CAE-based design technology study for optimum arrangement of buoyancy modules in SURF system

Abstract

SURF (Subesa Umbilicals, Risers and Flowlines) systems are used for transportation of electric power and underwater resources such as oil, gas and minerals in ocean. The SURF systems are complex and dangerous offshore system due to long length (more than 2,000m) and heavy weight (more than 100ton). For stable installation and operation of the systems, specific shapes such as steep wave or lazy wave configurations should be made through installation of buoyancy modules in theSURF systems due to fatigue failure, collision and twisting of these systems. The mechanical design, arrangement design and SURF shape design should be verified through the real sea tests. However, these verifications can be done by numerical experiment using computing simulation because the real sea tests are dangerous and difficult. In this study, the arrangement design method of buoyancy modules is developed by using multibody dynamics-based SURF systems analysis technology, the genetic algorithm which is the global optimal design algorithm and software framework which can link the analysis tools and algorithms. Multibody dynamics models for the SURF system are developed by DAFUL-DIMS which is the Korean commercial software for the marine mechanical system analysis. The analysis model consists of the structure of euler-timoshenko beam elements and the marine environment such as current, drag, added mass and buoyancy in each element. The buoy