An integrated ballistic-resistant composite member

Abstract

The application discloses an integrated bulletproof composite component, which comprises, from a bullet-facing surface to a back surface, a silicon carbide ceramic region, a dense silicon carbide isolation layer, a composition gradient transition region, a carbon fiber unidirectional prepreg layer and a density gradient carbon fiber felt layer in sequence. The silicon carbide ceramic region is composed of multiple silicon carbide structural units and is closed at the bullet-facing surface and connected at the back surface to form a semi-closed gap network. Multiple root system channels extend from the interface between the composition gradient transition region and the carbon fiber unidirectional prepreg layer to the ceramic region, penetrate the dense silicon carbide isolation layer and branch to be connected with the semi-closed gap network. A penetration cutoff region is arranged in the density gradient carbon fiber felt layer to control the resin impregnation depth. The resin filled in the semi-closed gap network, the root system channels and the inner layer of the density gradient carbon fiber felt layer is the same resin system as the prepreg layer and the resin. Thus, a full-thickness integrated energy dissipation path is constructed, the energy dissipation of each functional layer is realized in cooperation, and the overall bulletproof efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of bulletproof armor technology, and in particular relates to an integrated bulletproof composite component. Background Technology

[0002] Ballistic composite components typically employ a structure consisting of a ceramic faceplate and a fiber composite backplate. The ceramic faceplate utilizes a high-hardness fragmentation projectile to dissipate its kinetic energy, while the fiber composite backplate further absorbs residual energy through delamination deformation and tensile fracture. In existing technologies, the ceramic faceplate and composite backplate are generally directly bonded together with an adhesive layer. Upon impact, the ceramic faceplate breaks first, with significant energy reflected at the interface. The adhesive layer rapidly peels off under stress wave action, and ceramic fragments detach from the backplate, unable to transfer the fragmentation energy to other layers for further dissipation. Some designs incorporate through-holes in the ceramic faceplate to guide crack propagation; however, these through-holes compromise the structural integrity of the impact surface, allowing projectiles to embed along the gaps and reducing the effectiveness of the first layer of protection. Resin impregnation on the backplate side is typically uniform, lacking active control over the impregnation depth and distribution area. These shortcomings result in the ceramic faceplate and composite backplate bearing loads independently during actual service, significantly limiting the collaborative energy dissipation efficiency between functional layers. How to construct an integrated energy transfer and dissipation path from the ceramic panel to the composite material backsheet, so that the functional layers can work together, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing an integrated bulletproof composite component. Through the synergistic cooperation of a semi-enclosed gap network, root-like channels, component gradient transition zone, penetration cutoff zone, and the same resin system, an integrated continuous energy transfer and dissipation path is constructed from the internal gap of the ceramic panel through the gradient transition layer to the gradient back plate. This enables each functional layer to participate in energy dissipation in a coordinated manner, thereby improving the overall bulletproof efficiency of the multi-layer bulletproof component.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an integrated bulletproof composite component, comprising, from the front surface to the back surface, the following components in sequence: The silicon carbide ceramic region is composed of multiple silicon carbide structural units. There are gaps between adjacent silicon carbide structural units. The gaps are closed by a silicon carbide solid layer on the side facing the projectile surface and interconnected on the side facing the back, forming a semi-closed gap network that does not penetrate the projectile surface. The silicon carbide solid layer is a solid layer that closes the projectile surface. A dense silicon carbide insulating layer is located on the back side of the silicon carbide ceramic region; The composition gradient transition region is located on the back side of the dense silicon carbide isolation layer, and its composition decreases stepwise from silicon carbide to pure resin. A unidirectional carbon fiber prepreg layer is located on the back side of the composition gradient transition zone; A density gradient carbon fiber felt layer is located on the back side of the unidirectional carbon fiber prepreg layer. The density of the density gradient carbon fiber felt layer decreases in the direction from the unidirectional carbon fiber prepreg layer to the back side. It has a penetration cutoff zone inside. The fiber surface of the penetration cutoff zone is modified with a resin. The felt layer portion outside the penetration cutoff zone retains the original fiber porosity. In addition, multiple root-like channels extend from the interface between the composition gradient transition zone and the carbon fiber unidirectional prepreg layer toward the silicon carbide ceramic region and penetrate the dense silicon carbide isolation layer. The root-like channels branch in the dense silicon carbide isolation layer, and their branch channels are connected to the semi-closed gap network. The semi-closed gap network, the root-like channels, and the felt layer portion located between the permeation stop zone and the carbon fiber unidirectional prepreg layer are filled with resin, and the resin is the same type as the resin contained in the carbon fiber unidirectional prepreg layer and the resin contained in the composition gradient transition zone.

