Study On Infrared Detection Window Protection Technology

In order to improve the battlefield survivability of armored vehicles and other key equipment,more and more attention has been paid on researching of infrared detection window protection technology in recent years,especially the high-strength transparent protection materials.Because of the characteristics of high hardness,high strength and excellent optical performance,the high strength transparent protection materials are widely used in the fields of armored vehicles,aerospace,etc.,to protect the observation equipments and the crews.According to the requirements of infrared detection window protection and bullet resistance technology,the composite target material made of transparent crystal of alumina(sapphire single crystal),toughened glass and polycarbonate(PC board)is studied The impact resistance of new infrared detection window protection material is mainly studied by theoretical calculation,numerical simulation and range testFirst of all,based on the anti-impact theory of infrared detection window protective material,the the bubble method alumina crystal,flat tempered glass and polycarbonate as the main materials has been selected to compose the target plate.The alumina crystal is set to directly face the projectile,tempered glass as the intermediate protective layer and polycarbonate as the back plate support layer(the total thickness is not more than 30mm),and The ideal penetration depth and broken cone angle caused by 7.62mm Type 53 armor piercing projectile are calculated by using certain assumptions and theoretical formulasThen,ANSYS/AUTODYN software is used to simulate and optimize the structure.A composite material model composed of transparent crystal of alumina,toughened glass and polycarbonate was established.Six kinds of numerical simulation of impact resistance in different order and different thickness ratio of target material were carried out respectively The thickness ratio was 1:1:1,3:2:1,5:3:1,7:3:1,1:5:1,1:2:3,1:3:5,1:3:7.Through comparative analysis,it is found that the order of the three-layer materials is transparent crystal of alumina,toughened glass and polycarbonate,and the composite structure with thickness ratio of 5:3:1 has the best impact resistance.Based on the theory,the impact resistance of the warhead penetrating the target plate at different stages is analyzed with the optimal group,and the mechanism of the crystal breaking and the forming process of the broken cone are analyzedFinally,the impact resistance of the new protective material for infrared detection window is verified.The experimental results are consistent with the theoretical calculation and the computer simulation results.The transparent alumina crystal face plate forms an inverted broken cone under the impact of high overload projectile.The formation of broken cone increases the area of subsequent penetration into the toughened glass face plate and improves the energy absorption effect of the face plate.On the other hand,after the broken cone is formed,the projectile penetrates into the alumina junction in the subsequent penetration,the resistance of the target plate in the process of crystal material is mainly caused by the broken cone.The test shows that the new infrared detection window protection material has excellent impact resistance performance under the condition of the impact of 7.62mm armor piercing projectile(over 700m/s).