A ceramic fiber composite high-strength helmet and a preparation method thereof

Abstract

The application discloses a ceramic fiber composite high-strength helmet and a preparation method thereof, and belongs to the technical field of helmet manufacturing.The helmet comprises a ceramic fiber composite structure reinforcing unit and a multilayer fiber mixed helmet shell unit, wherein the ceramic fiber composite structure reinforcing unit is covered outside the multilayer fiber mixed helmet shell unit and is used for reinforcing the strength of the multilayer fiber mixed helmet shell unit, and the ceramic fiber composite structure reinforcing unit and the multilayer fiber mixed helmet shell unit are integrally formed or are connected through an adhesive layer.The ceramic fiber composite bulletproof structure of the scheme considers the requirements of protection capacity improvement and lightweight design, adopts multilayer mixed fibers based on different characteristics in the penetration process, and fully plays the mechanical properties of the fibers in each penetration stage; the convex structure is made by using a carbon fiber preform, the high modulus and high strength of the carbon fiber composite material are used to reduce the back convex deformation of the helmet shell after the penetration of the projectile, and the lateral stiffness of the helmet is improved.

Description

Technical Field

[0001] This invention belongs to the field of novel protective materials and processes, specifically a ceramic fiber composite high-strength helmet and its preparation method. Background Technology

[0002] Helmets are an important piece of personal protective equipment used by the military and police, primarily to protect the head from bullets, high-speed fragments from explosions, and other secondary damage. Currently, helmets are mostly made of single or mixed fibers such as aramid or ultra-high molecular weight polyethylene. Material limitations mean that current helmets are generally insufficient to withstand bullets fired from submachine guns or rifles. To comprehensively consider both high-intensity threats and the need for lightweight helmets, major domestic and international ballistic protection standards generally define the protection level of helmets as protection against pistol bullets or high-speed fragments. In certain environments, a direct hit to the head by a rifle bullet poses a serious threat to life; therefore, developing new types of rifle bullet-resistant helmets is of great significance.

[0003] In the prior art, ceramic fiber composite structures are widely used as classic protective structures in torso protection. For example, patent number CN 203657619U discloses a slurry-molded boron carbide-silicon carbide composite ceramic bulletproof helmet. However, a simple ceramic helmet is easily penetrated and cannot meet the protection performance requirements. The high density of ceramics cannot meet the design requirements of lightweight helmets.

[0004] Patent No. CN 219368537U discloses a bulletproof boron carbide ceramic helmet with a buffer mechanism. This helmet mainly solves the impact of the impact force on the head after the helmet is hit by a bullet. However, similarly, a simple ceramic helmet body is difficult to meet the protection performance requirements, and the broken ceramic fragments and bullet fragments can cause great damage to the head.

[0005] Patents CN 213455137U, CN 203964783U, CN 108788641B, CN 108788641A, and CN213455137U disclose the application of titanium alloys in bulletproof helmets. Specifically, they include the molding method of titanium alloy helmets, the composite process with fiber materials, and the helmet production and preparation molds. However, the application of titanium alloys in helmets has problems such as high difficulty in weight reduction, general protective ability, high processing difficulty, and easy ricochet, which can cause secondary injuries to the human body. Moreover, it is not breathable and cannot meet the comfort requirements of wearing for a long time.

[0006] Patent No. CN 208349936U discloses a composite helmet with a honeycomb barrier layer / carbon fiber two-dimensional woven structure fabric / high toughness two-dimensional woven structure. Although the honeycomb ceramic composite short carbon fiber can improve the toughness of ceramic, the low strength of the honeycomb ceramic structure makes it difficult to meet the requirements for absorbing the initial kinetic energy of bullets. The low elongation at break of carbon fiber results in poor penetration resistance. The woven structure causes the fiber to bend and deform, further reducing its penetration resistance.

[0007] Patent No. CN 116872519A discloses a multi-layer fiber composite bulletproof helmet that uses only aramid fiber and polyethylene fiber as composite materials. It can only improve the protection level to NIJ IIIA level, and the back convex deformation does not meet the requirements of national military standards and police bulletproof helmets.

[0008] The above analysis shows that pure ceramic helmets cannot completely absorb all the energy of bullets, and broken ceramic fragments and bullet fragments can easily cause secondary injuries to the head; metal helmets are heavy, have weak protective capabilities, and are prone to ricochets, which can easily cause secondary injuries; helmets with single-fiber or mixed-fiber structures cannot simultaneously meet the technical requirements of lightweight design, improved protective capabilities, and reduced back convexity deformation. Analysis of currently published patents and papers shows that the helmet design methods or technical levels described above cannot balance the requirements of protective capability, lightweighting, and back convexity deformation control. Therefore, this patent addresses these issues by designing a new type of high-strength helmet that takes into account lightweighting requirements, improved protective capabilities, reduced back convexity, and increased lateral stiffness. Summary of the Invention

[0009] To address the aforementioned problems, the present invention aims to provide a ceramic fiber composite high-strength helmet and its preparation method. In order to improve the protective capability of bulletproof helmets, achieve lightweight design of bulletproof helmets, and optimize their practical performance, researchers have carried out a series of optimizations in terms of materials, structure, and processes to meet the technical requirements of upgrading the helmet's protective capability from pistol bullets to rifle bullets.

