Composite enhanced boron carbide bulletproof plate and preparation method thereof

Abstract

The invention relates to the technical field of bulletproof plates, in particular to a composite enhanced boron carbide bulletproof plate and a preparation method thereof.The composite enhanced boron carbide bulletproof plate comprises a honeycomb body, the honeycomb body comprises a base plate and a honeycomb grid, and ceramic matrixes are arranged in meshes of the honeycomb grid; ultra-high molecular weight polyethylene is filled between the ceramic base body and the inner walls of the meshes, a fiber back plate is arranged on the back face of the honeycomb body, a damping layer is arranged on the bullet facing face, the fiber back plate, the honeycomb body and the damping layer are connected into a whole through an adhesive, and an edge covering layer is wrapped outside the fiber back plate, the honeycomb body and the damping layer. A cushion layer formed by an ultra-high molecular weight polyethylene material is used for powerfully supporting a ceramic matrix, sufficient fragmentation and energy absorption of a ceramic material are facilitated, meanwhile, a small honeycomb grid is used for limiting fragmented ceramic cones in the honeycomb grid, energy absorption is fully completed, impact force of bullets is dispersed and transmitted to the whole honeycomb body, and therefore the back concave depth is reduced, and the service life of the honeycomb body is prolonged. Point impact is transferred into surface impact, and the blunt injury probability of a user is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bulletproof plates, and in particular to a composite reinforced boron carbide bulletproof plate and a preparation method thereof. Background Art

[0002] With the update and upgrade of new weapons, the initial velocity and penetration of bullets have also increased accordingly. The development of automated weapons has made it more common for multiple bullets to hit at the same time. Therefore, the bulletproof performance against the impact of multiple bullets has received more and more attention. Generally, in order to improve the bullet penetration performance, bulletproof plates are usually made of ceramic materials, metal materials and ultra-high molecular weight polyethylene materials. However, ceramic materials are hard and brittle materials. When penetrated by bullets, the radial cracks formed in the ceramic materials are very easy to expand to the entire ceramic plate surface. The broken pieces of ceramics cannot be fixed in the bulletproof plate and flow, thereby weakening the ceramic material, which is not conducive to the bulletproof plate's performance against multiple bullets.

[0003] In the prior art, in order to reduce the crack expansion of ceramic materials, reduce the performance weakening of ceramic materials, and improve the performance of bullet-proof panels against multiple bullet strikes, smaller ceramic blocks are usually used for splicing, and artificial cracks are used to block the range of crack expansion of the entire ceramic block. Even if a certain piece of ceramic material is shattered by a bullet, other ceramic materials still have good impact resistance, and the protective performance of other parts of the bullet-proof panel is retained. However, there are certain problems, namely: the connection between ceramic materials and metals, ultra-high molecular weight polyethylene and other materials is not firm, and they are easy to fall off when impacted, especially small pieces of spliced ​​ceramics. Bullet-proof panels are usually curved panels, and small pieces of spliced ​​ceramics are basically planar structures, which cannot maintain good contact on the curved panels, and the impact resistance and energy absorption effect of the connection strength are further reduced.

[0004] On the other hand, there are two bulletproof grade standards that are widely used in China, one is the American standard NIJ 0101.06 standard, and the other is the Chinese GA 141-2010 standard. The NIJ 0101.06 standard is currently the most widely known standard in the world. The NIJ standard has the deepest back concave depth of all standards: no more than 1.73 inches / 44 mm. That is, when the bullet hits the bulletproof plate, the height of the bulge formed on the side close to the body does not exceed 44 mm, which is qualified. Although such a bulletproof plate is qualified, when facing the impact of the bullet, the bulletproof plate will form a bulge of more than 40 mm on the side close to the body within a dozen to dozens of milliseconds, and the user will suffer serious injuries at this time, thus affecting the combat effectiveness.

[0005] Therefore, in addition to being lightweight and high-strength, reducing blunt trauma to the user is also an extremely important performance indicator for bulletproof plates. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a composite reinforced boron carbide bulletproof plate and a preparation method thereof, which reduces the back concave depth and reduces the blunt impact injury of the user while maintaining the light weight and high strength of the bulletproof plate.

