Investigation Of Failure Modes Of Water Tank Subjected To The Impact Of Projectiles

With the rapid development of the economy,the ocean has gradually become the focus of national protection and development.As an important strategic resource,marine resources may cause some naval battles,which not only damage the equipment on the ship,but also seriously threaten the lives and property of the staff.The naval vessels,fuel tanks and tank protection structures of underwater vehicles may be damaged by explosion loads and fragments,so it is of significance to study the damage mechanism of tank structures.With the introduction and popularization of the concept of lightweight ship structure in recent years,5A06 aluminum has a wide range of advantages in marine engineering and shipbuilding due to its good corrosion resistance,high strength,good weldability and cutting performance.It is widely used in marine engineering and shipbuilding industry.In this paper,5A06 aluminum panel was selected as the front and rear target panels of the tank.The combination of experimental and numerical simulation was used to study the failure of the panels under the impact of projectiles.Specific contents are listed as follows:(1)The laboratory-scaled penetration experiments were carried out,the water inlet attitude of the projectile and the evolution of the cavity caused by the impact of the projectile were recorded by the high-speed camera.The velocity decay of the projectiles with three different nose shapes in the water-filled tank and the size of cavity generated by the impact were compared,which can illustrate the dissipation of the kinetic energy of the projectile.(2)The failure modes of the panels under the impact of projectiles were qualitatively summarized at the different initial velocity,and the failure mechanism of the panels were compared and analyzed from the nose shape of the projectile.The effects of the nose shape of the projectiles,the initial velocity of the projectile,and the thickness of the panels on the ultimate deformation of the postmortem panels were further analyzed.In addition,the dynamic response of the front and rear targets of the tank was obtained by strain gauges attached to the panels.The effect of hydrodynamic ram on the deformation of the front and rear target panels was analyzed.Finally,the failure mechanism of the target panel was further verified by scanning electron microscope(SEM).(3)The finite element software ANSYS/LS-DYNA was used to simulate the penetration process of the tank,and the validity of the finite element model was verified by comparison with experiments.Then,the simulating of flat projectiles impact tanks at different velocities were carried out.The initial peak of shock wave,the velocity attenuation of the projectile,and the size of the cavity were compared and analyzed.In addition,the approximate linear relationship between the maximum deformation of the panels and the velocity of the projectile was established.Combined with the experimental and numerical results,the critical value between different failure modes of the target panels is determined,and the failure modes map of the target panels is established.(4)Simulation of the working conditions which flat projectiles impacting tanks with different water contents was carried out.The influence of water content on the velocity decay of the projectiles was analyzed.The process of the penetration under different water content was analyzed from the energy point of view.In addition,the influence of water content on the dynamic stress-strain response and displacement response of the target panels were analyzed.Finally,the influence of water content on the deformation of the target panels under the impact of the projectile was analyzed and obtained.