Structure Design For A Offshore Integrated Test Platform

The development and utilization of fossil fuel cause a sharp reduction in resources and the increasingly serious environmental problems.Vigorously developing renewable energy has become a trend and got widely accepted.Among the renewable energy,offshore wind energy,tidal energy and solar energy are gradually getting attention,relevant test of power plant is carried out orderly.Offshore integrated test platform of this paper provide the floating foundation for the test of the sea wind power generator,tidal generator and photovoltaic power generation.As the platform for the conceptual design only,lacking the necessary structural design,so the main research content of this paper is that based on the ABS rules,complete the structure design and strength checking of yield,buckling and fatigue of the platform.Referring to the ABS MODU specification of marine mobile offshore drilling unit(MODU),design the plate thickness and the size of stiffeners of the float,column,bar,the upper shell and the lower body.Then,according to the specification and the related calculation theory,calculate the environment load(including wind load,current load and the wave load).Using HydroD hydrodynamic analysis module of SESAM software,wave load computation of the platform is finished.Wave load calculation is based on the design wave method,which through calculating the transfer function of the first order wave force.Using Genie structure finite element analysis in SESAM software to analysis the structural response of Offshore integrated test platform under survival condition,the equivalent stress nephogram is concluded and node stress is extracted.Reference to yield failure criterion to accomplish the overall and local yield strength check.Then,according to the ABS MODU construction and classification rules,check the buckling strength,such as central horizontal pole structure and deck plate of the platform.Finally,using the the deterministic fatigue analysis method based-on S-N curve to analysis the fatigue intensity of the fatigue hot nodes.The papers selecting three modes of sea state from China sea waves scatter diagram,and define wave heighht and period of the design wave as three load cases.According to ABS Guide for the Fatigue Assessment of Offshore Structures,select the appropriate S-N curve,utilize SESAM software to accomplish fatigue analysis and fatigue life prediction of two fatigue hotspots.Eventually the results meet the design fatigue life of 25 years.