[0007] The technical solution adopted in this application to solve this technical problem is:

[0008] A composite reinforced boron carbide bulletproof plate comprises a honeycomb body, wherein the honeycomb body comprises a substrate and a honeycomb grid integrally prepared on the substrate, a ceramic matrix is ​​arranged in the meshes of the honeycomb grid, ultra-high molecular weight polyethylene is filled between the ceramic matrix and the inner wall of the meshes, a fiber back plate is arranged on the back of the honeycomb body, and a damping layer is arranged on the bullet-facing surface, the fiber back plate, the honeycomb body and the damping layer are connected as a whole by an adhesive, and an edge layer is wrapped on the outside.

[0009] The ultra-high molecular weight polyethylene filled between the ceramic matrix and the inner wall of the mesh can provide strong support for the ceramic matrix, so that the ceramic matrix is ​​subjected to balanced force and absorbs more energy when it is shattered by bullet impact, thereby reducing the depth of the back concave.

[0010] Furthermore, the spacing between the ceramic substrate and the inner wall of the honeycomb grid is less than or equal to 1 mm.

[0011] Furthermore, the honeycomb body is made of aluminum alloy, and the side length of the honeycomb grid is 10mm-20mm.

[0012] The smaller meshes of the honeycomb grid can restrain the ceramic matrix, and at the same time restrain the broken ceramic cone when the bullet impacts the ceramic matrix, thereby enhancing the energy absorption effect, reducing the penetration depth of the bullet, and thus reducing the back concave depth.

[0013] Furthermore, the damping layer is a sheet material formed by laminating and bonding multiple layers of Kevlar fiber cloth, and the thickness of the damping layer is 2mm-4mm.

[0014] The damping layer also absorbs energy from the bullet, reducing the impact force of the bullet on the ceramic matrix. After the energy is reduced, the impact force of the bullet is reduced, the impact strength on the ceramic matrix is ​​reduced, and the depth of the back concave is further reduced.

[0015] Furthermore, the fiber backboard is a board body composited by UD cloth and EVA foam material, wherein the thickness of the EVA foam material is greater than the thickness of the UD cloth, and the overall thickness of the fiber backboard is 8mm-10mm.

[0016] The fiber backboard is mainly used to protect the human body. When the bullet dissipates energy, the point impact of the bullet is dispersed by the honeycomb body into a larger surface impact. The EVA foam material on the fiber backboard adheres to the surface of the human body while absorbing the impact energy, increasing the contact area and reducing the impact intensity.

[0017] A method for preparing a composite reinforced boron carbide bulletproof plate, used for preparing the composite reinforced boron carbide bulletproof plate, comprises the following steps:

[0018] Step S1: preparing a honeycomb body, a ceramic matrix, a damping layer and a fiber backplane;

[0019] Step S2: filling the mesh of the honeycomb body obtained in step S1 with ultra-high molecular weight polyethylene particles, then adding the ceramic matrix, placing the honeycomb body in a hot pressing mold and hot pressing the mold on a flat hot pressing machine, removing the excess burrs on the surface of the projectile-facing side after cooling, and then grinding the surface to obtain a basic protective plate;

[0020] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer and the fiber back plate respectively, perform hot pressing in an autoclave, slowly cool down to below 40°C, take out the plate, and wrap it with an edge layer to obtain a bulletproof plate.

[0021] Furthermore, in step S2, the hot pressing temperature is 145°C-150°C, the pressure is 10 MPa, and the hot pressing time is 1.5h-2h. After the hot pressing is completed, the surface of the ceramic substrate is flush with the mesh openings of the honeycomb body.

[0022] Furthermore, in step S3, a 1mm-1.5mm polyurea coating is sprayed on the surface of the plate and then the plate is hemmed with Oxford cloth.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention utilizes ultra-high molecular weight polyethylene material to fill between the ceramic matrix and the base plate to form a sufficient cushion layer, thereby providing strong support for the ceramic matrix, which is beneficial for the ceramic material to fully break and absorb energy. At the same time, a smaller honeycomb grid is utilized to confine the fragments of the ceramic matrix within the honeycomb grid, thereby squeezing the bullet, fully absorbing energy, and dispersing the impact force of the bullet to the entire honeycomb body, thereby reducing the depth of the back concave, transferring the point impact to the surface impact, and reducing the probability of blunt injuries to the user.

