Analisis Tegangan Lokal Pada Trunnion Saat Proses Upending Struktur Jacket Tiga Kaki Tahap Instalasi

Wijaya, Widyantoro Surya Putra (2025) Analisis Tegangan Lokal Pada Trunnion Saat Proses Upending Struktur Jacket Tiga Kaki Tahap Instalasi. Diploma thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Struktur jacket merupakan salah satu jenis struktur anjungan lepas pantai terpancang yang banyak digunakan dalam kegiatan eksplorasi dan produksi minyak dan gas bumi. Struktur ini umumnya diangkut dalam posisi horizontal dan membutuhkan proses upending untuk menegakkannya ke posisi vertikal saat instalasi di lokasi lepas pantai. Dalam proses ini, sistem rigging dan komponen pendukung seperti crane barge dan trunnion memegang peran penting. Pergerakan crane barge akibat kondisi lingkungan laut juga dapat mempengaruhi distribusi beban dan tegangan selama proses upending.Pada penelitian ini dilakukan analisis tegangan local pada trunnion saat proses upending struktur jacket tiga kaki menggunakan model T- Trunnion. Pemodelan crane barge dilakukan menggunakan software MOSES, sedangkan struktur jacket dimodelkan menggunakan SACS. Selanjutnya, analisis dinamis sistem dilakukan dengan menggunakan OrcaFlex, untuk memperoleh data gerakan kapal seperti surge, sway, heave, roll, pitch, dan yaw selama proses upending. Output dari OrcaFlex menjadi dasar untuk menentukan beban kerja rigging dan input analisis tegangan lokal pada trunnion. Analisis lokal trunnion dilakukan dengan software ANSYS menggunakan metode elemen hingga. Hasil simulasi menunjukkan tegangan maksimum von mises pada trunnion sebesar 82.865 MPa, berada jauh di bawah tegangan ijin material baja S355 yaitu 315 MPa. Nilai tersebut menunjukkan bahwa desain T-Trunnion masih dalam kondisi aman. Hasil analisis juga memperlihatkan bahwa pemilihan konfigurasi rigging dan desain trunnion yang tepat dapat mengurangi konsentrasi tegangan dan meningkatkan efisiensi proses instalasi.
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The jacket structure is one of the most commonly used fixed offshore platform types for supporting oil and gas exploration and production activities. This structure is typically transported in a horizontal position and requires an upending process to be rotated into a vertical position during offshore installation. In this process, the rigging system and supporting components such as the crane barge and trunnion play a crucial role. Movements of the crane barge due to environmental conditions at sea can also affect load distribution and stress during the upending phase.This study analyzes the local stress on the trunnion during the upending process of a three-legged jacket structure, using a T-Trunnion model. The crane barge is modeled using MOSES software, while the jacket structure is modeled using SACS. A dynamic analysis of the system is then performed using OrcaFlex, which provides vessel motion data such as surge, sway, heave, roll, pitch, and yaw during the upending operation. The output from OrcaFlex is used as the basis for determining rigging loads and input for local stress analysis on the trunnion.The local stress analysis on the trunnion is conducted using ANSYS software with the finite element method. Simulation results show that the maximum von Mises stress on the trunnion is 82.865 MPa, well below the allowable stress of S355 steel, which is 315 MPa. This indicates that the T-Trunnion design remains within safe stress limits. The analysis also demonstrates that proper rigging configuration and trunnion design significantly reduce stress concentrations and improve the efficiency of the offshore installation process.

Item Type:	Thesis (Diploma)
Uncontrolled Keywords:	Trunnion, Crane Barge, Upending, Tegangan Lokal, Struktur Jacket.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA347 Finite Element Method T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions:	Faculty of Marine Technology (MARTECH) > Offshore Engineering > 54040-(S1) Undergraduate Thesis
Depositing User:	Widyantoro Surya Putra Wijaya
Date Deposited:	29 Jul 2025 09:01
Last Modified:	29 Jul 2025 09:01
URI:	http://repository.its.ac.id/id/eprint/122886

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