[0005] In the aforementioned integrated bulletproof composite component, the surface of the silicon carbide ceramic region facing the projectile is pre-set with a crack guide grid, which is composed of multiple shallow grooves that do not penetrate the silicon carbide solid layer.

[0006] The root-like channels in the aforementioned integrated bulletproof composite component also meet the following conditions: The main channel of the root-like channel is aligned with the intersection of the crack-guiding grid on the vertical projection plane of the silicon carbide ceramic region. The branch channels of the root-like channels are aligned with the grid lines of the crack-guiding mesh on the vertical projection plane of the silicon carbide ceramic region, and the branch channels of the root-like channels are shallow groove structures with open outer sides.

[0007] The root-like channels in the aforementioned integrated bulletproof composite component also meet the following conditions: The root-like channels have enlarged terminal sinuses at the ends of their branch channels; The root-like channels have a cross-sectional shape that first contracts and then expands at the entrance near the side of the carbon fiber unidirectional prepreg layer.

[0008] In the aforementioned integrated bulletproof composite component, the resin within the semi-closed gap network is a resin containing a reversible Diels-Alder crosslinking network.

[0009] In the aforementioned integrated bulletproof composite component, multiple porous carbon skeleton transition zones are embedded at intervals along the thickness direction within the component gradient transition zone. The porous carbon skeleton transition zones are composed of a carbon skeleton and a resin containing a reversible Diels-Alder crosslinked network filling the pores of the carbon skeleton. The carbon skeleton is a reaction sintering pyrolysis product of thermoplastic polymer fiber felt. The thickness of the multiple porous carbon skeleton transition zones gradually increases in the direction away from the silicon carbide ceramic region.

[0010] In the aforementioned integrated bulletproof composite component, the resin contained in the carbon fiber unidirectional prepreg layer and the resin in the composition gradient transition zone are the same epoxy resin, and the two form a seamless copolymer network at the interface between the composition gradient transition zone and the carbon fiber unidirectional prepreg layer.

[0011] The aforementioned integrated bulletproof composite component, wherein the penetration-blocking zone also meets the following conditions: The resin modification treatment of the permeation cutoff zone is achieved by grafting fluorinated silane onto the fiber surface; The permeation-stopping zone consists of at least one layer of fiber treated with a resin-repellent material.

[0012] The aforementioned integrated bulletproof composite component has a hydrophobic silane treatment layer on the outer surface of the density gradient carbon fiber felt layer.

[0013] Compared with existing technologies, this invention has the following advantages: The silicon carbide solid layer on the projectile-facing side of the semi-enclosed gap network remains closed, preventing projectiles from embedding along the gaps and ensuring the integrity of the first layer of protection. The gaps connected on the back side provide filling space for the resin, guiding cracks to propagate along the pre-designed network during impact, dispersing and transferring ceramic breakage energy rather than releasing it in a concentrated manner. Root-like channels penetrate the dense silicon carbide isolation layer from the backplate side and branch to connect with the semi-enclosed gap network, opening a three-dimensional mass transfer path between the internal gaps of the ceramic panel and the backplate resin system. During injection, the same resin system is injected into the semi-enclosed gap network via the root-like channels. After curing, the ceramic panel, isolation layer, transition zone, and backplate are integrated through the same resin system, eliminating heterogeneous interfaces between functional layers. Stress waves can be continuously transmitted across the entire thickness without reflection loss at the interface. The compositional gradient transition zone achieves asymptotic impedance matching from ceramic to resin through a stepwise decrease in silicon carbide content, further suppressing stress wave reflection near the interface and directing more impact energy into the backplate layers for dissipation. The penetration cutoff zone within the density-gradient carbon fiber felt layer actively controls the resin impregnation depth through resin modification of the fiber surface. This ensures that the felt layer near the ceramic is fully impregnated with resin to form a rigid support, while the felt layer far from the ceramic maintains the original porous state of the fibers to achieve flexible deformation and energy absorption. The backplate itself forms a gradient energy dissipation structure. These features work synergistically to construct an integrated, continuous energy transfer and dissipation path, from the semi-closed gap network of the ceramic panel, through root-like channels and gradient transition zones, to the gradient backplate. This allows each functional layer to collaboratively participate in energy dissipation, improving the overall ballistic resistance efficiency of the multi-layered bulletproof component.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the layered structure of the present invention.

