Analisis Keandalan Pipeline akibat Tegangan saat Instalasi Metode S-Lay dengan Variasi Kedalaman dan Pre-Tension pada Tensioner

Manalu, Sela Nurcahaya Aprilia (2025) Analisis Keandalan Pipeline akibat Tegangan saat Instalasi Metode S-Lay dengan Variasi Kedalaman dan Pre-Tension pada Tensioner. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pipa bawah laut adalah alat transportasi yang berperan penting dalam memenuhi penyediaan kebutuhan minyak dan gas. Sebelum dioperasikan, pipa bawah laut harus diinstal terlebih dahulu. Dalam tugas akhir ini, telah dilakukan analisis keandalan terhadap struktur pipa bawah laut saat proses instalasi dengan menggunakan metode S-lay dengan pengaruh variasi dari kedalaman lokasi instalasi dan besar tension pada tensioner. Data pipa yang digunakan dalam analisis ini merupakan pipa standar API 5L Grade X65 dengan batas SMYS 450 MPa. Analisis keandalan dilakukan dengan melihat kriteria tegangan berdasarkan DNVGL ST F101. Tegangan von mises yang didapatkan dari analisis dinamis menjadi moda kegagalan untuk mengetahui keandalan dari struktur pipa bawah laut pada kondisi instalasi. Hasil analisis menunjukkan bahwa tegangan von mises pada overbend lebih tinggi dibandingkan pada sagbend. Dengan kenaikan kedalaman dari 30, 35, 40, hingga 42 m, kecenderungan tegangan von mises juga mengalami kenaikan baik di daerah overbend maupun sagbend. Sedangkan, untuk pengaruh dari besar tension pada tensioner memberikan pengaruh yang berbeda-beda di setiap kedalaman. Untuk kedalaman 30 m dan 35 m, kenaikan tension cenderung menurunkan tegangan von mises secara signifikan pada bagian sagbend saja. Pada kedalaman 40 dan 42 m, kondisi tension yang semakin besar secara signifikan akan menurunkan tegangan von mises baik pada overbend maupun sagbend. Berdasarkan hasil analisis allowable stress dan keandalan, terlihat bahwa faktor kedalaman dan tension pada tensioner memiliki pengaruh terhadap tegangan von mises pada pipeline yang sedang diinstal. Disarankan untuk kedalaman 30 m dan 35 m, digunakan tension 392 kN. Sedangkan untuk kedalaman 40 m dan 42 m disarankan menggunakan tension 492 kN. Penelitian ini memberikan pemahaman dan rekomendasi praktis untuk mengoptimalkan variasi antara faktor kedalaman dan tension pada tensioner dalam menghindari kegagalan akibat tegangan von mises berlebih.
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Subsea pipeline are a means of transportation that plays an important role in meeting the supply of oil and gas needs. Before being operated, subsea pipelines must be installed first. In this final project, a reliability analysis has been carried out on the structure of the subsea pipeline during the installation process using the S-lay method with the influence of variations in the depth of the installation location and the amount of tension on the tensioner. The pipe data used in this analysis is a standard API 5L Grade X65 pipe with an SMYS limit of 450 MPa. Reliability analysis is carried out by looking at the stress criteria based on DNVGL ST F101. The von Mises stress obtained from the dynamic analysis becomes a failure mode to determine the reliability of the subsea pipeline structure under installation conditions. The results of the analysis show that von Mises' stress on the overbend is higher than on the sagbend. With an increase in depth from 30, 35, 40, to 42 m, the tendency of von Mises stress also increases both in the overbend and sagbend areas. Meanwhile, the amount of tension on the tensioner has different effects at each depth. For depths of 30 m and 35 m, increasing tension tends to reduce von Mises significantly stress in the sagbend section only. At depths of 40 and 42 m, the increasing tension condition will significantly reduce von Mises stress in both overbend and sagbend. Based on the results of the allowable stress and reliability analysis, it can be seen that the depth and tension factors on the tensioner have an effect on the von Mises stress in the pipeline being installed. It is recommended to use a tension of 392 kN for depths of 30 m and 35 m. For depths of 40 m and 42 m, it is recommended to use a tension of 492 kN. This study provides an understanding and practical recommendations for optimizing the variation between the depth and tension factors on the tensioner in avoiding failure due to excessive von Mises stress.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Pipa bawah laut, Instalasi, Tegangan, Keandalan, Subsea Pipeline, Installation, Stress, Reliability.
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines. V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM161 Ships--Hydrodynamics
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Sela Nurcahaya Aprilia Manalu
Date Deposited:	22 Jan 2025 02:12
Last Modified:	22 Jan 2025 02:12
URI:	http://repository.its.ac.id/id/eprint/116499

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