Research On The Protective Performance Of Ti/Al₃Ti/metal Composite Aarmor Based On The Material Point Method

The protective performance of military armor is directly related to the battlefield viability of various military equipment.Ti/Al₃Ti composite is very suitable for military protective armor because of its excellent properties such as high strength,high modulus,high stiffness,low density and high fracture toughness.At present,scientists at home and abroad mostly apply the finite element method to study the properties of Ti/Al₃Ti composites.However,the process of projectile penetrating Ti/Al₃Ti composites belongs to the problem of large deformation,which often produces mesh distortion and affects the calculation accuracy and efficiency.As a kind of object grid method,material point method can effectively avoid grid distortion.The research shows that the metal back plate material can provide support for Ti/Al₃Ti composite and improve its overall protective performance.However,there is little research on Ti/Al₃Ti/metal composite armor at home and abroad.Therefore,the factors affecting the protective performance of Ti/Al₃Ti/metal composite armor is studied based on the material point method in this paper.The material point method program of projectile penetrating Ti/Al₃Ti/metal composite armor has been written in Fortran90 language.The process of projectile penetrating Ti/Al₃Ti composite materials have been simulated by the program.The simulation results are consistent with the experimental results in the literature,which verifies the feasibility of the material point method program.The effects of various structural parameters of Ti/Al₃Ti/metal composite armor（the type of metal back plate,the arrangement order of composite armor,the area density of panel material Ti/Al₃Ti,the area density of metal back plate material,the Ti volume fraction of panel material Ti/Al₃Ti,and the total number of layers of panel material Ti/Al₃Ti）on the protective performance of Ti/Al₃Ti/metal composite armor were studied based on the material point method.The results show that the protective performance and ballistic limit of Ti/Al₃Ti/AZ31 magnesium alloy composite armor are significantly better than Ti/Al₃Ti/4340 steel composite armor and Ti/Al₃Ti/6061 aluminum alloy composite armor under the same surface density.The protective performance of Ti/Al₃Ti/metal composite armor with metal material as back plate is better than that of Ti/Al₃Ti/metal composite armor with metal material as front plate.The increase of surface density of Ti/Al₃Ti panel and metal back plate can significantly improve the protective performance of Ti/Al₃Ti/metal composite armor.But with the increase of surface density of Ti/Al₃Ti composite and metal back plate,the specific energy absorption of Ti/Al₃Ti/metal composite armor will not continue to increase.The increase of the number of layers and Ti volume fraction of Ti/Al₃Ti composites can also improve the protective performance of Ti/Al₃Ti/metal composite armor,but the effect is not obvious.In order to study the primary and secondary laws of structural parameters affecting the protective performance of Ti/Al₃Ti/metal composite armor,an orthogonal test scheme was designed by taking the specific energy absorption as the test index and the surface density of panel material Ti/Al₃Ti,the surface density of metal back plate material and the type of metal back plate as the test factors.Through range analysis,it is found that when the surface density of the panel is 1.93g/cm²,the surface density of the back plate is 1.44g/cm²and the metal is AZ31 magnesium alloy,the specific energy absorption of Ti/Al₃Ti/metal composite armor is the highest.Through the analysis of variance,the primary and secondary order of the influence of structural parameters on the protective performance of Ti/Al₃Ti/metal composite armor under the test conditions is as follows:the type of metal back plate>the area density of metal back plate material>the area density of panel material Ti/Al₃Ti.The research results in this paper have certain guiding significance for the design of Ti/Al₃Ti/metal composite armor,and also provide a novel method and idea for the research of simulating projectile penetration into composite armor.