[0025] 2. The present invention utilizes a smaller honeycomb structure to limit the ceramic cone of the ceramic matrix from being broken, and at the same time disperses the impact force to the entire honeycomb body, and converts the linear impact of the bullet into an outwardly dispersed expansion and extrusion, thereby reducing the penetration depth of the bullet, so that the present invention can use less material to complete the protection against bullets.

[0026] 3. The present invention also includes a damping layer and a polyurea coating as an edge layer, which can absorb the impact of bullets, provide a certain buffer when the bullet impacts, and increase the energy dissipation of the bullet. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a schematic structural diagram of the composite reinforced boron carbide bulletproof plate of the present invention;

[0028] Figure 2 This is a schematic diagram of the back concave depth measurement.

[0029] The numbers in the attached drawings are: 1, edging layer; 2, damping layer; 3, ceramic matrix; 4, honeycomb body; 5, honeycomb grid; 6, substrate; 7, fiber backboard; 8, UD cloth; 9, EVA foam material. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0031] like Figure 1 As shown, a composite reinforced boron carbide bulletproof plate includes a honeycomb body 4, wherein the honeycomb body 4 includes a substrate 6 and a honeycomb grid 5 integrally prepared on the substrate 6, wherein the mesh opening direction of the honeycomb grid 5 faces the bullet-proof direction, the honeycomb body 4 is made of aluminum alloy by 3D printing, the mesh depth of the honeycomb grid 5 is 10mm-13mm, the side length is 10mm-20mm, or it is formed by directly drilling holes on an aluminum alloy plate with a thickness of 12mm-15mm using a machine tool, and a ceramic matrix 3 is contained in the honeycomb grid 5, and the ceramic matrix 3 matches the honeycomb grid 5, that is, the ceramic matrix 3 is just placed in the honeycomb grid 5, and the distance between the ceramic matrix 3 and the inner wall of the mesh of the honeycomb grid 5 shall not be greater than 1mm, and the ceramic matrix 3 is a boron carbide ceramic material, which has low density and high hardness and is an ideal bulletproof material, and alumina ceramics or silicon carbide ceramics can also be used.

[0032] Since the bulletproof plate is a curved structure, but the material of the ceramic matrix 3 is usually a flat material such as a flat plate or a block material, and because the ceramic matrix used in the present invention is small in size, it is not easy to distinguish even if it is prepared as a curved material. Therefore, the ceramic matrix 3 and the substrate 6 of the honeycomb body 4 are in point contact or line contact, and the substrate 6 cannot provide good support for the ceramic matrix 3, which is not conducive to the ceramic matrix 3 fully breaking and absorbing energy when the bullet hits. Therefore, ultra-high molecular weight polyethylene is used here to fill between the ceramic matrix 3 and the substrate 6. The filling method is to add one or two ultra-high molecular weight polyethylene particles to each mesh in advance. The ultra-high molecular weight polyethylene particles melt and flow at high temperature, and pressure is applied to the ceramic matrix 3 to make the molten ultra-high molecular weight polyethylene flow and fill the gap between the ceramic matrix 3 and the honeycomb grid 5. After filling, the ultra-high molecular weight polyethylene forms a support layer between the ceramic matrix 3 and the honeycomb grid 5. When the bullet hits the bulletproof plate, the boron carbide ceramic can have better support, so that it can absorb more energy when broken.