[0010] The specific technical solution for achieving the objective of this invention is as follows:

[0011] A ceramic fiber composite high-strength helmet includes a ceramic fiber composite structural reinforcement unit and a multi-layer fiber hybrid helmet shell unit.

[0012] The ceramic fiber composite structure reinforcement unit covers the outside of the multi-layer fiber braided helmet shell unit to enhance the strength of the multi-layer fiber braided helmet shell unit.

[0013] The ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed or connected by an adhesive layer.

[0014] Furthermore, the ceramic fiber composite structure reinforcement unit includes a crack-arresting layer and a ceramic layer;

[0015] The crack-resistant layer is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber, carbon fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, with one to three layers.

[0016] The ceramic layer is one of aluminum magnesium boron, boron carbide, silicon carbide, alumina, silicon nitride or other multiphase ceramics, and its thickness is between 1.5 mm and 7.5 mm.

[0017] The crack-resistant layer and the ceramic layer are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

[0018] Furthermore, the ceramic fiber composite structure reinforcement unit also includes an energy-absorbing fiber layer, which is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber mixed fiber, and the structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer mixed structure, with the number of layers between 15 and 50.

[0019] The ceramic layer and the energy-absorbing fiber layer are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

[0020] Furthermore, the multi-layer fiber-woven helmet shell unit sequentially includes an energy-absorbing fiber layer, a convexity-reducing layer, and a rigid support layer;

[0021] The energy-absorbing fiber layer is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer blended structure, with the number of layers between 15 and 50.

[0022] The anti-bumping layer is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and the structure is one of plain weave, twill weave, satin weave and other weave structures.

[0023] The rigid support layer is made of one of the following materials: carbon fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber, or multi-fiber blended fiber reinforced resin matrix composite material, and the fiber weaving structure is one of the following: two-dimensional weave structure, plain weave, satin weave, or twill weave.

[0024] Furthermore, the rigid support layer has two layers, which are respectively disposed on the outer sides of the energy-absorbing fiber layer and the anti-protrusion layer.

[0025] Furthermore, the energy-absorbing fiber layer, the anti-bumping layer, and the rigid support layer are respectively bonded together by hot pressing with an adhesive film, the number of adhesive film layers being 1 to 3, and the adhesive film being polyurethane, vinyl ester resin, or polyethylene resin.

[0026] The crack-resistant layer and the energy-absorbing fiber layer are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

[0027] This invention also provides a method for preparing the above-mentioned ceramic fiber composite high-strength helmet. When the ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed, the preparation process includes:

[0028] Step 1: Cut the crack-stopping layer, energy-absorbing fiber layer, anti-bumping layer, and rigid support layer into fabric pieces of a certain size using fiber prepreg and set them aside. Cut them into the corresponding shapes according to the template.

[0029] Step 2, Pre-forming of energy-absorbing fiber layer and anti-protrusion layer: After the energy-absorbing fiber layer and anti-protrusion layer are cut into shape, the fabric pieces are weighed according to the designed surface density to determine the number of stacking layers. Then, they are stacked sequentially on the punch of the split helmet mold of the hot press. After the mold is closed, the pre-formed parts of energy-absorbing fiber layer and anti-protrusion layer are obtained by heating the punch mold.

[0030] The heating process employs a segmented hot-pressing molding technique: First, after mold closing, the temperature of the helmet punch is raised to 75℃~85℃ at a rate of 3℃ / min, and held for 8min~20min to ensure temperature uniformity across all parts of the helmet within this temperature range; then, the temperature of the helmet punch is raised again to 110℃~150℃, held for 10min~25min, and the holding pressure is 15MPa~25MPa.

[0031] Step 3: The rigid support layer preform of the multi-layer fiber-woven helmet shell unit is prepared by resin injection molding process RTM, including rigid support layer preforming, rigid support layer laying, closed mold compression, resin injection, temperature curing and demolding process.

[0032] The resin-based material of the rigid support layer is one of epoxy resin, polyurethane resin or polyacrylic acid resin, with a resin viscosity between 300 mPa•s and 600 mPa•s and a resin content between 30% and 60%.

[0033] Step 4: Pre-forming of the helmet body. The helmet body is prepared and formed using resin injection molding (RTM) technology. The pre-formed rigid support layer, adhesive film, anti-bumping layer and energy-absorbing fiber layer, adhesive film, crack-resistant layer cloth, adhesive film, ceramic layer, adhesive film and crack-resistant layer cloth are stacked on the helmet mold from bottom to top. Vacuum is drawn to maintain negative pressure. Then the pre-formed parts are placed in a thermostatic precipitator for heat preservation and curing. After demolding, the pre-formed helmet body can be obtained.

[0034] Step 5: Trimming the helmet body preform. Place the obtained helmet body preform on the helmet positioning mold, trim the edges of the helmet body preform using a 3D laser cutting device, then grind the edges smooth, and wrap the helmet sample with rubber edging.