[0016] Explanation of reference numerals in the attached figures: 100, silicon carbide ceramic region; 200, dense silicon carbide isolation layer; 300, compositional gradient transition region; 400, unidirectional carbon fiber prepreg layer; 500, density gradient carbon fiber felt layer; 600, root-like channels; 700, silicon carbide solid layer; 800, penetration stop zone. Detailed Implementation

[0017] like Figure 1As shown, this invention relates to an integrated bulletproof composite component. The component comprises five layers from the projectile-facing side to the back side: a silicon carbide ceramic region 100, a dense silicon carbide insulating layer 200, a compositional gradient transition region 300, a carbon fiber unidirectional prepreg layer 400, and a density-gradient carbon fiber felt layer 500. The component also includes multiple root-like channels 600 located within the dense silicon carbide insulating layer 200. One end of each channel is adjacent to the interface between the compositional gradient transition region 300 and the carbon fiber unidirectional prepreg layer 400, while the other end connects to the semi-enclosed gap network of the silicon carbide ceramic region 100.

[0018] In one embodiment, the silicon carbide ceramic region 100 is composed of multiple silicon carbide structural units spliced ​​together, with gaps between adjacent units. The side of the gap facing the impact surface is closed by the silicon carbide solid layer 700, while the side facing the back remains open and interconnected, thus forming a semi-closed gap network that does not penetrate the impact surface. Viewed from the impact surface, the silicon carbide solid layer 700 makes the impact surface appear as a continuous silicon carbide panel; viewed from the back, the gaps are interconnected to form a network of channels. The surface of the impact surface of the silicon carbide ceramic region 100 can also be pre-set with a crack guiding grid, which consists of multiple shallow grooves that do not penetrate the solid layer. When subjected to impact, the shallow grooves act as stress concentration points, guiding the initial crack propagation direction and preventing random large-scale ceramic fragmentation.

[0019] A dense silicon carbide isolation layer 200 is attached to the back side of the silicon carbide ceramic region 100, and an epoxy resin of the same type as the carbon fiber unidirectional prepreg layer 400 is coated between the two as an adhesive layer. The dense silicon carbide isolation layer 200 is a reaction-sintered dense silicon carbide plate.

[0020] The root-like channels 600 originate from the interface between the compositional gradient transition zone 300 and the carbon fiber unidirectional prepreg layer 400, extend towards the silicon carbide ceramic region 100, and penetrate the dense silicon carbide isolation layer 200. The physical structure of the channels (main holes and branch shallow grooves) is located within the dense silicon carbide isolation layer 200. The channel entrance is located on the back side of the compositional gradient transition zone 300, and the resin within the compositional gradient transition zone 300 permeates to the entrance through each impregnation layer during curing. Each channel consists of two parts: a main hole and branch shallow grooves. The main hole is a through-hole that penetrates from the back side of the compositional gradient transition zone 300 to the projectile-facing side of the dense silicon carbide isolation layer 200. The branch shallow grooves are open shallow grooves machined on the projectile-facing side surface of the dense silicon carbide isolation layer 200, radiating outward from the outlet of the main hole on the projectile-facing side. After lamination and assembly, the back side of the silicon carbide ceramic region 100 is bonded to the impact-facing surface of the dense silicon carbide isolation layer 200, covering and sealing the open surface of the branch shallow grooves, forming a complete resin channel from the back entrance of the composition gradient transition zone 300 through the main hole, branch shallow grooves to the semi-closed gap network of the silicon carbide ceramic region 100. The ends of the branch shallow grooves may have enlarged terminal sinuses (i.e., liquid storage chambers formed by widening and deepening at the ends), and the channel entrance may adopt a cross-sectional shape of first contraction and then expansion. During resin injection, the contraction section guides the resin to concentrate and enters, while the expansion section reduces flow resistance, facilitating uniform filling within the channel. When the impact-facing surface of the silicon carbide ceramic region 100 is machined with a crack-guided grid, the main hole is aligned with the intersection of the crack-guided grid on the vertical projection plane of the silicon carbide ceramic region 100, and the extension direction of the branch shallow grooves is aligned with the grid lines.

[0021] The composition gradient transition zone 300 is located on the back side of the dense silicon carbide isolation layer 200. Its composition decreases stepwise from silicon carbide to pure resin, with eight gradient levels. The highest silicon carbide content layer is 70 wt%, decreasing to zero layer by layer. Each layer is 0.3 mm thick, with a total stacked thickness of 2.4 mm. The transitions between layers are not strictly continuous, but during subsequent co-curing, the resin matrix of adjacent layers diffuses into each other, smoothing the interlayer interfaces. Multiple porous carbon skeleton transition bands can also be embedded at intervals along the thickness direction within the composition gradient transition zone 300. The carbon skeleton is made from the pyrolysis of polyacrylonitrile fiber felt. The thickness of each carbon skeleton gradually increases in the direction away from the silicon carbide ceramic region 100 (thinnest 0.2 mm, thickest 0.5 mm), further smoothing the modulus transition and providing porous skeleton support for the resin matrix containing the Diels-Alder reversible crosslinking network.

