Analisis Keandalan On-Bottom Stability pada Subsea Pipeline dengan Metode Simulasi Monte Carlo Berbasis Scilab

Imron, Didik Ali (2018) Analisis Keandalan On-Bottom Stability pada Subsea Pipeline dengan Metode Simulasi Monte Carlo Berbasis Scilab. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pipa bawah laut yang di instal pada seabed akan terkena beban hidrodinamis berupa arus maupun gelombang yang dapat menyebabkan struktur pipa mengalami pergeseran kearah vertikal maupun lateral. Interaksi antara beban hidrodinamis, seabed dan pipa itu sendiri merupakan masalah yang kompleks, lebih dari itu, dengan adanya ketidakpastian statistika pada komponen tersebut membuat pekerjaan pipeline menjadi semakin rumit. DNV RP-F109 memberikan kriteria desain untuk mencegah perpindahan pipa secara berlebihan sebagai Serviceability Limit State (SLS) yang mengakomodasi ketidakpastian menggunakan safety factor (kriteria LRFD). Pada penelitian ini, ketidakpastian pada komponen perhitungan on-bottom stability (OBS) juga di analisis menggunakan metode probabilistik. Simulasi Monte Carlo digunakan dalam prosesnya dengan bantuan program berbasis Scilab. Dalam kasus ini, hasil analisis menunjukkan bahwa metode DNV RP-F109 memberikan estimasi pipe-requirement weight yang lebih konservatif dibandingkan metode probabilistik. Selain itu, hasil analisis keandalan pada sloping seabed menunjukkan fenomena bahwa keandalan on-bottom pipeline stability akan mengalami peningkatan seiring dengan meningkatnya sudut kemiringan seabed, untuk kondisi upslope instability. Sementara itu pada kondisi downslope instability, keandalan akan semakin menurun seiring meningkatnya sudut kemiringan seabed. ============== Subsea pipeline installed at seabed will experience the wave and current loads which potentialy tend to destabilize the pipeline both vertically and horizontally. The interaction between hydrodynamic loads, seabed and pipeline itself is a complex problem. Moreover, with uncertainties in its component making the pipeline work even more complicated. The design of subsea pipeline against excessive displacements (DNV RP-F109) is defined as a Serviceability Limit State (SLS) which accomodated the uncertainty with a safety factor (LRFD criterion). In this research, uncertainties in On-Bottom Stability components was analyzed using probabilistic method too. Monte Carlo Simulation used at its process with Scilab-based assistance program. In this case, analysis results show that DNV RP-F109 give more conservative estimation at pipe-requirement weight than probabilistic method. Moreover, analysis results of pipeline reliability at sloping seabed show that the reliability of On-Bottom Pipeline Stability will increase with the increasing of seabed angle, for upslope instability condition. Meanwhile, at downslope instability condition, the reliability will decrease with the increasing of seabed angle.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: DNV RP-F109, Monte Carlo Simulation, On-bottom Pipeline Stability, Probabilistic, Reliability, Scilab, Sloping Seabed
Subjects: T Technology > T Technology (General) > T174.5 Technology--Risk assessment.
T Technology > T Technology (General) > T55 Industrial Safety
T Technology > T Technology (General) > T57.5 Data Processing
T Technology > TC Hydraulic engineering. Ocean engineering > TC1665 Offshore structures--Materials.
T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
T Technology > TN Mining engineering. Metallurgy > TN879.5 Petroleum pipelines
Divisions: Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User: Didik Ali Imron
Date Deposited: 08 Feb 2019 08:56
Last Modified: 08 Feb 2019 08:56
URI: http://repository.its.ac.id/id/eprint/53672

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