Analisis Local Buckling Pada Riser Elbow Akibat Internal Overpressure

Nisa', Sinta Khoirun (2025) Analisis Local Buckling Pada Riser Elbow Akibat Internal Overpressure. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Riser elbow merupakan salah satu komponen penting dalam mendesain riser. Riser elbow berisiko tinggi mengalami kegagalan struktur berupa bursting,buckling,maupun kelelahan yang salah satunya dipengaruhi oleh adanya internal overpressure. Pada Tugas Akhir ini, dilakukan analisis local buckling pada riser elbow akibat internal verpressure.Tahapan pertama ialah menghitung batas tekanan internal yang mengakibatkan tegangan hoop melebihi tegangan yang diijinkan berdasarkan codess ASME B31.8 Gas Transmission and Distribution Piping System, yang didapatkan nilai tekanan internal sebesar 22,40 MPa. Selanjutnya dilanjutkan pemodelan riser elbow pada software Autopipe v.12 untuk local buckling analysis berdasarkan code DNV OS F-101 Submarine Pipeline System, yang didapatkan bahwa untuk setiap variasi tekanan internal riser elbow tidak mengalami local buckling. Namun pada tekanan internal 25,98 MPa dan 26,88 MPa riser elbow berada pada kondisi kritis untuk kriteria pressure containment. Setelah dilakukan analisis local buckling, bagian critical pada riser elbow dimodelkan pada software ANSYS untuk mendapatkan deformasi riser elbow yang diakibatkan oleh internal overpressure. Deformasi untuk setiap tekanan internal 22,40 MPa,24,19 MPa, 25,98 MPa, dan 26,88 MPa berturut – turut bernilai 4,41 mm,4,80 mm,5,19 mm dan 5,38. Nilai tersebut selanjutnya digunakan untuk perhitungan tingkat ovalisasi, berdasarkan codes DNV OS F-101 tingkat ovalisasi riser elbow pada tekanan internal 25,98 MPa dan 26,88 MPa telah melebihi batas aman yakni 0,031 dan 0,032. Sehingga dapat terlihat bahwa tekanan internal sangat berpengaruh terhadap dua kegagalan tersebut, meskipun pada variasi tekanan internal tertentu pipa belum mengalami local buckling, pipa bisa mengalami ovalisasi berlebih.
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Riser elbow is one of the important components in designing a riser. Riser elbow has a high risk of structural failure in the form of bursting, buckling, and fatigue, one of which is influenced by internal overpressure. In this Final Project, an analysis of local buckling in the riser elbow due to internal overpressure is carried out. The first step is to calculate the internal pressure limit that causes the hoop stress to exceed the allowable stress based on the ASME B31.8 Gas Transmission and Distribution Piping System code, which obtained an internal pressure value of 22.40 MPa. Furthermore, continued modeling of the riser elbow in Autopipe v.12 software for local buckling analysis based on the DNV OS F-101 Submarine Pipeline System code, which was found that for each variation of internal pressure the riser elbow did not experience local buckling. However, at internal pressures of 25.98 MPa and 26.88 MPa the riser elbow is in a critical condition for pressure containment criteria. After the local buckling analysis, the critical part of the riser elbow was modeled in ANSYS software to obtain the deformation of the riser elbow caused by internal overpressure. The deformations for each internal pressure of 22.40 MPa, 24.19 MPa, 25.98 MPa, and 26.88 MPa are 4.41 mm, 4.80 mm, 5.19 mm and 5.38, respectively. The value is then used for the calculation of the level of ovalization, based on codes DNV OS F-101 the level of ovalization of the riser elbow at internal pressures of 25.98 MPa and 26.88 MPa has exceeded the safe limit of 0.031 and 0.032. So it can be seen that internal pressure is very influential on these two failures, although at certain internal pressure variations the pipe has not experienced local buckling, the pipe can experience excessive ovalization.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Internal Overpressure, Local Buckling , Ovalization, Riser Elbow, ,Ultimate Limit State,Internal Overpressure, Local Buckling , Ovalization, Riser Elbow,Ultimate Limit State.
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Sinta Khoirun Nisa'
Date Deposited:	15 Jul 2025 06:47
Last Modified:	16 Jul 2025 08:42
URI:	http://repository.its.ac.id/id/eprint/119780

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