[0035] Step 6: Spray polyurea and paint. Spray 1mm to 1.5mm of polyurea onto the inner and outer surfaces of the helmet sample, and then spray paint to complete the preparation of the one-piece ceramic fiber composite high-strength helmet.

[0036] This invention also provides a method for preparing the above-mentioned ceramic fiber composite high-strength helmet. When the ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are connected by an adhesive layer, the preparation process includes:

[0037] Step 1: Prepare ceramic fiber composite reinforcing units, including:

[0038] (1) Fabric cutting: Cut the fiber material fabric prepreg selected for the crack-stopping layer and energy-absorbing fiber layer into fabric pieces of a certain size for later use, and cut them into corresponding shapes according to the template mold;

[0039] (2) Pre-forming of energy-absorbing fiber layer: After the energy-absorbing fiber layer is cut and shaped, the fabric pieces are weighed according to the designed surface density to determine the number of stacking layers. Then, they are stacked sequentially on the punch of the split helmet mold of the hot press. After the mold is closed, the pre-formed energy-absorbing fiber layer is obtained by heating the punch. The process of heating the punch after the mold is closed is as follows: after the mold is closed, the temperature of the helmet punch is raised to 75℃~85℃ at a rate of 3℃ / min, and the holding time is 8min~20min to ensure the uniformity of temperature of each part of the energy-absorbing fiber layer in this temperature range; then the temperature of the helmet punch is raised again to 110℃~150℃, the holding time is 10min~25min, and the holding pressure is 15MPa~25MPa.

[0040] (3) Pre-forming of ceramic fiber composite structure reinforcement unit: The ceramic fiber composite structure reinforcement unit is prepared and formed by resin injection molding process RTM. The crack arresting layer, ceramic layer and energy absorption fiber layer preforms are stacked from top to bottom on the mold of the reinforcement unit. Vacuum is drawn to maintain negative pressure. Then the preforms are placed in a thermostatic precipitator for heat preservation and curing. After demolding, the preforms of ceramic fiber composite structure reinforcement unit can be obtained.

[0041] The preparation process conditions for the preformed reinforcing unit are: vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 120℃~135℃, curing pressure 1.5MPa~4.5MPa, holding time 15min~25min;

[0042] (4) Trimming of reinforcing unit preforms: The obtained reinforcing unit preforms are placed on the positioning mold and trimmed by a three-dimensional laser cutting device. Then the edges are ground flat and the burrs around the edges are removed.

[0043] Step 2: Prepare multi-layer fiber-woven helmet shell unit:

[0044] (1) Fabric cutting: Cut the fiber material fabric prepreg selected for the rigid support layer, energy-absorbing fiber layer and anti-protrusion layer into fabric pieces of a certain size for later use, and cut them into corresponding shapes according to the template mold;

[0045] (2) Pre-forming of rigid support layer: The rigid support layer is prepared by resin injection molding process, which includes laying rigid support material, mold compression, resin injection, heating and curing and demolding.

[0046] The process conditions are: injection pressure 6–60 bar, vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 80℃~145℃, curing pressure 1.5MPa~4.5MPa, holding time 5min~30min;

[0047] (3) The resin-based material of the rigid support layer is one of epoxy resin, polyurethane resin or polyacrylic resin, with a resin viscosity between 300 mPa·s and 600 mPa·s and a resin content between 30% and 60%.

[0048] (4) Pre-forming of multi-layer fiber hybrid helmet shell unit: The pre-made rigid support layer, the cut fabric pieces of energy-absorbing fiber layer, the cut fabric pieces of anti-convexity layer and the pre-made rigid support layer are weighed according to the designed surface density to determine the number of stacking layers, and then stacked sequentially on the punch of the hot press split helmet mold. After the mold is closed, the pre-made part is obtained by heating the punch mold.

[0049] The process of heating the punch mold after mold closing is a segmented hot pressing molding process: First, after mold closing, the temperature of the multi-layer fiber braided helmet shell punch mold is raised to 75℃~85℃ at a rate of 3℃ / min, and the holding time is 8min~20min to ensure the temperature uniformity of various parts of the helmet within this temperature range; then, the temperature of the helmet punch mold is raised to 110℃~150℃, the holding time is 10min~25min, and the holding pressure is 15MPa~25MPa.

[0050] (5) Trimming of multi-layer fiber hybrid helmet shell unit prefabricated parts: The obtained multi-layer fiber hybrid helmet shell unit is placed on the positioning mold, and the trimming of the multi-layer fiber hybrid helmet shell unit prefabricated parts is completed by three-dimensional laser cutting equipment. Then the edge is ground flat and the burrs around the edge are removed.

[0051] Step 3: Post-process the prepared ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit, and connect the ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit using an adhesive layer to complete the preparation, including:

[0052] The inner and outer surfaces of the prepared ceramic fiber composite structure reinforcement unit and multi-layer fiber braided helmet shell unit are sprayed with 1mm to 1.5mm of polyurea, and then paint is sprayed on their surfaces.