[0033] The back side (non-bullet-facing side) of the honeycomb body 4 is bonded with a fiber back plate 7, which is a plate body composited by a UD cloth 8 and an EVA foam material 9. Because the ceramic matrix 3 of the present invention can be made of a larger thickness and has stronger energy absorption, and there is also a base plate 6 made of an aluminum alloy, the UD cloth 8 made of ultra-high molecular weight polyethylene can basically be omitted. The purpose of providing the fiber back plate 7 is to increase elasticity and further absorb energy, thereby reducing blunt injuries to the user. Among them, the UD cloth 8 is an insurance layer added as a safety guarantee, and the EVA foam material 9 is mainly used for close protection of the user, reducing the sudden back concave (bulge on the non-bullet-facing side of the bulletproof plate after being hit) when the bulletproof plate is hit, which causes blunt injuries to the user. The thickness of the EVA foam material 9 is greater than the thickness of the UD cloth 8, and the overall thickness of the fiber back plate 7 is 8mm-10mm

[0034] A damping layer 2 is provided on the bullet-facing surface of the honeycomb body 4. The damping layer 2 is a sheet material formed by laminating and bonding multiple layers of Kevlar fiber cloth. Kevlar fiber cloth is poly(p-phenylene terephthalamide) fiber cloth, which is an aramid composite material. Poly(p-phenylene terephthalamide) is a liquid crystalline rod-shaped molecule with very good thermal stability, fire resistance, chemical resistance, insulation, high strength and modulus. By comparing the physical properties of Kevlar fiber with other fibers, it can be found that Kevlar fiber is 2 to 11 times stronger than asbestos, 1.6 times stronger than high-strength graphite, 3 times stronger than glass fiber, and 5 times stronger than steel fiber of the same weight; and Kevlar fiber has a very low density, almost half of the density of asbestos. It is widely used in aerospace, shipbuilding and friction materials. The thickness of the damping layer is 2mm-4mm. On the one hand, the damping layer can effectively reduce the bullet speed during bullet impact and has strong protective performance. On the other hand, Kevlar fiber is mainly broken during the bulletproof process and rarely explodes. The broken fiber filaments can reduce the leakage of ceramic fragments around the bullet hole, so that more ceramic fragments are retained in the honeycomb body. Even if the next bullet is shot into the bullet hole of the previous bullet, it still has a certain protective ability. Compared with other composite materials, it has a stronger ability to protect against multiple bullets.

[0035] The fiber back plate 7, the honeycomb body 4 and the damping layer 2 are connected as a whole via an adhesive.

[0036] Embodiment 1:

[0037] Step S1:

[0038] Step 1: Prepare a honeycomb body 4, which is made by 3D printing of an aluminum alloy material. The honeycomb body 4 includes a substrate 6 and a honeycomb grid 5. The substrate 6 is 2 mm thick, and the side plate (the plate between two meshes) of the honeycomb grid 5 is 1 mm thick, 10 mm high, and 11 mm long (the side length of the inner hole is 10 mm), thereby obtaining a honeycomb body 4;

[0039] Step 2: preparing a ceramic matrix 3, pressing boron carbide powder into a shape, then siliconizing and sintering the shape to obtain a boron carbide ceramic matrix 3;

[0040] Step 3: Prepare the damping layer 2, and mix 200g / m 2 The Kevlar fiber cloth is double-sidedly coated with glue, and the number of layers is 8. Then, a flat hot press is used to heat-press the cloth to obtain a sheet material, the thickness of which is about 2 mm to 2.3 mm. The sheet material is cut into a shape consistent with the shape of the honeycomb body on a laser cutting machine, so as to obtain the damping layer 2.

[0041] Step 4: Prepare a fiber backboard 7 by stacking and laying 25 layers of 130g / mk2 UD cloth 8, hot pressing and bonding, and obtaining an ultra-high molecular weight polyethylene sheet with a thickness of 3.5mm-4mm. Bond a commercially available 5mm thick EVA foam material 9 on the surface of the ultra-high molecular weight polyethylene sheet to obtain a fiber backboard 7;