[0022] The unidirectional carbon fiber prepreg layer 400 is tightly attached to the pure resin side of the composition gradient transition zone 300. T700 grade carbon fiber bundles are arranged in a single direction and impregnated with epoxy resin, with a resin content of 35 wt%, and the total thickness of the three layers is 0.75 mm. The three layers are stacked at 0° / 90° / 0° to ensure fiber support in all directions. The resin in the unidirectional carbon fiber prepreg layer 400 and the resin used in the composition gradient transition zone 300 are the same epoxy matrix. During subsequent co-curing, the molecular chains at the interface interpenetrate and cross-link, forming a seamless copolymer network with no clear physical delamination at the interface.

[0023] The density gradient carbon fiber felt layer 500 serves as the back layer of the component. It consists of five layers of carbon fiber nonwoven felt sheets of different densities, stacked in descending order of density, with densities starting at 0.30 g / cm³. 3 0.22g / cm 3 0.16g / cm 3 0.11 g / cm 3 0.08g / cm 3 Each layer is 1 mm thick, with a total thickness of 5 mm. A permeation-stop zone 800 is located approximately 2 mm deep from the carbon fiber unidirectional prepreg layer 400, consisting of two layers of carbon fiber felt treated with fluorinated silane grafting modification. The two unmodified felt layers on the side of the permeation-stop zone 800 closest to the carbon fiber unidirectional prepreg layer 400 maintain the original porous state of the fibers, filled with the same resin as the carbon fiber unidirectional prepreg layer 400 and the composition gradient transition zone 300. Because the fiber surface is resin-repellent modified, the permeation-stop zone 800 is not wetted by resin, thus preventing resin from migrating further away from the carbon fiber unidirectional prepreg layer 400, keeping that side of the felt dry and porous. A hydrophobic silane treatment layer can be applied to the outermost surface of the back side of the density gradient carbon fiber felt layer 500 to prevent moisture from the service environment from penetrating the pores of the dry felt layer.

[0024] The inner layers of the semi-closed gap network, root-like channels 600, and density-gradient carbon fiber felt layer 500 (the two felt layers near the carbon fiber unidirectional prepreg layer 400 in the penetration stop zone 800) are filled with resin. This resin is the same type as the resin contained in the carbon fiber unidirectional prepreg layer 400 and the composition gradient transition zone 300. The resin in the semi-closed gap network can have a thermally reversible self-healing function. This function can be achieved by introducing a furan-maleimide Diels-Alder reversible crosslinking system into the epoxy resin. During maintenance, heating is used to make the resin in the cracked area fluid to fill the microcracks. After cooling, the resin's ability to restrain ceramic fragments is restored. All layers of the component use the same type of epoxy resin, and a continuous resin phase is formed between the layers after curing.

[0025] The following describes an exemplary method for preparing this component. Those skilled in the art can also use other known existing processes to manufacture it. The exemplary method described below is not intended to limit the scope of this invention. The silicon carbide ceramic plate and carbon fiber felt in the specific method are commercially available standard products. The unidirectional carbon fiber prepreg is prepared by impregnation using the same formulation as the composition gradient transition zone 300 to ensure that each layer of resin is from the same epoxy system.

[0026] Step 1: Machining and gap pre-filling of silicon carbide ceramic zone 100.

[0027] Purchase commercially available pressureless sintered silicon carbide ceramic plates (density 3.10 g / cm³). 3 Up to 3.18 g / cm 3 The back side is cut into multiple structural units (e.g., 50mm x 50mm blocks) according to the design dimensions (10mm thick). A 3mm thick layer is left uncut on the impact-facing side as a solid layer to seal the gaps. Adjacent units maintain a 1mm gap, forming a continuous silicon carbide panel on the impact-facing side, while the back side is a network of interconnected semi-closed gaps.

[0028] If a crack-guided grid is required, shallow grooves are etched on the projectile-facing surface using a pulsed laser: multiple scans are performed at a target depth of 0.3 mm until the designed depth is reached, with an orthogonal grid spacing of 10 mm and a V-shaped or U-shaped cross-section. The shallow grooves do not penetrate the 3 mm solid layer.