[0053] Finally, the ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are bonded together using an adhesive layer to complete the fabrication.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] This solution offers both modular and integrated helmet structures to meet the requirements of different battlefield environments. Its structure employs a ceramic-fiber hybrid design, utilizing the abrasive and fragmenting effect of ceramics to dissipate most of the projectile's energy, while the tensile and shear deformation of the fibers absorbs the remaining kinetic energy after the projectile is broken by the ceramics. The design incorporates a multi-fiber hybrid structure to fully leverage the energy dissipation function of each fiber layer at different stages of projectile penetration. Specifically, fiber layers with high tensile and shear strength are used as the frontal surface to absorb the projectile's energy at high penetration rates; fiber layers with high deformation capacity and high elongation at break are used as the back surface to buffer the projectile's impact; and finally, fiber layers with appropriate stiffness are used to suppress the helmet's high deformation while simultaneously improving the helmet's lateral stiffness.

[0056] This solution employs a ceramic fiber composite bulletproof structure that balances enhanced protection with lightweight design requirements. Based on the different characteristics of bullet penetration, multi-fiber blends are used to fully utilize the mechanical properties of the fibers at each penetration stage. A carbon fiber preform is used to create a convexity reduction structure, leveraging the high modulus and high strength of carbon fiber composites to reduce the amount of back convexity deformation of the helmet after bullet penetration, while simultaneously improving the helmet's lateral stiffness. Based on this patented novel protective structure, it simultaneously achieves the beneficial effects of modular combination, lightweight reduction, enhanced protection, and control of back convexity deformation.

[0057] The present invention will be further described below with reference to specific embodiments. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the integrated ceramic fiber composite high-strength helmet structure in Embodiment 1 of the present invention.

[0059] Figure 2 This is a schematic diagram of the preparation process of the integrated ceramic fiber composite high-strength helmet in Embodiment 1 of the present invention.

[0060] Figure 3 This is a schematic diagram of the composite ceramic fiber composite high-strength helmet structure in Embodiment 2 of the present invention.

[0061] Figure 4 This is a flowchart of the preparation method of the composite ceramic fiber composite high-strength helmet in Embodiment 2 of the present invention.

[0062] Figure 5 This is a schematic diagram of the overall structure of the ceramic fiber composite high-strength helmet structure of the present invention. Detailed Implementation

[0063] Example

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0066] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0067] Example 1

[0068] Combination Figure 1 A ceramic fiber composite high-strength helmet, comprising a ceramic fiber composite structure reinforcement unit and a multi-layer fiber hybrid helmet shell unit;

[0069] The ceramic fiber composite structure reinforcement unit covers the outside of the multi-layer fiber braided helmet shell unit to enhance the strength of the multi-layer fiber braided helmet shell unit.

[0070] The ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed or connected by an adhesive layer.

[0071] This embodiment describes an integrated ceramic fiber composite high-strength helmet and its preparation method;

[0072] Specifically, the ceramic fiber composite reinforcing unit includes crack-arresting layers 1 and 3 and a ceramic layer 2, wherein the crack-arresting layers consist of two layers.

[0073] The crack-resistant layers 1 and 3 are one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber, carbon fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, with the number of layers ranging from 1 to 3.

[0074] The ceramic layer 2 is one of aluminum magnesium boron, boron carbide, silicon carbide, alumina, silicon nitride or other multiphase ceramics, and its thickness is between 1.5 mm and 7.5 mm.

[0075] The crack-resistant layers 1 and 3 and the ceramic layer 2 are bonded together by hot pressing with an adhesive film. The number of adhesive film layers is 1 to 3, and the adhesive film is made of polyurethane, vinyl ester resin or polyethylene resin.

[0076] The multi-layer fiber hybrid helmet shell unit includes, in sequence, an energy-absorbing fiber layer 4, a convexity-reducing layer 5, and a rigid support layer 6.

[0077] The energy-absorbing fiber layer 4 is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and its structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer blended structure, with the number of layers between 15 and 50.

[0078] The anti-bumping layer 5 is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and its structure is one of plain weave, twill weave, satin weave and other weave structures.

[0079] The rigid support layer 6 is made of one of the following materials: carbon fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber, or multi-fiber blended fiber reinforced resin matrix composite material, and the fiber weaving structure is one of the following: two-dimensional weave structure: plain weave, satin weave, or twill weave.

[0080] In addition, the energy-absorbing fiber layer 4, the anti-bumping layer 5 and the rigid support layer 6 are respectively bonded together by hot pressing with an adhesive film. The number of adhesive film layers is 1 to 3, and the adhesive film is polyurethane, vinyl ester resin or polyethylene resin.

[0081] In addition, the crack-resistant layer 3 and the energy-absorbing fiber layer 4 are bonded together by hot pressing with an adhesive film. The number of adhesive film layers is 1 to 3, and the adhesive film is polyurethane, vinyl ester resin or polyethylene resin.

