Numerical Simulation Research On Impact Resistance Of Offshore Platform Free-fall-lifeboat

As the last line of defense for offshore drilling,platform self-rescue and escape equipment plays an indispensable role in protecting the life and property safety of platform personnel.As a kind of self-help escape equipment,free-fall-lifeboat will have a high-speed water entry impact with seawater when it is released from the hull frame.In the process of water entry impact,a huge and complex fluid impact load will be generated,the impact load not only damage the hull structure and equipment in the boat,but also threaten the personal safety of the crew in the boat.Therefore,the effective numerical calculation of free-fall-lifeboat into the water impact problem,through the analysis of the numerical simulation results,then optimize the design of the hull structure,can effectively reduce the accident caused by the hull structure strength is not enough,to better protect the life and property of the crew in the boat is of great significance.First of all,this paper briefly reviews the domestic and foreign research progress of the structural water entry impact problem from three methods of theoretical research,experimental research and numerical simulation,analyzes and summarizes the advantages and disadvantages of each method and the scope of application,and briefly introduces the research progress of the water entry impact problem of free-fall-lifeboat.In this paper,the numerical simulation method is used as the primary method to study the water entry impact of free-fall-lifeboat.Based on the large-scale dynamic analysis software LS-DYNA and ALE algorithm,the numerical simulation of the water entry impact of free-fall-lifeboat is carried out,which points out the direction for the research methods and technical support of this paper,and lays the foundation for the follow-up work.Secondly,this paper numerically simulates the vertical water entry process of the hemispherical structure model,and takes the experimental results as the benchmark,and compares and analyzes the simulation results.The results show that the acceleration simulation results of the hemispherical structure are in good agreement with the experimental results,which verifies the effectiveness of the LS-DYNA software used in this paper to study the water entry impact of free-fall-lifeboat.In order to solve the problem of water entry impact of free-fall-lifeboat,this paper establishes the finite element model of the lifeboat and the fluid domain by setting the grid element type,material and initial boundary conditions of lifeboat,the air domain and the sea area,and divides them into grids,and then establishes the numerical model of water entry impact of free-fall-lifeboat.In the process of lifeboat and fluid domain modeling and meshing,the necessary model simplification and meshing are carried out according to the principle of geometric model simplification and meshing requirements.Then,in this paper,the numerical simulation calculation is carried out for the water entry stage of free-fall-lifeboat in the water entry impact process under typical working conditions,and the response characteristics of free-fall-lifeboat in the water entry impact under this working condition are explored,and the integrity of the hull structure and the acceleration overload of the crew at different parts of the seat are emphatically observed.The simulation results show that the bow area of the hull structure is subjected to a large impact load during the impact of free-fall-lifeboat into the water,but the integrity of the hull structure is not damaged;the occupants in the middle and stern seats of the hull are subjected to the maximum acceleration overload during this process,and although this overload does not exceed the ultimate acceleration overload that ordinary people can withstand,in order to make the acceleration overload of the crew of the hull as small as possible,this paper still puts forward some seat shock resistance improvement measures.Finally,the numerical simulation of the water entry impact of the elastic body model and the rigid body model of free-fall-lifeboat is compared and analyzed.The results show that the calculation time of the rigid body model is shorter if only the speed is considered,but the calculation results of the elastic body model are more accurate when other factors are considered.At the same time,this paper also discusses the influence of initial water entry angle and water entry speed on the impact response of free-fall-lifeboat...