Pratama, Wiradhani (2015) Analisis Umur Kelelahan Struktur Catenary Anchored Leg Mooring Buoy Pada Single Point Mooring FSO Arco Ardjuna Saat Kondisi Tertambat. Undergraduate thesis, Institut Technology Sepuluh Nopember.
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Abstract
Dalam tugas akhir ini akan dilakukan analisa umur kelelahan struktur catenary
anchored leg mooring buoy pada single point mooring FSO Arco Ardjuna saat
kondisi tertambat. Analisa ini dilakukan karena masa pengoperasian FSO Arco
Ardjuna akan diperpanjang, oleh karena itu perlu dilakukan analisis umur
kelelahan struktur SPM yang dimana merupakan salahsatu fungsi mooring pada
FSO Arco Ardjuna. Dengan mengetahui perilaku gerak antara FSO Arco Ardjuna
dan Single Point Mooring akibat beban lingkungan perairan pada kondisi
tertambat, akan didapatkan nilai tension pada anchor legs dan hawser dari
beberapa konfigurasi pembebanan. Selain itu, akan diketahui nilai tekanan
hidrostatis dan akselerasi pada struktur Single Point Mooring sebagai input dalam
analisis tegangan struktur global. Setelah itu dilakukan analisa tegangan global
struktur Single Point Mooring dengan beban tension pada anchor legs dan
hawser, selain itu juga beban tekanan hidrostatis, akselerasi struktur dan beban
berat keseluruhan struktur itu sendiri. Dari hasil tegangan global, dilakukan
perhitungan umur kelelahan struktur SPM dengan menggunakan metode S-N
Curve berdasarkan hukum kegagalan Palmgren Miner dengan mengestimasi
kumulatif kegagalan fatigue menggunakan metode simplified. Dari hasil
pemodelan numerik yang dilakukan, diketahui bahwa perilaku gerak terbesar pada
FSO Arco Ardjuna yaitu sebesar 1.104 deg/m untuk gerakan roll saat kondisi light
load dan 3.968 deg/m untuk gerakan heave pada SPM saat tertambat dengan FSO
Arco Ardjuna kondisi full load. Untuk hasil tension pada anchor legs terbesar
yaitu 571.51 kN pada anchor leg1 pada arah 00 dengan safety factor 12.34,
dimana hasil ini memenuhi syarat yang dianjurkan oleh ABS yaitu 1.67.
Sedangkan hasil tension pada hawser terbesar yaitu 997.07 kN pada hawser 2
pada arah 00 dengan safety factor 4.11, dimana hasil ini masih memenuhi syarat
yang dianjurkan oleh ABS yaitu 1.82. Setelah itu, didapatkan tegangan
maksimum pada struktur SPM sebesar 137.16 MPa dan deformasi sebesar 5.6
mm. Hasil ini masih lebih kecil jika dibandingkan dengan tegangan ijin dan
deformasi yang dianjurkan oleh ABS yaitu 225 MPa dan 11.2 mm. Berdasarkan
tegangan maksimum tersebut, diperoleh hasil umur kelelahan konstruksi bolder
yaitu 68 tahun selama umur operasi.
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In this paper, fatigue life that occur in catenary anchred leg mooring buoy
structure on single point mooring FSO Arco Ardjuna due to the influence of
mooring condition. This analyzing due to operation life of FSO Arco Ardjuna
becomes longer, so it is important to do fatigue analysis for Single Point Mooring
that became one of moring function of FSO Arco Ardjuna. This case study begins
with motion analysis of FSO and Single Point Mooring due to the environment
load in mooring condition, then the tension of anchor legs and hawser will be
found due to mooring condition . In addition, it will be known the hydrostatic
pressure and structure acceleration of Single Point Mooring that used for input of
global stress analysis. Based of tension of anchor legs and hawser, and so
hydrostatic pressure, structure acceleration and structure’s self weight, global
stress analysis of Single Point Mooring structure will be done. From the results of
the global stress, the calculation will be known for the fatigue life analysis of SPM
structure by using S-N curve method based of Palmgren Miner’s rules with
estimate the cumulative fatigue damage using the method of simplified. Based on
the modeling, it is known that the dominant motion for FSO Arco Ardjuna is 1.104
deg/m in roll at light condition and 3.968 deg/m in heave for SPM that moored
with full load condition of FSO Arco Ardjuna. Based on the simulation carried
out to obtain the maximum tension, the maximum anchor leg tension obtained on
the anchor leg 1 is 571.51 kN at heading 00 and the safety factor is 12.34. That
safety factor was requires by ABS, which is 1.67. And the maximum hawser
tension obtained on the hawser 2 is 997.07 kN at heading 00 and the safety factor
is 4.11. That safety factor was requires too by ABS, which is 1.82. While, the
global stress analysis of SPM structure with maximum stress of 137.16 MPa and
maximum deformation of 5.6 mm. This stress and deformation is less than the
allowable maximum stress required by ABS, 225 MPa and 11.2 mm. based on the
maximum stress, obtained the result of fatigue life in bolder construction is 68
years as long as the operation.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 627.22 Pra a |
| Uncontrolled Keywords: | hot-spot stress, maximum principal stress, simplified fatigue assessment, single point mooring |
| Subjects: | 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: | 22 Nov 2019 08:06 |
| Last Modified: | 22 Nov 2019 08:06 |
| URI: | http://repository.its.ac.id/id/eprint/71989 |
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