[0082] Combination Figure 2 The method for preparing the integrated ceramic fiber composite high-strength helmet in this embodiment includes:

[0083] Step 1: Cut crack-stopping layers 1 and 3, energy-absorbing fiber layer 4, anti-bumping layer 5, and rigid support layer 6 into fabric pieces of a certain size using fiber fabric prepreg, and cut them into corresponding shapes according to the template.

[0084] Step 2, Pre-forming of energy-absorbing fiber layer 4 and anti-protrusion layer 5: After cutting and shaping the fabric pieces of energy-absorbing fiber layer 4 and anti-protrusion layer 5, weigh them according to the designed surface density to determine the number of stacking layers, and then stack them sequentially on the punch of the split helmet mold of the hot press. After the mold is closed, the preform of the ceramic fiber composite structure reinforcement unit is obtained by heating the punch mold.

[0085] The heating process employs a segmented hot-pressing molding technique: First, after mold closing, the temperature of the helmet punch is raised to 75℃~85℃ at a rate of 3℃ / min, and held for 8min~20min to ensure temperature uniformity across all parts of the helmet within this temperature range; then, the temperature of the helmet punch is raised again to 110℃~150℃, held for 10min~25min, and the holding pressure is 15MPa~25MPa.

[0086] Step 3: The rigid support layer 6 preform of the multi-layer fiber-woven helmet shell unit is prepared by resin injection molding process RTM, including rigid support layer preforming, rigid support layer laying, closed mold compression, resin injection, temperature curing and demolding process.

[0087] The resin-based material of the rigid support layer 6 is one of epoxy resin, polyurethane resin or polyacrylic acid resin, with a resin viscosity between 300 mPa•s and 600 mPa•s and a resin content between 30% and 60%.

[0088] Step 4: Pre-forming of the helmet body. The helmet body is prepared and formed using resin injection molding (RTM) process. The pre-formed parts of the rigid support layer 6, the adhesive film, the anti-bumping layer 5 and the energy-absorbing fiber layer 4, the adhesive film, the crack-stopping layer 3 fabric piece, the adhesive film, the ceramic layer 2, the adhesive film, and the crack-stopping layer 1 fabric piece are stacked on the helmet mold from bottom to top. A vacuum is drawn to maintain negative pressure. Then the pre-formed parts are placed in an autoclave for heat preservation and curing. After demolding, the pre-formed helmet body can be obtained.

[0089] Step 5: Trimming the helmet body preform. Place the obtained helmet body preform on the helmet positioning mold, trim the edges of the helmet body preform using a 3D laser cutting device, then grind the edges smooth, and wrap the helmet sample with rubber edging.

[0090] Step 6: Spray polyurea and paint. Spray 1mm to 1.5mm of polyurea onto the inner and outer surfaces of the helmet sample, and then spray paint to complete the preparation of the one-piece ceramic fiber bulletproof helmet.

[0091] Example 2

[0092] Combination Figure 3 A ceramic fiber composite high-strength helmet, comprising a ceramic fiber composite structure reinforcement unit and a multi-layer fiber hybrid helmet shell unit;

[0093] The ceramic fiber composite structure reinforcement unit covers the outside of the multi-layer fiber braided helmet shell unit to enhance the strength of the multi-layer fiber braided helmet shell unit.

[0094] The ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed or connected by an adhesive layer.

[0095] This embodiment describes a combined ceramic fiber composite high-strength helmet connected by an adhesive layer and its preparation method.

[0096] Specifically, the ceramic fiber composite structure reinforcement unit 1 includes a crack-arresting layer 1-1 and a ceramic layer 1-2, and also includes an energy-absorbing fiber layer 1-3;

[0097] The crack-resistant layer 1-1 is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber, carbon fiber or multi-fiber blended fiber, and its structure is one of two-dimensional braided structures, with the number of layers ranging from 1 to 3.

[0098] The ceramic layer 1-2 is one of aluminum magnesium boron, boron carbide, silicon carbide, alumina, silicon nitride or other multiphase ceramics, and its thickness is between 1.5 mm and 7.5 mm.

[0099] The crack-resistant layer 1-1 and the ceramic layer 1-2 are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

[0100] Energy-absorbing fiber layers 1-3 are one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer blended structure, with the number of layers ranging from 15 to 50.

[0101] The ceramic layer 1-2 and the energy-absorbing fiber layer 1-3 are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

[0102] The multi-layer fiber hybrid helmet shell unit includes, in sequence, an energy-absorbing fiber layer 3-2, a convexity-reducing layer 3-3, and rigid support layers 3-1 and 3-4. The rigid support layers 3-1 and 3-4 are respectively disposed on the outer side of the energy-absorbing fiber layer and the rigid support layer.

[0103] The energy-absorbing fiber layer 3-2 is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and its structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer blended structure, with the number of layers between 15 and 50.

[0104] The anti-protrusion layer 3-3 is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and its structure is one of plain weave, twill weave, satin weave and other weave structures.

[0105] The rigid support layers 3-1 and 3-4 are made of one of the following: carbon fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber, or multi-fiber blended fiber reinforced resin matrix composite material; and the fiber weaving structure is one of the following: two-dimensional weave structure: plain weave, satin weave, or twill weave.

