| Individual protective armor is a type of individual protective equipment with multiple functions such as bulletproof,anti-stabbing,and fire prevention.At present,it plays an increasingly important role in localized and small-scale wars.Although traditional protective armor can provide good protection performance,it basically does not have the ability to deform,which greatly limits the soldiers to perform necessary tactical actions and operations.Therefore,designing a new type of protective armor considering functionality,flexibility and economy has become a key research direction of modern national defense technol ogy.The development of individual protective armor is of great significance to improve individual combat capability of soldiers.Based on bionic research,it can provide new ideas for the design of high-performance armor.The shell of the armadillo consists of hexagonal scales which are tightly joined together.It adopts a layered structure design,which has good flexibility and protection ability.This paper is based on bionic mechanism and combined with the relevant research results of composite material s,in order to design a flexible composite ballistic plate with good protective performance and flexibility,which enhance the fitness when worn,and improve the soldier’s combat ability.This paper can also provide a reference for the design and optimizat ion of new types of ballistic plate in the future.In this paper,the primary contents of this research is summarized as follows:(1)Drawing on the ideas of bionics,a new structural form of ballistic plate with geometrical arrangement of hexagonal scales was designed by studying the geometric arrangement pattern and double-layer structure of the armadillo shell scales.By comparing the performance of different protective materials,it is determined that the hard layer and soft layer were simulated with the Si C ceramic and ultra-high-molecular-weight polyethylene(UHMWPE)hot-compressed plate,respectively.Meanwhile,the relevant dimensional parameters of bionic scale were determined.The side length of a single scale is 12 mm and the thickness is 10 mm.The thickness ratio of the Si C layer to the UHMWPE layer is 1:1.Finally,the theoretical geometric model of flexible ballistic plate was designed.(2)Finite element model(FEM)of a flexible composite ballistic plate was established.According to the protection level II of national military standard"Requirements of safety technical performance for military body armor"(GJB4300A-2012),the 7.62 mm lead-core bullet and the 7.62 mm steel-core bullet were used to perform the FEM of ballistic penetration.The results show that the ballistic plate can effectively resist the penetration of the two bullets,and verify that it has the protection level II of GJB 4300A-2012.Meanwhile,according to the simulation results,the destruction characteristics of the ballistic plate are analyzed:including three-stage destruction process of the ballistic plate,stress distribution,synergy of scales,displacement of the ballistic plate,and limit protection speed.The simulation analysis of the penetration effect of the fragments specified in GJB 4300A-2012 on the ballistic plate shows that it has better protection performance against the fragments.(3)By using the established FEM as a reference,test specimens of composite scales and flexible ballistic plate were prepared,and a complete preparation method and process were summarized.According to the protection level II of GJB4300A-2012,ballistic performance test of ballistic plate was conducted.The results show that the ballistic plate successfully resisted the penetration of 7.62 mm lead-core bullet and 7.62 mm steel-core bullet respectively,and verify that the accuracy of the finite element simulation analysis.Ballistic performance test proves that the ballistic plate has protection level II of GJB 4300A-2012.At the same time,a flexible testing of ballistic plate was conducted by using the MTS universal testing machine.When the load reached 50 N,the vertical displacement of the ballistic plate was about 11mm,which indicates the ballistic plate has good bending and deformation capabilities.(4)The FEM of flexible composite ballistic plate is established to optimize the area density of the ballistic plate.It is set that the area density gradient of five groups of ballistic plate.By adjusting and optimizing composite scale thickness,scale double-layer thickness ratio and number of backing layer,the smallest area density of ballistic plate that meet the protection level II of GJB 4300A-2012 is 18 kg/m~2.The optimal combination scheme of ballistic plate is 3 mm for the composite scale Si C layer,2 mm for the UHMWPE layer,and 40 for backing layer.The results of the optimization give full play to the performance of the protective material,reduce the weight of the ballistic plate,and are more in line with the requirements of light weight and high efficiency of the new type of ballistic plate. |
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