Research On Vibration Control Of Self-centering Offshore Platform

The result of the rapid growth of the global economy is huge consumption ofenergy, currently, the world’s onshore hydrocarbon resources is increasingly drying up,in the future people will focus on the development of the ocean, which is contain vastmineral resources. The offshore platform as the basic facility for the development ofmarine oil and gas resources, working in a evil condition, that may lead to seriousaccidents to the offshore platform, it has important theoretical and practical significanceto take reasonable and effective structural vibration control technology in order to avoidaccidents and improve the service life and security of the offshore platform. At presentstructural vibration control technology has a larger development in many fields,especially in the construction, aerospace, mechanical and civil engineering remarkableresults have been achieved.This paper puts forward two structural forms of self-centering offshore platform,one offshore platform structure is based on the self-centering rocking wall, the otherself-centering offshore platform structure is based on prestressed cables, study thedynamic response of two forms of the offshore platform structure through makingsimulation analysis. The main research content of this paper have:(1) Using the finite element analysis software ANSYS to model the originalstructure, making simulation analysis to the offshore platform structure under differentearthquake loads and ice loads, then using ANSYS to establish three-dimensional modelof the offshore platform structure which is based on the self-centering rocking wall andcalculate the natural frequencies and corresponding vibration mode. Analysis resultsshow that increasing the rocking wall’s stiffness and buoyancy have good vibrationdamping effect both, and stiffness of the self-centering rocking wall is the maininfluencing factors. After several simulation analysis, this paper finally selected50times stiffness ratio of the self-centering rocking wall and floating box can providingmaximum buoyancy0.5G as the best condition.(2) Prestressed cables are used in offshore platform, using the finite elementanalysis software ANSYS to model the whole structure and calculate the natural frequencies and vibration mode of the self-centering offshore platform structure, thenmaking dynamic response analysis to the offshore platform structure under differentearthquake loads and ice loads, and calculate the influence of prestress and arrangementof prestressed cables on the platform nodes’ maximum displacement and maximumacceleration. The results show that value of prestress and arrangement of inhaul cablescan effectively reduce the dynamic response of offshore platform, have a better controleffect and robustness.