[0106] In addition, the adhesive layer uses Velcro.

[0107] Combination Figure 4 The preparation method of the combined ceramic fiber composite high-strength helmet described in this embodiment includes the following steps:

[0108] Step 1: Prepare ceramic fiber composite reinforcing units, including:

[0109] (1) Fabric cutting: Cut the anti-crack layer and energy-absorbing fiber layer into fabric pieces of a certain size using the selected fiber material prepreg for later use, and cut them into corresponding shapes according to the template.

[0110] (2) Pre-forming of energy-absorbing fiber layer: After the energy-absorbing fiber layer is cut and shaped, the fabric pieces are weighed according to the designed surface density to determine the number of stacking layers. Then, they are stacked sequentially on the hot press split helmet mold, that is, the punch of the designed multi-layer fiber hybrid helmet shell unit. After the mold is closed, the pre-formed energy-absorbing fiber layer is obtained by heating the punch mold. The process of heating the punch mold after the mold is closed is as follows: after the mold is closed, the temperature of the helmet punch mold is raised to 75℃~85℃ at a rate of 3℃ / min, and the heat preservation time is 8min~20min to ensure the uniformity of temperature of each part of the energy-absorbing fiber layer in this temperature range; then the temperature of the helmet punch mold is raised again to 110℃~150℃, the heat preservation time is 10min~25min, and the pressure is 15MPa~25MPa.

[0111] (3) Pre-forming of ceramic fiber composite structure reinforcement unit: The ceramic fiber composite structure reinforcement unit is prepared and formed by resin injection molding process RTM. The crack arresting layer, ceramic layer and energy absorption fiber layer preforms are stacked from top to bottom on the mold of the reinforcement unit. Vacuum is drawn to maintain negative pressure. Then the preforms are placed in a thermostatic precipitator for heat preservation and curing. After demolding, the preforms of ceramic fiber composite structure reinforcement unit can be obtained.

[0112] The preparation process conditions for the preformed reinforcing unit are: vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 120℃~135℃, curing pressure 1.5MPa~4.5MPa, holding time 15min~25min;

[0113] (4) Trimming of reinforcing unit preforms: The obtained reinforcing unit preforms are placed on the positioning mold and trimmed by a three-dimensional laser cutting device. Then the edges are ground flat and the burrs around the edges are removed.

[0114] Step 2: Prepare multi-layer fiber-woven helmet shell unit:

[0115] (1) Fabric cutting: Cut the fiber material fabric prepreg selected for the rigid support layer, energy-absorbing fiber layer and anti-protrusion layer into fabric pieces of a certain size for later use, and cut them into corresponding shapes according to the template mold;

[0116] (2) Pre-forming of rigid support layers 3-1 and 3-4: The rigid support layers are prepared by resin injection molding process, which includes laying rigid support material, mold compression, resin injection, heating curing and demolding.

[0117] The process conditions are: injection pressure 6–60 bar, vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 80℃~145℃, curing pressure 1.5MPa~4.5MPa, holding time 5min~30min;

[0118] (3) The resin-based material of the rigid support layer 3-1 and the rigid support layer 3-4 is one of epoxy resin, polyurethane resin or polyacrylic resin, the resin viscosity is between 300 mPa·s and 600 mPa·s, and the resin content is between 30% and 60%.

[0119] (4) Pre-forming of multi-layer fiber hybrid helmet shell unit: The pre-made rigid support layer, the cut fabric pieces of energy-absorbing fiber layer, the cut fabric pieces of anti-convexity layer and the pre-made rigid support layer are weighed according to the designed surface density to determine the number of stacking layers, and then stacked sequentially on the punch of the hot press split helmet mold. After the mold is closed, the pre-made part is obtained by heating the punch mold.

[0120] The process of heating the punch mold after mold closing is a segmented hot pressing molding process: First, after mold closing, the temperature of the punch mold of the multi-layer fiber braided helmet shell 3 is raised to 75℃~85℃ at a rate of 3℃ / min, and the holding time is 8min~20min to ensure the uniformity of temperature in all parts of the helmet within this temperature range; then the temperature of the helmet punch mold is raised to 110℃~150℃, the holding time is 10min~25min, and the holding pressure is 15MPa~25MPa.

[0121] (5) Trimming of multi-layer fiber hybrid helmet shell unit prefabricated parts: The obtained multi-layer fiber hybrid helmet shell unit is placed on the positioning mold, and the trimming of the multi-layer fiber hybrid helmet shell unit prefabricated parts is completed by three-dimensional laser cutting equipment. Then the edge is ground flat and the burrs around the edge are removed.

[0122] Step 3: Post-process the prepared ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit, and connect the ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit using an adhesive layer to complete the preparation, including:

[0123] The inner and outer surfaces of the prepared ceramic fiber composite structure reinforcement unit and multi-layer fiber braided helmet shell unit are sprayed with 1mm to 1.5mm of polyurea, and then paint is sprayed on their surfaces.

[0124] Finally, the ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are bonded together using an adhesive layer to complete the fabrication. The structural pattern is shown in Figure 5.