[0029] After completion, the epoxy resin (of the same type as the carbon fiber unidirectional prepreg layer 400 and composition gradient transition zone 300) is preheated to 50-55°C to reduce its viscosity, and then injected into the semi-closed gap network from the back of the silicon carbide ceramic zone 100. During injection, an injection port is provided on the back and an vent is provided on the side to ensure that the resin fills each gap channel. After injection, excess resin on the back is scraped off, and this pre-filled resin remains in stage B (semi-cured state), forming an integral bond with the adjacent resin layers during the subsequent co-curing process.

[0030] As an alternative, such as Figure 1 The structure shown can also be achieved by integral molding of the silicon carbide ceramic zone 100. A porous carbon preform is used as a sacrificial template, which has a three-dimensional interconnected structure that complements the semi-closed gap network. The template is embedded in a green body containing a mixture of silicon carbide powder and carbon source powder, with the top surface of the template 3 mm from the surface of the impact-receiving surface. After compaction, the green body is sintered in argon gas, where liquid silicon infiltrates into the green body and reacts with carbon to form silicon carbide. After sintering, the carbon template is removed, leaving cavities that form a semi-closed gap network. Epoxy resin is then injected from the back to fill the gaps.

[0031] Step 2: Processing and channel pre-filling of dense silicon carbide isolation layer 200.

[0032] Purchase commercially available reaction-bonded silicon carbide plates (3mm thick), and grind and polish the impact-resistant and back surfaces until smooth. Use a picosecond laser to drill through the back surface to form main holes, with a diameter of 1mm, penetrating the plate thickness, or use physical drilling. The hole positions are determined by the vertical projection of the intersection points of the crack guide grid; if there is no crack guide grid, arrange them in a uniform array with a hole spacing of 10mm.

[0033] On the projectile-facing surface of the dense silicon carbide insulating layer 200, shallow grooves are etched using a 355nm ultraviolet laser. These grooves radiate outwards from the outlets of each main aperture, with a depth of 0.5mm, a width of 1mm, a length of 10mm, and a U-shaped cross-section. The ends widen to 2mm and deepen to 1.5mm to form terminal sinuses. The position of these shallow grooves is aligned with the semi-enclosed gap network on the back side of the silicon carbide ceramic region 100.

[0034] Locating pin holes are drilled on both the dense silicon carbide insulating layer 200 and the silicon carbide ceramic region 100 for pin alignment during assembly. The width of the branch shallow groove and the size of the terminal sinus can be enlarged according to the actual situation to absorb accumulated tolerances. For large-area components, the number of locating pin holes can be appropriately increased according to the component size to control the accumulated deviation in the far-field region.

[0035] After the channel is fabricated, epoxy resin (of the same type as the carbon fiber unidirectional prepreg layer 400 and composition gradient transition zone 300) is injected through the main hole inlet on the back side of the dense silicon carbide isolation layer 200, filling the main hole, branch shallow grooves, and terminal sinuses. Vacuum-assisted injection can be used to ensure no air bubbles remain in the channel. The pre-filled resin remains in stage B (semi-cured state) after injection, forming an integral bond with the adjacent resin layers during subsequent co-curing.

[0036] Step 3: Preparation of the composition gradient transition region 300.

[0037] Silicon carbide powder and epoxy resin system were procured. Eight grades of impregnating materials were developed, decreasing in silicon carbide content from 70 wt% to zero. For the high silicon carbide content grades, 2 wt% fumed silica was added to prevent sedimentation, resulting in a paste-like slurry. Each grade of impregnating material was applied to the release film using a precision coating machine to form a uniform impregnating layer. The release film was then removed, and layers were laid in descending order of silicon carbide content: the 70 wt% side facing the dense silicon carbide release layer (200 mm), and the pure resin side facing the carbon fiber unidirectional prepreg layer (400 mm). The high silicon carbide content layers had lower resin content and weaker self-adhesion; a rubber roller was used for gentle pressing to aid adhesion. The total thickness of the eight layers was 2.4 mm. Each impregnating layer was uncured after lamination, already containing resin to fill the gaps between silicon carbide particles and for subsequent curing.

[0038] If a porous carbon skeleton transition zone needs to be embedded, purchase polyacrylonitrile fiber felt sheets and pyrolyze them in nitrogen at a rate of 3°C / min to 1000°C for 2 hours to obtain the porous carbon skeleton. Pyrolysis will cause shrinkage, so the precursor design dimensions need to be pre-compensated. Embed the carbon skeleton sequentially between the impregnated layers in ascending order of thickness: the thinnest 0.2mm is near the 70wt% layer, and the thickest 0.5mm is near the pure resin layer. The local thickness at the carbon skeleton embedding point will increase slightly, and the total composite thickness will be controlled according to the actual cumulative thickness during design. The pores in the carbon skeleton will be filled by the resin from the adjacent impregnated layers during subsequent co-curing.

