Analysis On Ice-induced Vibration Of Offshore Jacket Platform Based On DEM-FEM

Jacket offshore platforms are affected by environmental loads such as wind, wave current and ice during their service process. In ice covered regions, ice load is dominated load for jacket offshore platform. Jacket offshore platform is a frame structure which made of steel, Jacket offshore platform have good mechanical property. The structure of flat ice is an infinite plane shell. Sea ice is very prone to bending or buckling failure when extruded jacket platform leg by wind, waves, and current.Ice-induced vibration of Jacket offshore platform is detected through on-site monitoring in Bohai jacket platform. Sea ice with high velocity, strength and thickness will cause strong ice-induced vibration in Jacket offshore platform. Ice-induced vibration serious threat to the oil and gas production equipment on the jacket platform, likely to cause fatigue damage to the platform structure. The acceleration on the jacket platform caused by ice-induced vibration serious damage to the health of workers.Different structure form and size of jacket platform has a significant impact on the dynamic ice load. This paper summarizes the structural features of jacket platform, analyzes the structure forms and size requirements of strut, pile and deck of the jacket platform in detail. Taking JZ20-MUQ in Liaodong Bay of Bohai as an example, we reasonablely simplified structure and created a finite element model of the jacket platform in this paper.In recent years, discrete element method (DEM) of sea ice made a good development, it can accurately simulate sea ice disappearance, migration, fracture process. The study of the sea ice crushing process needs to transition from continuum mechanics to discrete mechanics when sea ice interactive with jacket platform. Having a bond-broken features of sea ice discrete element method can be a good simulation of the mechanical behavior of this process. We applied DEM of sea ice calculate ice load time history in jacket platform in this paper.Finite element analysis(FEA) in solid theoretical basises, fast and efficient features. Finite element analysis becomes necessary and effective means of engineering structure design and analysis with the popularity of commercial software like ANSYS etc. We analysized ice-induced vibration on jacket platform by ANSYS finite element analysis software. Besides, we analyzed the impacts of different ice ice-induced vibration parameters on the platform combine the DEM of sea ice and the FEA of structure, through which we concluded the general formula of the acceleration by using ice parameter to estimate the ice-induced vibration of the platform.