[0125] The combined and integrated helmet structures provided by this solution can meet the requirements of use in different battlefield environments. The structure adopts a ceramic fiber hybrid structure, which utilizes the abrasive and fragmentation effect of ceramics to consume most of the projectile's energy, and uses the tensile and shear deformation of fibers to absorb the remaining kinetic energy after the projectile is broken by ceramics. The design of multi-fiber hybrid fiber structure makes full use of the energy dissipation role of each fiber layer at different stages of projectile penetration. Specifically, fiber layers with high tensile and shear strength are used as the front surface to absorb the energy of the projectile at high penetration rates, fiber layers with high deformation capacity and high breaking elongation are used as the back surface to buffer the impact of the projectile, and finally, fiber layers with appropriate stiffness are used to suppress the high deformation of the helmet shell while improving the lateral stiffness of the helmet shell.

[0126] This patented ceramic fiber composite bulletproof structure balances enhanced protection with lightweight design requirements. It employs a multi-fiber blend based on the different characteristics of bullet penetration, fully utilizing the mechanical properties of fibers at each penetration stage. A carbon fiber preform is used to create a convexity reduction structure, leveraging the high modulus and strength of carbon fiber composites to reduce the amount of convex deformation of the helmet shell after bullet penetration, while simultaneously improving the helmet's lateral stiffness. Based on this novel protective structure, it simultaneously achieves the beneficial effects of modular combination, lightweight reduction, enhanced protection, and control of convex deformation.

[0127] The embodiments described above are merely one implementation method of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A ceramic fiber composite high-strength helmet, characterized in that, Including ceramic fiber composite structure reinforcement units and multi-layer fiber braided helmet shell units; The ceramic fiber composite structure reinforcement unit covers the outside of the multi-layer fiber braided helmet shell unit to enhance the strength of the multi-layer fiber braided helmet shell unit. The ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed or connected by an adhesive layer. The ceramic fiber composite structure reinforcement unit includes a crack-arresting layer and a ceramic layer; The crack-resistant layer is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber, carbon fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, with one to three layers. The ceramic layer is one of aluminum magnesium boron, boron carbide, silicon carbide, alumina, silicon nitride or other multiphase ceramics, and its thickness is between 1.5 mm and 7.5 mm. The crack-resistant layer and the ceramic layer are bonded together by hot pressing with an adhesive film. The number of adhesive film layers is 1 to 3, and the adhesive film is made of polyurethane, vinyl ester resin or polyethylene resin. The ceramic fiber composite structure reinforcement unit also includes an energy-absorbing fiber layer, which is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber mixed fiber, and the structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer mixed structure, with the number of layers between 15 and 50. The ceramic layer and the energy-absorbing fiber layer are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

2. The ceramic fiber composite high-strength helmet according to claim 1, characterized in that, The multi-layer fiber hybrid helmet shell unit includes, in sequence, an energy-absorbing fiber layer, a convexity-reducing layer, and a rigid support layer; The energy-absorbing fiber layer is one of ultra-high molecular weight polyethylene fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and the structure is one of two-dimensional braided structure, three-dimensional braided form or multi-fiber layer blended structure, with the number of layers between 15 and 50. The anti-bumping layer is one of aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, nylon fiber, glass fiber or multi-fiber blended fiber, and its structure is one of plain weave, twill weave or satin weave structure. The rigid support layer is made of one of the following materials: carbon fiber, aramid fiber, PBO fiber, nylon fiber, glass fiber, or multi-fiber blended fiber reinforced resin matrix composite material, and the fiber weaving structure is one of the following: two-dimensional weave structure, plain weave, satin weave, or twill weave.

3. The ceramic fiber composite high-strength helmet according to claim 2, characterized in that, The rigid support layer has two layers, which are respectively disposed on the outside of the energy-absorbing fiber layer and the anti-protrusion layer.

4. The ceramic fiber composite high-strength helmet according to claim 2, characterized in that, The energy-absorbing fiber layer, the anti-bumping layer, and the rigid support layer are respectively bonded together by hot pressing with an adhesive film. The number of adhesive film layers is 1 to 3, and the adhesive film is polyurethane, vinyl ester resin, or polyethylene resin. The crack-resistant layer and the energy-absorbing fiber layer are bonded together by hot pressing with an adhesive film. The adhesive film consists of 1 to 3 layers and is made of polyurethane, vinyl ester resin, or polyethylene resin.

