Fatigue Design and Analysis of Lazy-S Riser in Natuna Sea

• Main Author: Surti Rumingkang (nim : 15513014), Nitis
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23516
• Institution: Institut Teknologi Bandung

Riser is defined as the vertical or near-vertical segment of pipe connecting the facilities above water to the subsea pipeline. Riser will exposed by cyclic hydrodynamics loadings such as wave and current. These loads occur repeatedly and may lead to fatigue failure. Fatigue is one of the design criteria that have to be considered while doing the structure design. In this final project, fatigue life and fatigue damage of Lazy-S Riser in an FPSO that operates in Natuna Sea will be discussed and examined. The study is performed by simulating the FPSO and riser using dynamic analysis software. Fatigue analysis is referring to DNV RP F204 “Riser Fatigue” and DNV RP C203 “Fatigue Design of Steel Structure” and performed based on S-N curve approach. The result obtained shows that the riser’s thickness needs to be increased so that the riser cross-sectional area is reduced by 2.67%. This riser is safe from fatigue failure and the minimum fatigue life is 22.3 years with 4.5% per year fatigue damage.