Lomantoro, Nonnia Dewi Permata (2018) Analisis Ultimate Limit State Pada Pipa Bawah Laut Yang Mengalami Freespan. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Pipa bawah laut adalah salah satu cara untuk mendistribusikan fluida hasil pengeboran yang mempunyai umur operasi yang relatif panjang dengan biaya operasional dan perawatan yang rendah meskipun biaya pembangunan awalnya relatif mahal. Kondisi seabed yang tidak rata menyebaban pipa mengalami freespan. Pipa dalam kondisi operasional harus mampu menahan gaya dari dalam pipa itu sendiri (internal load) dan gaya dari luar pipa (eksternal load). Kegagalan pada pipa sering terjadi karena beban yang terjadi pada pipa melebihi batas aman
kekuatan materialnya. Cara untuk mengetahui batas maksimal kekuatan pipa bawah laut adalah dengan memeriksa kekuatan maksimalnya dengan cara menganalisis menggunakan pendekatan Ultimate Limit State (ULS). Kriteria analisis ULS telah diatur pada codes DNV RP F105: Free Spanning Pipelines 2006, sedangkan kriteria yang lebih detail dijelaskan pada codes DNV OS F101: Submarine Pipeline System 2013. Hasil panjang maksimal setelah screening frekuensi natural adalah 7 meter. Sedangkan panjang maksimal span kondisi ULS 7.5 meter. Kedua panjang span
maksimal tersebut tidak menghasilkan tegangan ekuivalen melebihi tegangan buckling kritis. Sehingga dapat ditarik kesimpulan apabila panjang freespan maksimal yang diizinkan adalah 7 meter. Analisis tegangan ekuivalen
menggunakan software menghasilkan tegangan ekuivalen yang mendekati perhitungan manualnya dengan error sebesar 3%.
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Subsea pipeline is one way to distribute drilling fluids that has a relatively long service life with low operational and maintenance costs even though the initial construction costs are relatively expensive. The uneven seabed condition causes the freespan. Pipes under operational conditions should be able to withstand forces from within the pipe itself (internal load) and force from outside the pipe (external load). Pipe failure often occurs because the load on the pipe exceeds the safe limit of material strength. The way to find out the maximum limit of subsea pipeline strength is to check its maximum strength by analyzing it using the Ultimate Limit State (ULS) approach. The ULS analysis criteria have been set in the DNV RP F105 codes: Free Spanning Pipelines 2006, with the more detailed criteria are described on the DNV OS F101 codes: Submarine Pipeline System 2013. The maximum result after the natural frequency screening is 7 meters. While the maximum length of the span condition of ULS 7.5 meters. The two maximum length spans do not produce the equivalent stress over the critical buckling stress. So it can be deduced if the maximum freespan length allowed is 7 meters. The equivalent stress analysis using the software produces an equivalent stress approaching the manual counting with an error of 3%.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 621.867 2 Lom a-1 |
| Uncontrolled Keywords: | Subsea pipeline, freespan, ULS, local buckling, DNV. |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures T Technology > TJ Mechanical engineering and machinery > TJ935 Pipe--Fluid dynamics. Tubes--Fluid dynamics |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Nonnia Dewi Permata Lomantoro |
| Date Deposited: | 16 Jun 2021 06:30 |
| Last Modified: | 16 Jun 2021 06:30 |
| URI: | http://repository.its.ac.id/id/eprint/54097 |
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