Prakoso, Tyo Dwiki (2019) Analisis Umur Kelelahan Sambungan Bracket Topside Module FPSO Menggunakan Fracture Mechanics. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Salah satu tantangan dalam mendesain struktur FPSO adalah struktur antara topside structure dan hull structure. Struktur tersebut harus mempunyai kekuatan yang cukup akibat beban siklis seperti topside inertia loads dan hull girder bending moment akibat beban gelombang pada kondisi lingkungan dan sea states. Beban siklis tersebut menyebabkan terjadinya kelelahan yang memicu terjadinya fatigue cracking sehingga dapat mempengaruhi production integrity. Penelitian ini dilakukan untuk mengetahui umur kelelahan topside interface structure menggunakan dua pendekatan yaitu metode cumulative fatigue damage untuk menganalisis umur kelelahan akibat inisiai retak dan metode pendekatan fracture mechanics untuk menganalisis perambatan retak dan pengaruh perambatan retak terhadap umur kelelahan topside interface structure. Pemodelan struktur dilakukan dengan pemodelan elemen hingga secara global dan lokal. Dari analisis tegangan global didapatkan lokasi kritis yaitu sambungan TS10 untuk selanjutnya ditinjau dalam analisis tegangan lokal. Hasil tegangan normal (sumbu Z) yaitu 29,489 MPa. Setelah itu nilai tegangan tersebut diaplikasikan pada pemodelan retak untuk menentukan nilai stress intensity factor (SIF), laju perambatan retak, jumlah siklus dan umur kelelahan struktur. Dengan itu didapatkan nilai stress intensity factor (SIF) retak awal dari topside interface structure yaitu 1,469 MPa√m dan laju perambatan retak awal yaitu 2,2E-11 m/cycle. Setelah itu didapatkan jumlah siklus dari retak awal sampai retak kritis yaitu 2,3E+05 cycle. Umur kelelahan topside interface structure menggunakan pendekatan fracture mechanics yaitu 101,028 tahun dengan nilai safety factor adalah 5,05. Sedangkan dengan menggunakan metode SN Cuve didapatkan umur yaitu 151,72 tahun.
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One of the challenges in a FPSO project is to design the structure between the topside structure and the hull structure. The structure should have structural adequacy for the cyclic loads like the inertia loads and the hull girder bending moment induced by the wave load in environmental condition and sea states.The cylic loads cause the fatigue cracking that can affects the production integrity. This research is done to know the fatigue life of topside interface structure using two different approach, which are cumulative fatigue damage to analysis of fatigue crack initiation and fracture mechanics to analysis of fatigue crack propagation and the effect of crack propagation to fatigue life of topside interface structure. Structure modelling using finite element methods in global and local model. From the global structure analysis, it is obtained critical location which is at TS10 joint and next it is reviewed using local structre analysis. The normal stress range (Z axis) is 29,489 MPa.. Afterwards the value of the maximum stress is applied to the crack modelling to determine the value of stress intensity factor (SIF), crack propagation rate, total cycle and fatigue life. With that it is obtained stress intensity factor (SIF) value of initial crack is 1,469 MPa√m and initial crack propagation rate is 2,2E-11 m/cycle m/cycle. Next obtained total cycle of initial crack to critical crack is 2,3E+05 cycle. Fatigue life of topside interface structure using fracture mechanic approach is 101,028 years with safety factor value is 5,05. While using the cummulative fatigue damage methods, the fatigue life is 151,72 years.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | cummulative fatigue damage, fracture mechanics, stress intensity factor, perambatan retak dan topside interface structure. |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) > TA347 Finite Element Method T Technology > TA Engineering (General). Civil engineering (General) > TA460 Metals--Fatigue. T Technology > TA Engineering (General). Civil engineering (General) > TA645 Structural analysis (Engineering) T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture) |
| Divisions: | Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis |
| Depositing User: | Tyo Dwiki Prakoso |
| Date Deposited: | 14 Jun 2024 01:04 |
| Last Modified: | 14 Jun 2024 01:05 |
| URI: | http://repository.its.ac.id/id/eprint/65819 |
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