Analisis Kekuatan Struktur Jacket Platform Tipe Empat Kaki Akibat Tubrukan dengan Supply Vessel

Sulthana, Zaidan Arsa (2026) Analisis Kekuatan Struktur Jacket Platform Tipe Empat Kaki Akibat Tubrukan dengan Supply Vessel. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Operasi logistik di sekitar fixed jacket platform lepas pantai menimbulkan risiko tubrukan kapal yang mengancam integritas struktur. Penelitian ini menganalisis dampak tubrukan supply vessel SV. Prospero 9 (554 ton) terhadap kekuatan CAT Platform empat kaki pada variasi kecepatan 0,5 m/s, 1 m/s, dan 2 m/s. Analisis dilakukan menggunakan software SACS untuk respons global dan ANSYS LS-DYNA untuk analisis lokal pada jacket leg. Perhitungan standar API RP 2A-WSD menghasilkan energi bow impact sebesar 76,175; 304,7; dan 1.218,8 kN.m, serta energi broadside impact sebesar 96,95; 387,8; dan 1.551,2 kN.m. Analisis in-place menunjukkan struktur sebelum tabrakan sangat aman (UC 0,36). Pascatubrukan skenario bow, jacket leg mulai gagal (FAIL) pada kecepatan 1 m/s (UC 1,274) hingga mencapai UC 5,397 pada 2 m/s. Skenario broadside lebih destruktif bagi komponen pengaku (brace) yang langsung FAIL sejak kecepatan 0,5 m/s (UC 1,074) hingga UC 22,895 pada 2 m/s. Simulasi lokal pada kondisi kritis (bow 2 m/s) menunjukkan konsentrasi tegangan elasto-plastis maksimum. Maksimum material ASTM A36 melebihi nilai ultimate strength dan mencapai nilai konvergen Peak Von Mises Stress sebesar 1216 MPa. Kondisi ini memicu kegagalan bentuk permanen (local dent) pada dinding pipa kaki jacket dengan kedalaman penyok maksimal mencapai 34,5 cm pada node 7325.
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Logistical operations around offshore fixed-jacket platforms pose a risk of vessel collisions that threaten the structural integrity of the platform. This study analyzes the impact of a collision involving the supply vessel SV Prospero 9 (554 metric tons) on the strength of a four-leg CAT platform at speeds of 0.5 m/s, 1 m/s, and 2 m/s. The analysis was performed using SACS software for global response analysis and ANSYS LS-DYNA for local finite element analysis of the jacket legs. Standard API RP 2A-WSD calculations yielded bow impact energies of 76.175, 304.7, and 1,218.8 kN·m, and broadside impact energies of 96.95, 387.8, and 1,551.2 kN·m. In-place analysis indicates that the structure was highly safe prior to the collision (UC 0.36). Following the bow collision scenario, the jacket leg began to fail (FAIL) at a speed of 1 m/s (UC 1.274), reaching a UC of 5.397 at 2 m/s. The broadside scenario was more destructive to the bracing components, which failed immediately starting at a speed of 0.5 m/s (UC 1.074) to UC 22.895 at 2 m/s. Local simulation under critical conditions (bow 2 m/s) shows the maximum elasto-plastic stress concentration. The maximum stress in the ASTM A36 material exceeded the ultimate strength and reached a convergent peak von Mises stress value of 1216 MPa. These conditions triggered permanent deformation (local dent) in the jacket leg pipe wall, with a maximum dent depth of 34.5 cm at node 7325.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Jacket Collision,Finite Element Analysis,Speed Variation
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:	Zaidan Arsa Sulthana
Date Deposited:	28 Jul 2026 02:47
Last Modified:	28 Jul 2026 02:47
URI:	http://repository.its.ac.id/id/eprint/138449

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