanjutnya, alternatif desain berupa helical strake dengan 1 dan 3 sirip dipasang pada monopile, dan pengaruh VIV terhadap umur kelelahan juga dianalisis. Tugas akhir ini menemukan bahwa, dibandingkan dengan perhitungan yang tidak memasukkan pengaruh VIV, tidak terdapat peningkatan signifikan terhadap umur kelelahan (92,2 tahun), dengan peningkatan tegangan von Mises hanya pada orde 10⁻⁵. Selain itu, penggunaan helical strake dengan 1 sirip dan 3 sirip masing-masing meningkatkan umur kelelahan menjadi 92,3 tahun dan 93,2 tahun atau peningkatan sebesar 0,0926% dan 1,0165%.
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Fatigue failure is a critical concern in offshore wind turbines, particularly for monopile-supported structures subjected to cyclic loading from wind, waves, and ocean currents. Recent codes for designing wind turbines like the DNV RP-C203, however, does not take into consideration the phenomenon of vortex-induced vibrations. In this final project, the effects of vortex-induced vibrations on monopiles are observed in the form of the lift force perpendicular to the flow through computational fluid dynamics, and is included in fatigue life estimation to observe the significance of its effects. Then, a further design alternative in the form of 1-fin and 3-fin helical strakes on the monopile is applied, and the effects of VIV on fatigue life are also estimated. This final project finds that when compared to calculations not including the effects of VIV, there is no significant increase to the fatigue life of 92,2 years, and it was found that the von mises stress increased only by the order of 1e-5. Furthermore, this final project finds that the usage of 1-fin helical and 3-fin helical strakes have increased fatigue lifespan to 92,3 and 93,2%, an increase by 0,0926% and 1,0165% respectively.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | vortex-induced vibrations, computational fluid dynamics, kelelahan, fatigue, turbin angin lepas pantai, offshore wind turbine, monopile |
| Subjects: | T Technology > T Technology (General) T Technology > TC Hydraulic engineering. Ocean engineering > TC1665 Offshore structures--Materials. |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Muhammad Syafiq Fadli Rahman |
| Date Deposited: | 25 Jul 2025 08:19 |
| Last Modified: | 25 Jul 2025 08:19 |
| URI: | http://repository.its.ac.id/id/eprint/121576 |
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