[0042] Step S2: 2-4 ultra-high molecular weight polyethylene particles are filled into each mesh of the honeycomb body 4 obtained in step S1, and then the ceramic matrix 3 is added to the mesh of the honeycomb grid 5, at which time the top surface of the ceramic matrix 3 protrudes from the honeycomb grid 5, and is placed in a hot pressing mold and hot pressed on a flat hot press. The hot pressing temperature is 145°C-150°C, the pressure is 10MPa, and the hot pressing time is 1.5h-2h. The ultra-high molecular weight polyethylene is squeezed by pressure after being melted and filled in the gap between the ceramic matrix 3 and the honeycomb grid 5. After the hot pressing is completed, the surface of the ceramic matrix 3 is flush with the opening of the honeycomb body 4, and the excess ultra-high molecular weight polyethylene flows out of the honeycomb body to form flash. After cooling, the excess ultra-high molecular weight polyethylene flash on the surface of the projectile side is removed and the surface is roughened to obtain a basic protective plate;

[0043] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer 2 and the fiber backboard 7 respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, spray 1mm-1.5mm polyurea coating on the surface of the plate, and then wrap it with Oxford cloth to obtain a bulletproof plate.

[0044] Within a range of 15 meters, three shots were fired at the bulletproof plate prepared by the above method using 7.62mm×51mm armor-piercing bullets with an initial velocity of 840±15m / s and back concave depths of 25.6mm, 27.4mm, and 28.1mm respectively.

[0045] Embodiment 2:

[0046] Step S1:

[0047] Step 1: Prepare a honeycomb body 4, which is made by 3D printing of an aluminum alloy material. The honeycomb body 4 includes a substrate 6 and a honeycomb grid 5. The substrate 6 is 2 mm thick, and the side plate (a plate between two meshes) of the honeycomb grid 5 is 1.5 mm thick, 12 mm high, and 15 mm long, to obtain a honeycomb body 4;

[0048] Step 2: preparing a ceramic matrix 3, pressing boron carbide powder into a shape, then siliconizing and sintering the shape to obtain a boron carbide ceramic matrix 3;

[0049] Step 3: Prepare the damping layer 2, and mix 200g / m 2 The Kevlar fiber cloth is double-sidedly coated with glue, and the number of layers is 12. Then, a flat hot press is used to heat-press and mold the sheet material. The sheet material has a thickness of about 2.8 mm to 3.2 mm. The sheet material is cut into a shape consistent with the shape of the honeycomb body on a laser cutting machine to obtain the damping layer 2.

[0050] Step 4: Prepare a fiber backboard 7 by stacking and laying 20 layers of 130g / mk2 UD cloth 8, hot pressing and bonding, with a thickness of 3mm-3.5mm, to obtain an ultra-high molecular weight polyethylene sheet, and bond a commercially available 5mm thick EVA foam material 9 on the surface of the ultra-high molecular weight polyethylene sheet to obtain a fiber backboard 7;

[0051] Step S2: filling each mesh of the honeycomb body 4 obtained in step S1 with 2-4 ultra-high molecular weight polyethylene particles, and then adding the ceramic matrix 3 into the mesh of the honeycomb grid 5, wherein the top surface of the ceramic matrix 3 protrudes from the honeycomb grid 5, and placing the ceramic matrix 3 into a hot pressing mold and hot pressing on a flat hot press, wherein the hot pressing temperature is 145°C-150°C, the pressure is 10MPa, and the hot pressing time is 1.5h-2h. After the ultra-high molecular weight polyethylene is melted, it is squeezed by pressure and filled in the gap between the ceramic matrix 3 and the honeycomb grid 5. After the hot pressing is completed, the surface of the ceramic matrix 3 is flush with the opening of the honeycomb body 4, and the excess ultra-high molecular weight polyethylene flows out of the honeycomb body to form flash. After cooling, the excess ultra-high molecular weight polyethylene flash on the surface of the projectile-facing side is removed, and the surface is roughened to obtain a basic protective plate;

[0052] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer 2 and the fiber backboard 7 respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, spray 1mm-1.5mm polyurea coating on the surface of the plate, and then wrap it with Oxford cloth to obtain a bulletproof plate.

[0053] Within a range of 15 meters, three shots were fired at the bulletproof plate prepared by the above method using 7.62mm×51mm armor-piercing bullets with an initial velocity of 840±15m / s and back concave depths of 23.6mm, 25.4mm, and 24.1mm respectively.

