Studi Parametrik Analisis Kelelahan Tali Tambat pada Spread Mooring FSO

Cahyaningtyas, Dewinta Putri (2023) Studi Parametrik Analisis Kelelahan Tali Tambat pada Spread Mooring FSO. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Tesis ini menyajikan studi parametrik umur kelelahan yang diterapkan pada FSO (Floating Storage and Offloading) yang ditambatkan dengan sistem spread mooring. Beberapa kasus parametrik dirancang untuk menginvestigasi pengaruh sudut mooring dan pre-tension pada umur kelelahan spread mooring. Objek pada penelitian ini adalah FSO dengan konfigurasi spread mooring yang dioperasikan di kedalaman air 30 meter. Sistem tambat terdiri dari 8 catenary mooring line yang disusun dalam 4 kelompok dengan masing-masing 2 mooring line. Simulasi domain waktu diterapkan untuk menghitung respons dinamis dan tegangan mooring lines. Fatigue life dinilai dengan menggunakan metode rainflow counting (perhitungan curah hujan), kurva T-N dan hukum Palmgren-Miner. Untuk kasus konfigurasi sudut mooring, sistem tambat dengan sudut mooring 30 dan 60 menghasilkan umur kelelahan yang paling lama dibandingkan konfigurasi sudut simetris 45 serta sudut 45 dan 90. Hasil analisis pre-tension menunjukkan bahwa studi kasus dengan pre-tension yang lebih tinggi menghasilkan umur kelelahan tali tambat yang lebih pendek. Pre-tension secara signifikan berpengaruh terhadap umur kelelahan tali tambat dibandingkan dengan mooring angle, baik pada Splash Zone, Mid-Catenary Zone, serta Touchdown Zone. Hal ini dibuktikan dengan nilai p-value pre-tension yang jauh lebih kecil dibandingkan dengan nilai p-value sudut mooring.
Kata kunci : Fatigue Life, Mooring Angle, Pre-Tension, Rainflow Counting, Spread Mooring.
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This thesis presents a parametric study of fatigue life applied to FSO (Floating Storage and Offloading) moored with a spread mooring system. Several parametric cases were designed to investigate the effect of mooring angle and pre-tension on the fatigue life of mooring spreads. The object of this study is an FSO with a spread mooring configuration which is operated in a water depth of 30 meters. The mooring system consists of 8 catenary mooring lines arranged in 4 groups with 2 mooring lines each. Time domain simulation is applied to calculate the dynamic response and voltage of the mooring lines. Fatigue life was assessed using the rainflow counting method, the T-N curve and the Palmgren-Miner law. In the case of the mooring angle configuration, the mooring system with mooring angles of 30 and 60 produces the longest fatigue life compared to the symmetrical configuration of 45 and angles 45 and 90. The results of the pre-tension analysis show that case studies with higher pre-tension produce fatigue life shorter mooring ropes. Pre-tension significantly affects the fatigue life of the mooring lines compared to the mooring angle, both in the Splash Zone, Mid-Catenary Zone, and the Touchdown Zone. This is evidenced by the p-value of pre-tension which is much smaller than the p-value of the mooring angle.
Keyword : Fatigue Life, Mooring Angle, Pre-Tension, Rainflow Counting, Spread Mooring.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Fatigue Life, Mooring Angle, Pre-Tension, Rainflow Counting, Spread Mooring, Umur Kelelahan, Sudut Tambatan, Tegangan Awal, Perhitungan Curah Hujan, Sistem Tambat Menyebar
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures V Naval Science > VK > VK361 Mooring of ships. Dry docks
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38101-(S2) Master Thesis
Depositing User:	Dewinta Putri Cahyaningtyas
Date Deposited:	18 Jan 2024 03:41
Last Modified:	18 Jan 2024 03:41
URI:	http://repository.its.ac.id/id/eprint/102237

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