Syarif, Hilman (2014) Analisis Kelelahan Akibat Aliran Internal dan Beban Eksternal Pada Pipa Bawah Laut Yang Mengalami Freespan. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Aliran eksternal dan internal fluida dalam pipa yang dapat menyebabkan vibrasi
sehingga berakibat pada kelelahan pada pipa bawah laut telah selesai dianalisis.
Analisis dilakukan dengan mempertimbangkan variasi flowrates aliran internal
fluida serta panjang freespan. Freespan pipa bawah laut yang digunakan dalam
analisis ini adalah yang tidak memenuhi kriteria screening kelelahan menurut DNV
RP F-105. Berdasarkan hasil screening, panjang freespan yang harus dilakukan
analisis kelelahan lebih lanjut adalah freespan dengan panjang 13 meter atau lebih.
Kemudian dipilih tiga freespan yang tidak memenuhi kriteria screening kelelahan,
yaitu freespan dengan panjang 23 meter, 30 meter, dan 36 meter. Selanjutnya
menghitung tegangan pada freespan akibat variasi beban pressure akibat fluida
yang mengalir di dalam pipa dan arus yang mengenai pipa. Pressure tersebut
didapat dari output software CFD. Pada hasil analisis ini didapatkan bahwa
peningkatan flowrates pada inlet berbanding lurus dengan pressure yang dihasilkan
oleh fluida sehingga tegangan yang dihasilkan juga bertambah besar. Semakin besar
tegangan yang dialami freespan, umur kelelahannya akan semakin kecil. Sehingga
bisa disimpulkan semakin besar flowrates semakin kecil umur kelelahan freespan
pipa bawah laut.
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Fluid external and internal flow in the pipeline which can cause vibration resulting
in subsea pipeline fatigue has been completely analyzed. Analysis is done by
considering the variation of fluid internal flow flowrates and freespan length.
Subsea pipeline freespan used in this analysis are those which do not fulfill the
fatigue screening criteria in accordance with DNV RP F-105. Based on screening
result, freespan length that must be done the further analysis are freespan with the
length of 13 meter or more. Then, three freespan which do not fulfill the fatigue
screening criteria are chosen; freespan with the length of 23 meter, 30 meter, and
36 meter. The next step is counting the freespan stress caused by pressure load
variation as a result of fluid flowing in the pipeline and flow hitting the pipeline.
That pressure is obtained from CFD software output. From this analysis result, it is
shown that the enhancement of flowrates at the inlet is directly proportional with
pressure produced by fluid, so that stress produced is bigger. The bigger the stress
experienced by freespan, the smaller the fatigue life. It can be concluded that the
bigger the flowrates, the smaller the fatigue life of subsea pipeline freespan.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 620.112 6 Sya a 3100014056415 |
| Uncontrolled Keywords: | Freespan; aliran internal; aliran eksternal; flowrates; tegangan; umur kelelahan |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines. |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Yeni Anita Gonti |
| Date Deposited: | 23 Dec 2020 03:54 |
| Last Modified: | 23 Dec 2020 03:54 |
| URI: | http://repository.its.ac.id/id/eprint/82338 |
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