[0054] Embodiment three:

[0055] Step S1:

[0056] Step 1: Prepare a honeycomb body 4, which is made by 3D printing of an aluminum alloy material. The honeycomb body 4 includes a substrate 6 and a honeycomb grid 5. The substrate 6 is 2 mm thick, and the side plate (a plate between two meshes) of the honeycomb grid 5 is 2 mm thick, 13 mm high, and 20 mm long, thereby obtaining a honeycomb body 4;

[0057] Step 2: preparing a ceramic matrix 3, pressing boron carbide powder into a shape, then siliconizing and sintering the shape to obtain a boron carbide ceramic matrix 3;

[0058] Step 3: Prepare the damping layer 2, and mix 200g / m 2 The Kevlar fiber cloth is double-sidedly coated with glue, and the number of layers is 16. Then, a flat hot press is used to heat-press and mold the sheet material. The sheet material has a thickness of about 3.5 mm to 4 mm. The sheet material is cut into a shape consistent with the shape of the honeycomb body on a laser cutting machine to obtain the damping layer 2.

[0059] Step 4: Prepare a fiber backboard 7 by stacking and laying 20 layers of 130g / mk2 UD cloth 8, hot pressing and bonding, with a thickness of 3mm-3.5mm, to obtain an ultra-high molecular weight polyethylene sheet, and bond a commercially available 5mm thick EVA foam material 9 on the surface of the ultra-high molecular weight polyethylene sheet to obtain a fiber backboard 7;

[0060] Step S2: filling each mesh of the honeycomb body 4 obtained in step S1 with 2-4 ultra-high molecular weight polyethylene particles, and then adding the ceramic matrix 3 into the mesh of the honeycomb grid 5, wherein the top surface of the ceramic matrix 3 protrudes from the honeycomb grid 5, and placing the ceramic matrix 3 into a hot pressing mold and hot pressing on a flat hot press, wherein the hot pressing temperature is 145°C-150°C, the pressure is 10MPa, and the hot pressing time is 1.5h-2h. After the ultra-high molecular weight polyethylene is melted, it is squeezed by pressure and filled in the gap between the ceramic matrix 3 and the honeycomb grid 5. After the hot pressing is completed, the surface of the ceramic matrix 3 is flush with the opening of the honeycomb body 4, and the excess ultra-high molecular weight polyethylene flows out of the honeycomb body to form flash. After cooling, the excess ultra-high molecular weight polyethylene flash on the surface of the projectile-facing side is removed, and the surface is roughened to obtain a basic protective plate;

[0061] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer 2 and the fiber backboard 7 respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, spray 1mm-1.5mm polyurea coating on the surface of the plate, and then wrap it with Oxford cloth to obtain a bulletproof plate.

[0062] Within a range of 15 meters, three shots were fired at the bulletproof plate prepared by the above method using 7.62mm×51mm armor-piercing bullets with an initial velocity of 840±15m / s and back concave depths of 31.6mm, 29.4mm, and 31.9mm respectively.

[0063] Comparative Example 1:

[0064] Step S1:

[0065] Step 1: Prepare a honeycomb body 4, which is made by 3D printing of an aluminum alloy material. The honeycomb body 4 includes a substrate 6 and a honeycomb grid 5. The substrate 6 is 1 mm thick, and the side plate (a plate between two meshes) of the honeycomb grid 5 is 2 mm thick, 12 mm high, and 15 mm long, to obtain a honeycomb body 4;

[0066] Step 2: preparing a ceramic matrix 3, pressing boron carbide powder into a shape, then siliconizing and sintering the shape to obtain a boron carbide ceramic matrix 3;

[0067] Step 3: Prepare the damping layer 2, and mix 200g / m 2 The Kevlar fiber cloth is double-sidedly coated with glue, and the number of layers is 16. Then, a flat hot press is used to heat-press and mold the sheet material. The sheet material has a thickness of about 3.5 mm to 4 mm. The sheet material is cut into a shape consistent with the shape of the honeycomb body on a laser cutting machine to obtain the damping layer 2.

