Analisa Keandalan Pipa Terhadap Kelelahan Akibat Pitting Corrosion

Chandra, Dimas Wahyu Arie (2016) Analisa Keandalan Pipa Terhadap Kelelahan Akibat Pitting Corrosion. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Jaringan pipa bawah laut merupakan sarana transportasi yang sangat efisien dan
ekonomis dalam mengalirkan fluida dari satu tempat ke tempat lainnya dengan jarak
yang relatif jauh. Dalam sistem perpipaan bawah laut, salah satu permasalahan utama
yang tidak bisa dihindari adalah korosi. Fenomena ini akan bertambah parah dengan
material gas yang korosif dan waktu operasi pipa yang sudah mencapai 38 tahun. Pada
tugas akhir ini, analisa keandalan pipa terhadap kelelahan yang dilakukan terdiri dari
analisis stress intensity factor (SIF) dari pipelines, perhitungan umur kelelahan pipa
setelah terkorosi, serta analisa keandalan pipa. Berdasarkan hasil perhitungan
tegangan, didapatkan stress intensity factor sebesar 5,88 MPa√m dan masih memenuhi
besarnya nilai fracture toughness sebesar 61,41 MPa√m. Untuk hasil perhitungan
analisa kelelahan berupa umur kelelahan pada setiap titik korosi dengan umur pipa pada
korosi paling dalam yaitu 15 tahun sesuai dengan ketebalan minimum yang diijinkan
DNV RP F101 yaitu 70% dari ketebalan. Sedangkan untuk perhitungan keandalan pipa
didapatkan keandalan pipa sebesar 0,99 yang diperoleh dari hasil percobaan sebanyak
25000 kali. Hal ini menunjukkan bahwa pipa masih bisa beroperasi meskipun telah
melewati batas toleransi yang ditentukan oleh DNV RP F101.
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Underwater Pipeline is an efficient and profitable in terms of transporting fluids from
one place to another in a considerably far distance. In terms of underwater pipeline,
one of the main reasons to exist is corrosion. This risk would get even worse if the
transported fluid properties are corrosive and the pipeline has reached above 38 years
lifespan. In this final project, pipeline reliability analysis will be conducted, including
stress intensity factor (KI) from pipeline, corroded pipeline fatigue lifespan
calculation, and pipeline reliability analysis. Based on the of stress calculation, the
output of SIF amount is 5.88 MPa√m, this number still fulfil the amount of fracture
toughness valued 61.41 MPa√m. The calculation of fatigue analysis produced fatigue
lifespan on every corrosion spot, with the corroded pipeline lifespan calculation
reached only 15 years, according to DNV RP F101 which is 70% from the initial
thickness. Last the pipeline reliability calculation produced pipeline reliability in the
amount of 0.99, which is obtained through 25,000 trial. This value concluded that the
pipeline can still operate although it has passed the limit of tolerance from DNV RP
F101.

Item Type: Thesis (Undergraduate)
Additional Information: RSKe 620.112 6 Cha a
Uncontrolled Keywords: stress intensity factor, kelelahan, pipelines, pitting corrosion, keandalan.
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA418.74 Corrosion and anti-corrosives
T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions: Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User: Mr. Tondo Indra Nyata
Date Deposited: 14 Feb 2018 07:12
Last Modified: 14 Feb 2018 07:12
URI: http://repository.its.ac.id/id/eprint/51268

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