Study On Dynamic Response And Residual Strength Of Hull Structure Under The Action Of Air Explosion Load

Floating Production Storage and Offloading is an important facility used for offshore oilfield development.FPSO combines crude oil production,storage and offloading functions in one,which has the characteristics of high integration,high technical requirements and great difficulty in construction.The FPSO outboard structure and its oil transfer risers are special and important structures,and collisions are likely to result in structural damage,casualties and environmental pollution.The FPSO outboard structure and its oil transfer risers are special and important structures and collisions are likely to cause structural damage and oil and gas leakage.Therefore,it is very important to study the mechanical characteristics of FPSO side and riser structures under collision loads,new forms of protection structures and the collision resistance of FPSO with composite functional gradient materials.This thesis summarizes the research on the collision mechanics of ships at home and abroad,and uses a combination of theoretical analysis and numerical simulation to study the influence of typical impacting ships on the mechanical properties of FPSO under the action of different collision positions,velocities and angles and other key factors,and to analyse the dynamic response law of typical FPSO structures and outboard riser structures under the action of collision loads.On the basis of this,a new type of protection structure for the FPSO side and riser is studied,and an optimisation scheme for the protection structure is proposed;and based on the relevant material test results,a numerical simulation intrinsic model of composite functional gradient material is established,and a new type of composite functional gradient material protection scheme for the FPSO under collision load is studied.The main contents of this thesis are as follows:(1)Numerical simulation and theoretical study of ship collision.The non-linear finite element theory and key technologies involved in the numerical simulation of ship collision are summarized systematically;the control method of time step of explicit integration,the intrinsic model of material in the collision response process are introduced,and the contact algorithm and friction algorithm in the collision process are compared and analyzed;the numerical simulation method of reinforced plate collision process is studied,and the numerical simulation results are compared with the relevant literature,so as to verify the reliability of the numerical The numerical simulation results are compared with relevant literature to verify the reliability of the numerical simulation;the classical laminate theory of composite materials in the collision process of ships is discussed in depth.(2)Study of the mechanical properties of typical FPSO structures under collision loads.The mechanical characteristics of the collision between a typical impacting ship and an FPSO under different angles,speeds and collision positions are investigated,and the mechanical characteristics of the damage deformation,collision force and energy absorption of the FPSO under different angles,speeds and collision positions are analysed.The study of the dynamic response of the outboard riser structure under the action of collision loads and the comparison of the riser impact depth with the DNV code to obtain the speed range of the impacting ship under the permissible damage to the riser,providing reference for the subsequent study of the collision mechanical characteristics of the FPSO.(3)Research on new FPSO protection structures under collision loads.Based on the mechanism of FPSO structural protection under collision loads,three new FPSO fender structures were designed,and the stress distribution characteristics,collision forces and energy absorption characteristics of FPSO collision areas under three fender schemes were studied to obtain a new fender structure protection scheme with better collision resistance;seven new types of riser protection structures were proposed,and the stress distribution characteristics,collision forces and energy absorption characteristics of FPSO collision areas under different schemes were analysed to obtain a new fender structure protection scheme with better collision resistance.The new protection structure of the riser is a new type of protection structure with better collision resistance.(4)Study of the mechanical characteristics of the FPSO composite functional gradient material protection structure under collision loading.In this thesis,four different composite functional gradient material solutions are designed and numerical simulations are used to study the damage deformation,collision forces and energy absorption characteristics of the rib reinforcement structure and riser structure on the side of the FPSO under composite functional gradient materials,to obtain the energy absorption effect of the four functional gradient materials and to propose a new composite functional gradient material solution with strong collision resistance and good energy absorption effect.