[0068] Step 4: Prepare a fiber backboard 7 by stacking and laying 20 layers of 130g / mk2 UD cloth 8, hot pressing and bonding, with a thickness of 3mm-3.5mm, to obtain an ultra-high molecular weight polyethylene sheet, and bond a commercially available 5mm thick EVA foam material 9 on the surface of the ultra-high molecular weight polyethylene sheet to obtain a fiber backboard 7;

[0069] Step S2: Brush the ceramic substrate 3 obtained in step S1 with glue and fill it into the mesh of the honeycomb grid 5, put it into a hot pressing mold and perform hot pressing on a flat hot pressing machine. The hot pressing temperature is 145°C-150°C, the pressure is 10MPa, and the hot pressing time is 1.5h-2h. After the hot pressing is completed, a basic protective plate is obtained;

[0070] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer 2 and the fiber backboard 7 respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, spray 1mm-1.5mm polyurea coating on the surface of the plate, and then wrap it with Oxford cloth to obtain a bulletproof plate.

[0071] Within a range of 15 meters, three shots were fired at the bulletproof plate prepared by the above method using 7.62mm×51mm armor-piercing bullets with an initial velocity of 840±15m / s and back concave depths of 31.6mm, 38.4mm, and 36.1mm respectively.

[0072] Comparative Example 2:

[0073] Step S1:

[0074] Step 1: Prepare a honeycomb body 4, which is made by 3D printing of an aluminum alloy material. The honeycomb body 4 includes a substrate 6 and a honeycomb grid 5. The substrate 6 is 1 mm thick, and the side plate (a plate between two meshes) of the honeycomb grid 5 is 2 mm thick, 10 mm high, and 30 mm long, to obtain a honeycomb body 4;

[0075] Step 2: preparing a ceramic matrix 3, pressing boron carbide powder into a shape, then siliconizing and sintering the shape to obtain a boron carbide ceramic matrix 3;

[0076] Step 3: Prepare the damping layer 2, and mix 200g / m 2 The Kevlar fiber cloth is double-sidedly coated with glue, and the number of layers is 16. Then, a flat hot press is used to heat-press and mold the sheet material. The sheet material has a thickness of about 3.5 mm to 4 mm. The sheet material is cut into a shape consistent with the shape of the honeycomb body on a laser cutting machine to obtain the damping layer 2.

[0077] Step 4: Prepare a fiber backboard 7 by stacking and laying 20 layers of 130g / mk2 UD cloth 8, hot pressing and bonding, with a thickness of 3mm-3.5mm, to obtain an ultra-high molecular weight polyethylene sheet, and bond a commercially available 5mm thick EVA foam material 9 on the surface of the ultra-high molecular weight polyethylene sheet to obtain a fiber backboard 7;

[0078] Step S2: filling each mesh of the honeycomb body 4 obtained in step S1 with 2-4 ultra-high molecular weight polyethylene particles, and then adding the ceramic matrix 3 into the mesh of the honeycomb grid 5, wherein the top surface of the ceramic matrix 3 protrudes from the honeycomb grid 5, and placing the ceramic matrix 3 into a hot pressing mold and hot pressing on a flat hot press, wherein the hot pressing temperature is 145°C-150°C, the pressure is 10MPa, and the hot pressing time is 1.5h-2h. After the ultra-high molecular weight polyethylene is melted, it is squeezed by pressure and filled in the gap between the ceramic matrix 3 and the honeycomb grid 5. After the hot pressing is completed, the surface of the ceramic matrix 3 is flush with the opening of the honeycomb body 4, and the excess ultra-high molecular weight polyethylene flows out of the honeycomb body to form flash. After cooling, the excess ultra-high molecular weight polyethylene flash on the surface of the projectile-facing side is removed, and the surface is roughened to obtain a basic protective plate;

[0079] Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer 2 and the fiber backboard 7 respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, spray 1mm-1.5mm polyurea coating on the surface of the plate, and then wrap it with Oxford cloth to obtain a bulletproof plate.

[0080] Within a range of 15 meters, three rounds of 7.62mm×51mm armor-piercing bullets were used to shoot the bulletproof plate prepared by the above method, with an initial velocity of 840±15m / s. Figure 2 As shown, the depths are 43.7mm, 41.9mm, and 44.1mm respectively.

