Research On Vibration Isolation Technology Of Offshore Platform Of Steel Sea Jacket

Jacket platform,the major form of ocean engineering structures,vibrates violently under action of sea ice load to influence the stability of structure and undermine reliability of the platform,thereby threatening the body and mind security of operators.Therefore,the research on vibration isolation technology for ocean platform has great practical application value.Based on actual engineering projects,the steel jacket platform on certain tidal of the Bohai Sea is taken as object for research to analyze the dynamic characteristics of jacket platform structure and dynamic response under ice induced load by combining theoretical investigation and numerical simulation.Then the vibration isolation technology is studied.Major research contents include:(1)Research on fundamental theory of ice induction.The physical mechanical characteristics of sea ice and ice induced vibration mode of ocean platform are analyzed,and calculating mode of ice force suitable for fixed structure in the Bohai Sea is researched.(2)The vibration of jacket platform under ice-induced load is analyzed.The structural performance and dynamic characteristics of steel jacket ocean platform for certain tidal is researched based on numerical simulation method to establish a finite element calculation model,and the first ten-order modality for the platform is analyzed and calculated,thereby obtaining the modal parameters of inherent frequency,maximum displacement and node for the platform under each order of modality.Based on this,the ice induced vibration value is calculated and analyzed for the platform,finding the response displacement of maximum displacement for the platform under specific condition is up to 20cm.The sea ice has a large influence on the researched jacket platform,so appropriate measures must be taken to isolate the vibration.(3)The vibration isolation technology of jacket platform structure is researched:the mechanical model for vibration isolation cone is established;vibration isolation cone is designed,with laminated rubber boot as the major component.The size of laminated rubber is defined according to above research to lower the ice induced vibration response.Numerical simulation method is adopted to calculate and analyze ice induced vibration for platform arranged with vibration isolation cone.This study shows that compared with the simulation result of ice induced vibration for original jacket platform,the maximal displacement on the platform after vibration isolation is 4.8cm,a significant decrease,indicating general satisfactory effect of vibration isolation.