Altavillah, Rachmat (2015) Analisa Pengaruh Variasi Marine Growth Terhadap Respon Dinamik Dan Kelelahan Berbasis Resiko Pada Struktur Jacket. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Marine growth merupakan massa non-struktural tambahan dan menyebabkan peningkatan beban gelombang pada struktur. Penambahan marine growth berdampak pada perubahan massa struktur (lebih berat) sehingga menyebabkan perubahan respon struktur tersebut terhadap beban-beban dinamis yang diterimanya. Pada penelitian ini struktur yang dipakai adalah Bekapai L “BL” yang akan divariasikan bentuk marine growth-nya. Penelitian ini bertujuan untuk menganalisa apakah variasi bentuk marine growth dapat menyebabkan perubahan terhadap respon dinamik dan kelelahan suatu struktur. Respon dinamik dalam penelitian ini ditinjau dari respon gerak struktur dengan variasi frekuensi periode gelombang yang menghasilkan defleksi. Dari analisa didapatkan defleksi pada sambungan 6178 arah gelombang dominan 0o untuk model 1 adalah 21,102 cm, 20,998 cm pada model 2, 20,942 cm pada model 3, 20,919 pada model 4, dan 20,348 cm pada model 5. Sedangkan dari hasil analisa kelelahan didapatkan umur kelelahan terkecil terdapat pada sambungan 315-316. Pada model 1 didapatkan umur kelelahan sebesar 19,088 tahun, 25,290 tahun pada model 2, 31,330 tahun pada model 3, 33,279 tahun pada model 4, dan 37,894 tahun pada model 5. Dari hasil komparasi diatas dapat disimpulkan bahwa dengan variasi bentuk Marine Growth dapat memberikan perbedaan terbesar terhadap periode natural dan defleksi maksimum pada model 1 & 5, yaitu sebesar 1,73% dan 3,71%. Sedangkan terhadap umur kelelahan memiliki perbedaan sebesar 98,52%. Untuk menentukan langkah lebih lanjut dalam integritas struktur dilakukan analisa resiko. Probability of failure (PoF) ditentukan dengan metode Monte Carlo yang menghasilkan PoF sambungan 315-316 pada model 1 sebesar 0.5189, model 2 sebesar 0,4798, model 3 sebesar 0,4541, model 4 sebesar 0,4241, dan model 5 0,4133. Sedangkan Consequence ditetapkan berdasarkan masing-masing kondisi struktur berdasarkan API pada setiap pemodelan. Didapatkan resiko berdasarkan API adalah resiko tinggi pada model 1 dan resiko menengah pada model 2,3,4 dan 5.
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Marine growth is an additional non-structural mass which can causing increase of wave loads on a structure. Marine growth addition affects on structural mass (become heavier), causing changes on its structural response to dynamic loads. In this study, the structure is Bekapai L “BL” platform which would be variated by marine growth’s forms. The purpose of this study are to analyze whether variations of marine growth can effect to dynamic response and fatigue life of the structure. The dynamic response in this analysis is reviewed by structural motion response with wave period/frequency variation with deflection as the result. From the analysis we got the deflection of joint 6178 with dominant wave direction from 0 o for the 1st model is 21.102 cm, 20.998 cm for 2nd model, 20.942 cm for 3rd model, 20.919 cm for 4th model, and 20.348 cm for 5th model. The results of fatigue analysis obtained joint 315-316 as the most critical. Fatigue life obtained for 1st model is 19.088 years, 25.290 years for 2nd model, 31.330 years for 3rd model, 33.279 years for 4th model, and 37.894 years for 5th model. From the comparison can be concluded that the variations in the form of Marine Growth effect the most to the natural period and maximum deflection, which found in the 1st and 5th model with 1.73% and 3.71% changes. While on the fatigue life has a 98.52% difference. Risk analysis is used to determine a further step in the structural integrity. Probability of failure (POF) is determined by the Monte Carlo method which produces PoF in joint 315-316 for 1st model is 0.5189, 0.4798 for 2nd model, 0.4541 for 3rd model, 0.4241 for 4th model, and 0.4133 for 5th model. While the Consequence is different on each structural modelling condition based on the API. The result from API risk matrix is high risk for the 1st model and medium risk for 2nd, 3rd, 4th and 5th models.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 627.98 Alt a |
| Uncontrolled Keywords: | Variasi Marine Growth, Respon Dinamik, Fatigue, Resiko |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Yeni Anita Gonti |
| Date Deposited: | 01 Apr 2020 03:51 |
| Last Modified: | 01 Apr 2020 03:51 |
| URI: | http://repository.its.ac.id/id/eprint/75635 |
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