Research On Damage Effects Of Ceramic Composite Target Under Impact Of Projectile

Body armor is a special protective clothing which could absorb and dissipate kinetic energy of bullet or fragment,prevent penetration and protect human beings from harming.The evaluation criteria for protective effect of a body armor is the ability of bullet penetration prevention and the ability of preventing non-penetrating trauma.Bullet penetration trauma means injures which caused by the bullets or shell fragments directly hurt human beings'body. Non-penetrating trauma refers to damage to human tissues and organs caused by srtong impact though bullets and fragments are not in direct contact with the human body,those traumas includes skin contusion,parenchyma damage,fracture,internal hemorrhage,aeropleura or emphysema,until the last death.In this paper,we both use experimental investigation and numerical simulation to develop a new type of composite protective structure,and validate the ability of bullet penetration prevention and the ability of preventing non-penetrating trauma.The main contents are as follows:Reference to the third genetation of body armor ,we give a new ceramic-fiber-aluminum protective structure, and validate the ability of bullet penetration prevention,the results show that:in the 150~200m/s speed interval,the protective structure formed by Al2O3 ceramics,basalt fiber,foam aluminum and 2024 aluminum could be effective protection against projectile penetration, and each material in the structure have played an indispensable role in the structure.The protective effect of the structure can be improved by increasing ceramic plate thickness.When the ceramics are under the same total thickness,no matter whether other protective material is added or not,multi-layer ceramic structure are not as good as single-layer ceramic structure in protective effect;and the more of the ceramic layers,the worse its defense capability.Using SHPB we studied dynamic mechanical properties of foam aluminum in different stain rates.we can know that similar to other porous metals,the dynamic process of foam aluminum also have three phases,elastic section,plastic platform section and the compaction section.Because it has a special platform section unlike general metal,it also has a better energy absorption effect than general metal.Compared the stress-strain curves under different strain rates,we found that when the strain rate has a big increment,there's only a small increment of yield stress,so the foam aluminum shows its strain rate insensitive.In ceramic-fiber-aluminum protective structure,we add foam aluminum and use PVDF to measure the ability of preventing non-penetrating trauma.the results show that foam aluminum effective reduce the stress concentration and played a full role in energy absorbing effect,the pressure after structural protection has been harmless to humans.Finally,we studied the anti-penetration capability of ceramic/aluminum composite structure,futher discussed the protective effect of multi-layer ceramic,and validated the results by numerical simulation.The results show that:in the impact experiment of the ceramic/aluminum structure, we obtained the same conclusion, the area of ceramic crush wimble will decrease when ceramics are delaminated,the ceramics absorb less impact kinetic energy,and the protective effect of the whole structure was reduced.The more layers of the ceramics,the smaller area of the ceramic crush wimble,so the worse protective effect of the structure.Another sudy of the formation of ceramic crush wimble by numerical simulation,we can know that its formation is the compression wave and reflect wave result of the role.