[0081] It can be seen from the above test data that a smaller honeycomb grid 5 can effectively dissipate energy and has the effect of suppressing back convexity. Thickening the wall thickness of the honeycomb grid 5 has a certain promoting effect on suppressing back convexity and energy dissipation. When the aperture increases to a certain extent, the honeycomb grid 5 will lose its energy dissipation effect.

[0082] The fluctuation range of the back concave depth of the bulletproof plate of comparative example 1 is relatively large. By comparing embodiment 2 with comparative example 1, it can be seen that when the mesh of the honeycomb grid 5 is filled with ultra-high molecular weight polyethylene, the ceramic matrix 3 can have a stronger energy dissipation effect.

[0083] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

Claims

1. A composite reinforced boron carbide bulletproof plate, characterized in that: The invention comprises a honeycomb body (4), wherein the honeycomb body (4) comprises a substrate (6) and a honeycomb grid (5) integrally prepared on the substrate (6); a ceramic matrix (3) is arranged in the mesh of the honeycomb grid (5); ultra-high molecular weight polyethylene is filled between the ceramic matrix (3) and the inner wall of the mesh; a fiber back plate (7) is arranged on the back of the honeycomb body (4); and a damping layer (2) is arranged on the bullet-proof surface; the fiber back plate (7), the honeycomb body (4) and the damping layer (2) are connected as a whole by an adhesive, and are wrapped with an edge layer (1) on the outside.

2. The composite reinforced boron carbide bulletproof plate according to claim 1, characterized in that: The distance between the ceramic substrate (3) and the inner wall of the mesh of the honeycomb grid (5) is less than or equal to 1 mm.

3. The composite reinforced boron carbide bulletproof plate according to claim 1, characterized in that: The honeycomb body (4) is made of aluminum alloy, and the side length of the mesh of the honeycomb grid (5) is 10 mm to 20 mm.

4. The composite reinforced boron carbide bulletproof plate according to claim 1, characterized in that: The damping layer (2) is a sheet material formed by laminating and bonding multiple layers of Kevlar fiber cloth, and the thickness of the damping layer (2) is 2 mm to 4 mm.

5. The composite reinforced boron carbide bulletproof plate according to claim 1, characterized in that: The fiber backboard (7) is a board body formed by compounding a UD cloth (8) and an EVA foam material (9), wherein the thickness of the EVA foam material (9) is greater than the thickness of the UD cloth (8), and the overall thickness of the fiber backboard (7) is 8 mm-10 mm.

6. A method for preparing a composite reinforced boron carbide bulletproof plate, used for preparing the composite reinforced boron carbide bulletproof plate according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: preparing a honeycomb body (4), a ceramic matrix (3), a damping layer (2) and a fiber back plate (7); Step S2: filling the mesh of the honeycomb body (4) obtained in step S1 with ultra-high molecular weight polyethylene particles, then adding the ceramic matrix (3), placing the honeycomb body in a hot pressing mold and hot pressing the honeycomb body on a flat hot pressing machine, removing excess burrs on the surface of the projectile-facing side after cooling, and then grinding the surface to obtain a basic protective plate; Step S3: Brush glue on both surfaces of the basic protective plate obtained in step S2, and bond the damping layer (2) and the fiber back plate (7) respectively, perform hot pressing in an autoclave, slowly cool the plate to below 40°C, take out the plate, and wrap it with an edge layer to obtain a bulletproof plate.

7. The method for preparing the composite reinforced boron carbide bulletproof plate according to claim 6, characterized in that: In step S2, the hot pressing temperature is 145° C.-150° C., the pressure is 10 MPa, and the hot pressing time is 1.5 h-2 h. After the hot pressing is completed, the surface of the ceramic substrate (3) is flush with the mesh opening of the honeycomb body (4).

8. The method for preparing the composite reinforced boron carbide bulletproof plate according to claim 6, characterized in that: In step S3, a 1 mm to 1.5 mm thick polyurea coating is sprayed onto the surface of the plate and then the plate is hemmed with Oxford cloth.

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