[0039] The furan-maleimide Diels-Alder reversible crosslinking system can be introduced into the epoxy resin system as a thermally reversible self-healing component, which endows the resin with heat repair ability after curing.

[0040] After fabrication, holes are made at predetermined positions on the main holes of the corresponding dense silicon carbide isolation layer 200, and pre-filled resin is injected.

[0041] Step 4: Preparation of carbon fiber unidirectional prepreg layer 400 and density gradient carbon fiber felt layer 500.

[0042] T700 grade carbon fiber unidirectional fabric was purchased and self-impregnated with epoxy resin of the same formulation as the composition gradient transition zone 300 to produce carbon fiber unidirectional prepreg, with a single layer thickness controlled at 0.25mm and a resin content of 35wt%. After cutting, three layers were stacked at 0° / 90° / 0°, with a total thickness of 0.75mm.

[0043] Purchase commercially available polyacrylonitrile-based carbon fiber nonwoven mat sheets, with a density of 0.30 g / cm³. 3 0.22g / cm 3 0.16g / cm 3 0.11 g / cm 3 0.08g / cm 3 Take one layer of each material, each 1 mm thick, and stack them sequentially to form a density gradient carbon fiber felt layer 500, with a total thickness of 5 mm. Take one layer with a density of 0.16 g / cm³. 3 and 0.11 g / cm 3 The two layers of felt were modified by fluorinated silane grafting: the felt was treated with plasma for 3 minutes to introduce oxygen-containing functional groups on the fiber surface as grafting sites; a 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution (concentration 2wt%, ethanol to water volume ratio 9:1, pH 4.5) was prepared, the activated felt was immersed in the solution for 20 minutes, then rinsed with ethanol and dried at 100°C for 45 minutes.

[0044] Before each batch of modified felt is used, random sampling is conducted to confirm that the surface of the full-thickness fiber achieves a resin-repellent effect.

[0045] Density 0.30 g / cm³ 3 and 0.22g / cm 3 Two layers of unmodified felt were thoroughly impregnated in epoxy resin (the same type of resin as the 400 unidirectional prepreg layer of carbon fiber). After removal, excess resin was scraped off, leaving the pores of the two felt layers pre-filled with resin. Density: 0.16 g / cm³ 3 and 0.11 g / cm 3 Two layers of modified felt with a density of 0.08 g / cm³ 3 The felt sheets are kept dry and not soaked.

[0046] Layup sequence: Following the unidirectional prepreg layer 400, place layers with impregnating resin at a density of 0.30 g / cm³. 3 Felt and 0.22g / cm 3 A felt sheet is placed, followed by a layer of adhesive film, and then a layer of fluorinated silane-grafted material with a density of 0.16 g / cm³ is placed on top. 3 Dry felt sheet, then place a layer of adhesive film, then place a layer with a density of 0.11 g / cm³. 3 Dry-modified felt sheets are then placed on a layer of adhesive film, and finally a layer with a density of 0.08 g / cm³ is applied. 3 Dry-modified felt sheets.

[0047] The adhesive film is an epoxy structural adhesive film, and the resin matrix of the epoxy structural adhesive film is the same resin system as the epoxy resin used in the carbon fiber unidirectional prepreg layer 400.

[0048] At the 0.22 / 0.16 interface, the residual epoxy on the surface of the lower impregnated felt forms an adhesive layer at the interface during hot pressing, achieving bonding between the impregnated felt and the modified dry felt. Between the modified dry felts (0.16 / 0.11, 0.11 / 0.08 interfaces), interlayer bonding is achieved through pre-laid adhesive films that cure after hot pressing. Because fluorinated silane modification imparts resin-repellent properties to the fiber surface, the resin after the adhesive film melts cannot penetrate into the internal pores of the felt, and the outer felt body remains dry throughout.

[0049] Step 5: Layer assembly and curing.

