Study On Collision Performance Of Semi-submersible Living Support Platform Under Mooring State

Semi-submersible life support platform is an auxiliary platform serving drilling platform,which has been in a complex and harsh marine environment for a long time.The berthing state of support platform and drilling platform refers to the dynamic intermediate process in which the platform moves closer to the production platform under its own dynamic positioning or mooring assistance.At this time,the support platform is not ready,the gangway also do not connect to the drilling platform,the mooring system of the support platform itself and the connection cable between the support platform and the drilling platform are in the process of dynamic adjustment.In the state of mooring following,the support platform will collide with the drilling platform due to the environmental loads such as wind,wave and current,operation errors or the failure of the positioning system.This paper on the basic theory of collision accident analysis for digestion,absorption,and then analyze the internal and external mechanism of collision with the method of nonlinear finite element analysis,the research analyzes the life support platform in the presence of semi-submersible mooring condition and tender,drilling platform collision characteristics after collision,the impacting energy dissipation and plastic deformation energy absorption structure and structure such as collision resistance related to the general law.The specific research work is as follows:(1)The applicability analysis and the basic theory of collision accident of semi-submersible life support platform under collision accident are summarized.According to the relevant normative documents and the statistics of historical accidents of shipPlatform Collision and shuttle tanker-FPSO collision,the more dangerous collision parameters(impact speed,impact angle,impact location,etc.)are determined,and the typical working conditions of ship-platform and platform-platform collision are established.(2)The structural damage,energy dissipation and transformation of the pillar structure of semi-submersible life support platform and supply ship without mooring under typical collision conditions are studied by using nonlinear finite element method.On this basis,the sensitivity of different impact parameters such as impact velocity,impact position and impact Angle is analyzed;(3)To have a semi-submersible mooring system support platform for a study of collision characteristic,the analysis by impact load in supporting the structural response of the platform,the motion response and energy dissipation and transformation,and mooringand collision characteristics of semi-submersible platform to carry out the contrast analysis,studies the analysis of characteristics of mooring system for platform collision impact;(4)The relative motion process(speed,depth or impact force)of the supporting platform and the drilling platform,the structural damage of the platform in the collision area,as well as the dissipation and conversion of energy were analyzed,and the impact of collision parameters on the collision characteristics of the platform was also analyzed.This paper has certain guiding significance for the research on the impact of the mooring system on the collision results in the process of ship-platform and platform-platform collision.