Study On Design And Dynamic Response Of The Blast Wall For A Sea Launch-Recovery Ship

Since the successful completion of the first launch of the Long March 11 launch vehicle in China’s Yellow Sea waters in June 2019,China’s sea launch rocket program has begun to develop a comprehensive layout.Yantai Haiyang production base began the construction of a new type of sea launch recovery vessel at the Eastern Spaceport in October 2021,for the explosive impact load of liquid rocket launch propellant,the ship blast wall structure has become an important part of the ship design and development.In this study,the selection and structural design of the blast wall were completed with reference to the blast wall structural design specification for the explosion impact scenario of the rocket launch recovery at sea,and the structural response of the blast wall under the blast load and rocket debris penetration was investigated using numerical simulation methods.The main research contents and conclusions are as follows:(1)The design value of the shock load was determined by equating the TNT equivalent to the liquid launch vehicle and calculating the overpressure peak based on the physical characteristics of the blast shock wave.The numerical simulation of TNT explosion in infinite air domain was carried out using the fluid-solid coupling(ALE)method,and the overpressure load was verified by comparing the reflection and bypassing ability of shock wave blocked by curved,flat and slotted plates with different angles,and the general arrangement of slotted blast wall was determined.Based on the calculated impact loads,the design of the blast wall crosssection with reinforced panels was completed with reference to the internationally accepted blast wall design codes.(2)Referring to the explosion impact test of blast wall published by the authoritative organization Health and Safety Executive(HSE),through the comparison of numerical simulation and test response,the verification of structural nonlinear finite element dynamic analysis modeling method was carried out,and the dynamic response assessment of blast wall under the action of explosion impact load was completed.Based on this method,the explosion impact load was simulated by Conwep algorithm in launch and first-stage recovery conditions,and the explosion response on the launch and recovery ship was simulated numerically.The material of blast wall is C-S constitutive,with failure strain and maximum deformation as evaluation criteria.The calculation results indicate that the designed blast wall can withstand the impact load of the rocket during launch and recovery.(3)The THOR equation is used to determine the convergence of the model and to validate the structural response of the numerical simulations.The debris penetration model is analysed for different inclination angles and initial velocities.The results show that the blast wall with reinforcement can effectively block the penetration of debris,and the penetration speed of debris is related to the incidence velocity and inclination angle of debris.The penetration velocity of debris is related to the incident velocity and inclination of debris.When the incident velocity of debris is certain,the larger the incident inclination is,the more velocity will be lost and the smaller the penetration velocity will be,even the phenomenon of "bounce" will occur.On this basis,several fragments with "0" penetration velocity are designed to provide reference for the design of structural intrusion prevention and rapid evaluation of the intrusion effect.