[0050] The following layers are stacked sequentially from the projectile-facing side to the back side: silicon carbide ceramic region 100 (projectile-facing side facing outwards, gaps filled with resin), dense silicon carbide insulating layer 200 (channels filled with resin, shallow grooves facing the back side of silicon carbide ceramic region 100 and aligned with the gaps); an epoxy resin of the same type as carbon fiber unidirectional prepreg layer 400 is coated between the back side of silicon carbide ceramic region 100 and the projectile-facing side of dense silicon carbide insulating layer 200 as an adhesive layer. Next, the composition gradient transition region 300 (70wt% side facing dense silicon carbide insulating layer 200, pure resin side facing carbon fiber unidirectional prepreg layer 400), carbon fiber unidirectional prepreg layer 400, and density gradient carbon fiber felt layer 500 (high-density side impregnated with resin facing carbon fiber unidirectional prepreg layer 400) are stacked sequentially. The layers are then pressed and flattened together.

[0051] The laminate is placed in a hot press mold, and a pressure of 1.5 MPa is applied from the side of the density gradient carbon fiber felt layer 500. The low-density dry felt layer is compressed under pressure. Curing is completed by staged heating. The resin in each layer cures synchronously under heating and pressure, and the same type of resin between adjacent layers forms an integral bond at the interface. To prevent excessive resin migration towards the dry felt layer during the high-temperature, low-viscosity stage, the penetration-stopping zone 800 (the two middle felt layers modified with fluorinated silane) in the density gradient carbon fiber felt layer 500 utilizes its resin-repellent surface properties to prevent resin from wetting the dry felt layer; at the same time, a breathable isolation membrane is laid on the back of the density gradient carbon fiber felt layer 500 as an auxiliary measure to prevent resin leakage to the mold side. After the heat preservation is completed, the pressure is released and the mold is demolded at 2°C / min to room temperature.

[0052] During the cooling process, the stepped component gradient in the 300-layer composition gradient transition zone facilitates a gradual transition in the coefficient of thermal expansion. During co-curing, the interlayer resin diffusion further smooths the interface. Additionally, the elastic deformation and heat absorption shrinkage of the 500-layer porous carbon fiber felt layer with density gradient, along with the synchronized shrinkage of the 400-layer unidirectional prepreg layer and the 300-layer resin of the same type in the composition gradient transition zone, collectively alleviate thermal stress. For large-area components, an intermediate insulation step can be added during the cooling stage to further reduce the peak thermal stress.

[0053] Step 6: Backside hydrophobic treatment.

[0054] After the component has cured, an octyltriethoxysilane treatment solution is prepared and applied to the back of the component by atomization spraying, with two coats. It is then air-dried at room temperature or baked at 70°C, where the silane molecules condense on the fiber surface to form a hydrophobic layer. The spraying method allows for precise control of the penetration depth, ensuring that only the shallow surface fibers of the outer felt layer receive hydrophobic treatment.

[0055] In this invention, during projectile penetration, each layer sequentially relays its force, and the anti-ballistic principle is as follows: First, the silicon carbide ceramic zone 100, with its high hardness, shatters the projectile. Shallow grooves on the impact surface guide the initial cracks along the grid. These grooves, 0.3mm deep, primarily influence the initiation and propagation direction of surface cracks, while the propagation path of deeper cracks is dominated by the impact stress field. After the ceramic breaks apart, the resin cured in the gaps on the back side holds the fragments in place, retaining residual ballistic resistance. The resin in the gaps has a thermally reversible self-healing function. If microcracks develop in the component after multiple impacts, heating during maintenance can make the resin in the cracked area more fluid to fill the microcracks; cooling restores the resin's constraint on the ceramic fragments. The crack grid and the root-like channels 600 are spatially aligned, and the ceramic fragments at the cracks are highly likely to be anchored by the resin at the end of the channels.

[0056] Next, a dense silicon carbide insulating layer 200, a single rigid plate, acts as a second barrier, consuming the remaining kinetic energy of the projectile. The cured resin pillars within the channel connect the back resin layer and the ceramic interlayer resin, resulting in a stronger interlayer bond.

[0057] As the projectile continues its journey, the compositional gradient transition zone 300 comes into play. The silicon carbide content decreases step by step from high to low, resulting in a smooth modulus transition and stress being dispersed rather than concentrated at a single interface. The carbon framework further enhances this effect.

[0058] When the carbon fiber unidirectional prepreg layer reaches 400, the residual kinetic energy is absorbed by both the carbon fiber tensile fracture and interlayer delamination mechanisms. Orthogonal layup ensures that fibers in all directions bear the load.

[0059] Finally, the density gradient carbon fiber felt layer 500 is used to finish the process. The first two layers of pre-impregnated resin felt are bonded together with the carbon fiber unidirectional prepreg layer 400. The last three layers of dry felt consume the last bit of energy through fiber pulling, layering of the density gradient carbon fiber felt layer 500, and pore collapse, thus holding the debris in place.

