Design And Analysis Of The Leg Buffer For Vertical Take-off And Landing Reusable Launch Vehicle

How to reduce the cost of space launch is one of the major challenges facing the world's space powers.The reusable launch vehicle recovers the rocket in different ways,and realizes the reuse of some hardware after maintenance,which greatly reduces the launch cost of the rocket and simplifies the ground supporting equipment,and has extremely high military and civilian value.Therefore,it is of great significance to study the landing buffer device of reusable launch vehicle for improving the recovery level of China's space vehicles and enhancing national defense strength.The effects of horizontal velocity,landing attitude angle,ground friction coefficient and roll angle velocity on landing cushioning characteristics of reusable launch vehicle during soft landing are analyzed;the effects of stiffness and damping of the leg damper on the landing cushioning characteristics are explored,and the stiffness and damping of the damper are optimized.The comprehensive extreme conditions under the combination of various influencing factors are found out,and the buffer index requirements are determined according to the comprehensive extreme conditions of rocket landing.The maximum energy that can be absorbed by a single leg buffer is determined,and three buffering schemes are proposed according to the buffer index requirements.Then,the advantages and disadvantages of honeycomb buffer and thin-walled metal tube plastic deformation buffer are analyzed,and the two-stage honeycomb buffer is adopted.Finally,the configuration of leg buffer is determined and the parameters of honeycomb buffer are optimized based on the objective of minimizing mass and volume.The finite element model of honeycomb is established based on LS-DYNA,and the effects of mesh element size and impact speed on the buffering characteristics of honeycomb are analyzed.The simulation analysis of the honeycomb buffer is carried out to explore the deformation characteristics and buffer characteristics of the honeycomb crushing process.The experimental study on the energy absorption characteristics of the leg buffer is carried out experimentally.The experimental results verify the accuracy and feasibility of the honeycomb finite element model.Finally,based on the energy absorption characteristics of the leg buffer,landing process of the reusable launch vehicle was simulated and verified.