Numerical study on the dynamic characteristics of a vehicle with a multistage load reduction structure during oblique water entry.

The sustained impact load on vehicle entering the water obliquely at high speed can cause structural damage and complex ballistic characteristics. In this paper, a multi-stage load reduction structure (MLRS) combining aluminum foam and a disk cavitator is designed. A three-dimensional numerical model is established using the CEL method to study the high-speed oblique water entry impact of a vehicle. The validity of the numerical method is then verified. Based on numerical models of the vehicle and the multistage loading reduction structure, this study investigates the dynamic characteristics of the vehicle when entering the water directly and when using a MLRS, under different speed conditions and entry angles. The effects of the MLRS on the impact load and attitude behavior of the vehicle under various parameters are studied. The results show that the impact acceleration becomes more prominent with a higher initial velocity when oblique entry. Additionally, smaller entry angle causes the projectile to experience a more significant deflection in its ballistic trajectory. The MLRS designed in this paper can effectively reduce impact loads and modify the characteristics of cavity evolution and trajectory. Moreover, it has a better load reduction effect at a larger access angle. • The paper titled "Numerical study on the dynamic characteristics of a vehicle with a multistage load reduction structure during oblique water entry" contains those highlights: • In this study, a multistage load reduction structure (MLRS) is proposed, comprising a cone cavitator, aluminum foam, and a stretchable bar. • This study investigates the behavior of a vehicle entering water with the MLRS, focusing on the impact loads and trajectory characteristics under various entry velocities and angles. • The designed MLRS demonstrates effective reduction of impact loads and improvement in trajectory stability, particularly in cases involving large angles and high speeds. [ABSTRACT FROM AUTHOR]