Research On The Penetration Resistance Of Polyurea-coated Composite Panels Against K9 Glass Projectiles

When the missile or rocket launching and the aircraft taking off and landing,they facing the threat of rock particles blown by the airflow.Due to the strict weight requirements of aircraft and spacecraft,lightweight materials are the first choice to improve their protective capability.As a new protective material with excellent mechanical properties,polyurea has a broad application prospect.At present,there is no systematic research of the resistance to rock particle’s impact of the polyurea coated composite plate,in this paper,K9 glass as a projectile instead of basalt particles,through the combination of experimental research and numerical simulation,the penetration characteristics of polyurea coated composite plate against rock particle was researched,which revealed the law of deformation-failure rule of polyurea coated composite plate and anti-penetration mechanism.This research provideed reference for the design of aircraft and spacecraft,has important theoretical significance and practical value.Specific research contents and results are as follows:Firstly,the anti-penetration test of polyurea coated composite plate was carried out.Using K9 glass projectile,the penetration test of the composite plate made of different thickness of polyurea coating and different thickness of aluminum alloy board was carried out in two projectile velocity range with light gas gun as launch platform,and the shooting process was photographed with high-speed camera.It was found that the failure modes of projectile include compression at the head and tensile spallation at the tail.The test also showed that the polyurea coating had a good energy absorption effect,which can absorb the projectile kinetic energy through the way of increasing the plastic deformation of the aluminum alloy plate,and the polyurea coating also can reduce the shear failure of aluminum alloy plateSecondly,the anti-penetration simulation of polyurea coated composite plate was carried out.The physical model was established and the appropriate material constitutive model was selected,the rationality and validity of the simulation model were verified by comparing the test results.Based on the test and simulation results,the fragmentation form and mechanical behavior of K9 glass projectile,as well as the anti-penetration mechanism and performance of polyurea coating were further analyzed.It was found that projectile’s peak impact stress and velocity of projectile were related to the thickness of polyurea coating,and the degree and location of fragmentation were related to the size and distribution of peak stress;the unit area density velocity drop of aluminum alloy plate increaseed by about 5% with 1 mm thick polyurea coating,and increaseed by about 40% with 2 mm thick polyurea coating,which can significantly improve the anti-penetration performance of aluminum alloy plate.Thirdly,the anti-penetration characteristics of polyurea coated composite plate was studied.On the basis of the above work,the effects of the speed of projectile and the thickness of polyurea coating in constant areal density on the anti-penetration performance of the composite plate was analyzed with compared of the isoareal density aluminum alloy plates.Under the projectile speed of 400m/s～600m/s,when the thickness of polyurea coating is 1mm or 2mm,the aluminum alloy plate at the back was sheared.Under the projectile speed of 300m/s,when the thickness ratio of polyurea coating to aluminum alloy plate is less than 1/2,the aluminum alloy plate was sheared;when the thickness ratio is more than 2,the aluminum alloy plate was petal cracking failure;when the thickness ratio is about 1,the aluminum alloy plate was tensile necking fracture.When the aluminum alloy plate was sheared or petal cracked,the antipenetration performance of the composite plate was no better than that of the equal area density aluminum alloy plate.When the tensile necking fracture of aluminum alloy plate occurs,the kinetic energy consumption of projectile was large,and the anti-penetration performance of composite plate was significantly higher than that of equal area density aluminum alloy plate.