Tension Leg Platform Design Optimization for Vortex Induced Vibration

Tension Leg Platform design is a challenging and popular area of research in the offshore oil industry. In order to compete in the International Student Offshore Design Competition (ISODC), a Tension Leg Platform (TLP) was designed. Our TLP design addresses five fundamental areas of technical competency (General Arrangement and Overall Hull/System Design, Weight, Buoyancy and Stability, Global Loading, General Strength and Structural Design, Risk Assessment) and three specialized areas of technical competency unique to a Vortex Induced Vibration (VIV) optimized design (Hydrodynamics of Motions and Loading, Fatigue Strength, and Structural Analysis: global and local strength). Our design optimization process begins with a fourcaisson, four-pontoon tension leg platform, operating at a depth of 3,000 ft. Hydrostatic and hydrodynamic analysis for design iterations are performed by our own MATLAB script, which calculates the effects of motions due to Vortex Induced Vibration (VIV). Structural analysis addresses fatigue loading from VIV. Our design includes risk-based analysis and conforms to class society rules and regulations. VIV phenomena cause uncontrollable motions of offshore platforms, as well as fatigue damage and failure of components such as cables and risers. The effects of VIV need to be addressed early in the design process to avoid costly platform damage and costly retrofits, such as hydrodynamic strakes for platform tendons.