Analisis Kelelahan Rantai Tali Tambat Pada Single Point Mooring Akibat Pengaruh Laju Korosi Dengan Pendekatan Combined Spectrum

Paramartha, I Gede Adhi (2025) Analisis Kelelahan Rantai Tali Tambat Pada Single Point Mooring Akibat Pengaruh Laju Korosi Dengan Pendekatan Combined Spectrum. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Floating Storage and Offloading (FSO) merupakan struktur terapung yang berfungsi menerima, menyimpan, dan menyalurkan hidrokarbon menuju struktur terapung lainnya. FSO pada masa operasi akan mengalami gerakan akibat respon beban lingkungan, maka FSO memerlukan sistem tambat agar tetap stabil. Sistem tambat Single Point Mooring (SPM) dengan Catenary Anchor Leg Mooring (CALM) digunakan untuk menjaga stabilitas FSO terhadap beban lingkungan. Beban lingkungan yang berulang akan mengakibatkan kelelahan (fatigue) pada struktur. Struktur akan mengalami korosi yang menyebabkan penurunan minimum breaking load (MBL) serta akan mengurangi umur kelelahan (fatigue life). Dalam penelitian tugas akhir ini akan dilakukan analisis pengaruh laju korosi sebesar 5%, 10%, 15%, dan 20% dari diameter asli chain terhadap umur kelelahan rantai tali tambat pada SPM menggunakan metode Pendekatan Combined Spectrum dengan pendekatan Kurva T-N. Dengan mengetahui kondisi terapung bebas dan melakukan simulasi dinamis, akan didapatkan nilai standar deviasi tertinggi pada mooring line dari beberapa load case. Standar deviasi akan digunakan dalam menghitung kelelahan menggunakan metode Pendekatan Combined Spectrum, sehingga akan mendapatkan umur kelelahan dari rantai tali tambat. Hasil analisis menunjukkan bahwa load case yang mengalami standar deviasi tertinggi, yaitu Lightload Inline (LL-IL) dengan nilai standar deviasi 145.59 kN. Hasil perhitungan umur kelelahan menunjukkan pengaruh laju korosi pada umur kelelahan bersifat eksponensial. Pada penelitian tugas akhir ini didapatkan persamaan y = 200.26e-0.335x untuk memprediksi umur fatigue life dan y = 66.752e-0.335x untuk memprediksi umur fatigue life dengan safety factor 3, dengan masing koefisien determinasi R² = 0.9989.
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Floating Storage and Offloading (FSO) is a floating structure that functions to receive, store, and transfer hydrocarbons to other floating structures. During its operation, the FSO is subjected to movements due to environmental load responses, hence requiring a mooring system to maintain its stability. The Single Point Mooring (SPM) system with a Catenary Anchor Leg Mooring (CALM) configuration is used to ensure the stability of the FSO against environmental loads responses. Repeated environmental loading can lead to fatigue on the structure. Additionally, the structure is susceptible to corrosion, which reduces the Minimum Breaking Load (MBL) and consequently decreases the fatigue life. This final project analyzes the effect of corrosion rates of 5%, 10%, 15%, and 20% of the original chain diameter on the fatigue life of the mooring chain in the SPM system using the Combined Spectrum Approach with the T-N Curve method. By identifying the free-floating condition and performing dynamic simulations, the highest standard deviation value of the mooring line from several load cases can be determined. This standard deviation is then used in the fatigue life calculation using the Combined Spectrum Approach to estimate the fatigue life of the mooring chain. The analysis results indicate that the load case with the highest standard deviation is Lightload Inline (LL-IL), with a standard deviation value of 145.59 kN. The fatigue life calculation results show that the influence of corrosion rate on fatigue life is exponential. This study yields the predictive equation y = 200.26e-0.335x for estimating fatigue life and y = 66.752e-0.335x for fatigue life with a safety factor of 3, with respective determination coefficients R² = 0.9989.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Single Point Mooring, Rantai Tali Tambat, Laju Korosi, Umur Kelelahan, Pendekatan Combined Spectrum, Single Point Mooring, Mooring Chain, Corrosion Rate, Fatigue Life, Combined Spectrum Approach
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions:	Faculty of Marine Technology (MARTECH) > Offshore Engineering > 54040-(S1) Undergraduate Thesis
Depositing User:	I Gede Adhi Paramartha
Date Deposited:	25 Jul 2025 07:11
Last Modified:	25 Jul 2025 07:11
URI:	http://repository.its.ac.id/id/eprint/121498

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