Tsani, Fitria Sabrina (2023) Analisis Dinamis Tegangan Di Daerah Sagbend Dan Overbend Pada Pipa Akibat Variasi Sudut Stinger Dan Tensioner Tension Saat Proses Instalasi Pipa Bawah Laut Dengan Metode S-Lay. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Pipa bawah laut berperan penting untuk menyalurkan minyak dan gas dari lepas pantai. Salah satu metode instalasi pipa bawah laut yang umum digunakan adalah metode S-lay dimana pipa membentuk kurva "S" selama instalasi. Penelitian ini bertujuan untuk menganalisis pengaruh sudut stinger, tension tensioner, dan arah pembebanan gelombang terhadap tegangan yang terjadi pada pipa selama proses instalasi metode S-lay. Analisis dilakukan pada tiga tahap instalasi, yaitu initiation, normal lay, dan laydown. Hasil analisis menunjukkan bahwa tegangan tertinggi terjadi pada overbend dan sagbend pada tahap normal lay. Tegangan akibat beban dinamis maksimum pada overbend adalah 389,25 MPa, sedangkan pada sagbend adalah 186,80 MPa. Nilai tegangan ini masih memenuhi di bawah batas tegangan kekuatan leleh yang ditetapkan oleh DNV-OS-F101. Sudut stinger terbukti memiliki pengaruh yang signifikan terhadap tegangan von-Mises pada overbend, sementara tension tensioner menjadi faktor dominan pada sagbend. Penurunan sudut stinger sebesar 1° mengakibatkan penurunan tegangan sekitar 0,04%-4,19% pada overbend dan 0,32%-4,38% pada sagbend. Peningkatan tension tensioner sebesar 10 MT menyebabkan penurunan tegangan sekitar 0,09%-2,75% pada overbend dan 0,01%-0,7% pada sagbend. Oleh karena itu, optimalisasi sudut stinger dan tension tensioner menjadi kunci dalam mengontrol tegangan pipa selama instalasi. Analisis dinamis menunjukkan bahwa arah pembebanan gelombang (heading) memiliki pengaruh signifikan terhadap tegangan pipa. Rasio tegangan akibat respon dinamis terhadap statis tergantung pada arah pembebanan gelombang yang berkisar antara 0,97 hingga tertinggi pada heading 90° sebesar 1,42. Disarankan untuk menggunakan sudut stinger di atas 4° dengan tension tensioner antara 30 MT hingga 60 MT untuk memastikan tegangan pipa tetap dalam batas aman. Penggunaan sudut stinger 4° disarankan jika tension tensioner memiliki tegangan di atas 30 MT. Penelitian ini memberikan pemahaman dan rekomendasi praktis untuk mengoptimalkan konfigurasi sudut stinger dan tension tensioner dalam menghindari kegagalan akibat tegangan berlebih.
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Subsea pipelines play a crucial role in offshore oil and gas transportation. One commonly used method for installing subsea pipelines is the S-lay method, where the pipe forms an "S" curve during installation. This study aims to analyze the influence of stinger angle, tension tensioner, and wave loading direction on the stress experienced by the pipeline during S-lay installation. The analysis was conducted in three installation stages: initiation, normal lay, and laydown. The results showed that the highest stress occurred in the overbend and sagbend during the normal lay stage. The maximum dynamic stress in the overbend was 389.25 MPa, while in the sagbend, it was 186.80 MPa. These stress values remained below the allowable yield strength limit set by DNV-OS-F101. The stinger angle was found to have a significant influence on the von-Mises stress in the overbend, while the tension tensioner was dominant in the sagbend. A 1 degree decrease in the stinger angle resulted in stress reduction ranging from 0.04% to 4.19% in the overbend and from 0.32% to 4.38% in the sagbend. Increasing the tension tensioner by 10 MT led to stress reductions ranging from 0.09% to 2.75% in the overbend and from 0.01% to 0.7% in the sagbend. Therefore, optimizing the stinger angle and tension tensioner is crucial for controlling pipeline stress during installation. Dynamic analysis revealed that wave loading direction (heading) had a significant impact on pipeline stress. The stress ratio due to dynamic response to static stress varied between 0.97 and reached its highest value of 1.42 at a heading of 90°. It is recommended to use a stinger angle above 4° with a tension tensioner between 30 MT and 60 MT to ensure the pipeline stress remains within safe limits. The use of a 4° stinger angle is advised if the tension tensioner has a stress above 30 MT. This research provides insights and practical recommendations for optimizing the stinger angle and tension tensioner configuration to prevent failures caused by excessive stress.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | S-lay, Max Von Mises Stress, Stinger, Tensioner, Overbend, Sagbend |
| 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: | FITRIA SABRINA TSANI |
| Date Deposited: | 24 Jul 2023 02:53 |
| Last Modified: | 24 Jul 2023 02:53 |
| URI: | http://repository.its.ac.id/id/eprint/99035 |
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