[0060] Depending on the protection requirements, an additional layer of aramid or ultra-high molecular weight polyethylene fiber anti-stripping layer can be added to the back of the component to capture fragments that may penetrate the density gradient carbon fiber felt layer 500.

[0061] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An integrated bulletproof composite component, characterized in that, From the incoming surface to the back surface, the following are included: The silicon carbide ceramic region is composed of multiple silicon carbide structural units. There are gaps between adjacent silicon carbide structural units. The gaps are closed by a silicon carbide solid layer on the side facing the projectile surface and interconnected on the side facing the back, forming a semi-closed gap network that does not penetrate the projectile surface. The silicon carbide solid layer is a solid layer that closes the projectile surface. A dense silicon carbide insulating layer is located on the back side of the silicon carbide ceramic region; The composition gradient transition region is located on the back side of the dense silicon carbide isolation layer, and its composition decreases stepwise from silicon carbide to pure resin. A unidirectional carbon fiber prepreg layer is located on the back side of the composition gradient transition zone; A density gradient carbon fiber felt layer is located on the back side of the unidirectional carbon fiber prepreg layer. The density of the density gradient carbon fiber felt layer decreases in the direction from the unidirectional carbon fiber prepreg layer to the back side. It has a penetration cutoff zone inside. The fiber surface of the penetration cutoff zone is modified with a resin. The felt layer portion outside the penetration cutoff zone retains the original fiber porosity. In addition, multiple root-like channels extend from the interface between the composition gradient transition zone and the carbon fiber unidirectional prepreg layer toward the silicon carbide ceramic region and penetrate the dense silicon carbide isolation layer. The root-like channels branch in the dense silicon carbide isolation layer, and their branch channels are connected to the semi-closed gap network. The semi-closed gap network, the root-like channels, and the felt layer portion located between the permeation stop zone and the carbon fiber unidirectional prepreg layer are filled with resin, and the resin is the same type as the resin contained in the carbon fiber unidirectional prepreg layer and the resin contained in the composition gradient transition zone.

2. The integrated bulletproof composite component according to claim 1, characterized in that, The surface of the impact-facing area of ​​the silicon carbide ceramic region is pre-set with a crack guiding grid, which is composed of multiple shallow grooves that do not penetrate the silicon carbide solid layer.

3. The integrated bulletproof composite component according to claim 2, characterized in that, The root-like channels also satisfy the following conditions: The main channel of the root-like channel is aligned with the intersection of the crack-guiding grid on the vertical projection plane of the silicon carbide ceramic region. The branch channels of the root-like channels are aligned with the grid lines of the crack-guiding mesh on the vertical projection plane of the silicon carbide ceramic region, and the branch channels of the root-like channels are shallow groove structures with open outer sides.

4. The integrated bulletproof composite component according to claim 1, characterized in that, The root-like channels also satisfy the following conditions: The root-like channels have enlarged terminal sinuses at the ends of their branch channels; The root-like channels have a cross-sectional shape that first contracts and then expands at the entrance near the side of the carbon fiber unidirectional prepreg layer.

5. The integrated bulletproof composite component according to claim 1, characterized in that, The resin within the semi-closed gap network is a resin containing a reversible Diels-Alder crosslinking network.

6. The integrated bulletproof composite component according to claim 5, characterized in that, Multiple porous carbon skeleton transition zones are embedded at intervals along the thickness direction within the composition gradient transition zone. The porous carbon skeleton transition zones are composed of a carbon skeleton and a resin containing a reversible Diels-Alder crosslinking network filling the pores of the carbon skeleton. The carbon skeleton is a reaction sintering pyrolysis product of thermoplastic polymer fiber felt. The thickness of the multiple porous carbon skeleton transition zones gradually increases in the direction away from the silicon carbide ceramic region.

7. The integrated bulletproof composite component according to claim 1, characterized in that, The resin contained in the carbon fiber unidirectional prepreg layer is the same epoxy resin as the resin in the composition gradient transition zone, and the two form a seamless copolymer network at the interface between the composition gradient transition zone and the carbon fiber unidirectional prepreg layer.

8. The integrated bulletproof composite component according to claim 1, characterized in that, The permeation cutoff region also meets the following conditions: The resin modification treatment of the permeation cutoff zone is achieved by grafting fluorinated silane onto the fiber surface; The permeation-stopping zone consists of at least one layer of fiber treated with a resin-repellent material.

9. The integrated bulletproof composite component according to claim 1, characterized in that, The outer surface of the density gradient carbon fiber felt layer has a hydrophobic silane treatment layer.

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