5. The method for preparing a ceramic fiber composite high-strength helmet according to claim 2, characterized in that, When the ceramic fiber composite reinforcement unit and the multi-layer fiber braided helmet shell unit are integrally formed, the manufacturing process includes: Step 1: Cut the crack-stopping layer, energy-absorbing fiber layer, anti-bumping layer, and rigid support layer into fabric pieces of a certain size using fiber prepreg and set them aside. Cut them into the corresponding shapes according to the template. Step 2, Pre-forming of energy-absorbing fiber layer and anti-protrusion layer: After the energy-absorbing fiber layer and anti-protrusion layer are cut into shape, the fabric pieces are weighed according to the designed surface density to determine the number of stacking layers. Then, they are stacked sequentially on the punch of the split helmet mold of the hot press. After the mold is closed, the pre-formed parts of energy-absorbing fiber layer and anti-protrusion layer are obtained by heating the punch mold. The heating process employs a segmented hot-pressing molding technique: First, after mold closing, the temperature of the helmet punch is raised to 75℃~85℃ at a rate of 3℃ / min, and held for 8min~20min to ensure temperature uniformity across all parts of the helmet within this temperature range; then, the temperature of the helmet punch is raised again to 110℃~150℃, held for 10min~25min, and the holding pressure is 15MPa~25MPa. Step 3: The rigid support layer preform of the multi-layer fiber-woven helmet shell unit is prepared by resin injection molding process RTM, including rigid support layer preforming, rigid support layer laying, closed mold compression, resin injection, temperature curing and demolding process. The resin-based material of the rigid support layer is one of epoxy resin, polyurethane resin or polyacrylic acid resin, with a resin viscosity between 300 mPa•s and 600 mPa•s and a resin content between 30% and 60%. Step 4: Pre-forming of the helmet body. The helmet body is prepared and formed using resin injection molding (RTM) technology. The pre-formed rigid support layer, adhesive film, anti-bumping layer and energy-absorbing fiber layer, adhesive film, crack-resistant layer cloth, adhesive film, ceramic layer, adhesive film and crack-resistant layer cloth are stacked on the helmet mold from bottom to top. Vacuum is drawn to maintain negative pressure. Then the pre-formed parts are placed in a thermostatic precipitator for heat preservation and curing. After demolding, the pre-formed helmet body can be obtained. Step 5: Trimming the helmet body preform. Place the obtained helmet body preform on the helmet positioning mold, trim the edges of the helmet body preform using a 3D laser cutting device, then grind the edges smooth, and wrap the helmet sample with rubber edging. Step 6: Spray polyurea and paint. Spray 1mm to 1.5mm of polyurea onto the inner and outer surfaces of the helmet sample, and then spray paint to complete the preparation of the one-piece ceramic fiber composite high-strength helmet.

6. The method for preparing a ceramic fiber composite high-strength helmet according to claim 2, characterized in that, When the ceramic fiber composite reinforcing unit and the multi-layer fiber-woven helmet shell unit are connected by an adhesive layer, the manufacturing process includes: Step 1: Prepare ceramic fiber composite reinforcing units, including: (1) Fabric cutting: Cut the fiber material fabric prepreg selected for the crack-stopping layer and energy-absorbing fiber layer into fabric pieces of a certain size for later use, and cut them into corresponding shapes according to the template. (2) Pre-forming of energy-absorbing fiber layer: After the energy-absorbing fiber layer is cut and shaped, the fabric pieces are weighed according to the designed surface density to determine the number of stacking layers. Then, they are stacked sequentially on the punch of the split helmet mold of the hot press. After the mold is closed, the pre-formed energy-absorbing fiber layer is obtained by heating the punch. The process of heating the punch after the mold is closed is as follows: after the mold is closed, the temperature of the helmet punch is raised to 75℃~85℃ at a rate of 3℃ / min, and the holding time is 8min~20min to ensure the uniformity of temperature of each part of the energy-absorbing fiber layer in this temperature range; then the temperature of the helmet punch is raised again to 110℃~150℃, the holding time is 10min~25min, and the holding pressure is 15MPa~25MPa. (3) Pre-forming of ceramic fiber composite structure reinforcement unit: The ceramic fiber composite structure reinforcement unit is prepared and formed by resin injection molding process RTM. The crack arresting layer, ceramic layer and energy absorption fiber layer preforms are stacked from top to bottom on the mold of the reinforcement unit. Vacuum is drawn to maintain negative pressure. Then the preforms are placed in a thermostatic precipitator for heat preservation and curing. After demolding, the preforms of ceramic fiber composite structure reinforcement unit can be obtained. The preparation process conditions for the preformed reinforcing unit are: vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 120℃~135℃, curing pressure 1.5MPa~4.5MPa, holding time 15min~25min; (4) Trimming of reinforcing unit preforms: The obtained reinforcing unit preforms are placed on the positioning mold and trimmed by a three-dimensional laser cutting device. Then the edges are ground flat and the burrs around the edges are removed. Step 2: Prepare multi-layer fiber-woven helmet shell unit: (1) Fabric cutting: Cut the fiber material fabric prepreg selected for the rigid support layer, energy-absorbing fiber layer and anti-protrusion layer into fabric pieces of a certain size for later use, and cut them into corresponding shapes according to the template mold; (2) Pre-forming of rigid support layer: The rigid support layer is prepared by resin injection molding process, which includes laying rigid support material, mold compression, resin injection, heating and curing and demolding. The process conditions are: injection pressure 6–60 bar, vacuum degree 10. ﹣1 MPa ~ 10 ﹣2 MPa, curing temperature 80℃~145℃, curing pressure 1.5MPa~4.5MPa, holding time 5min~30min; (3) The resin-based material of the rigid support layer is one of epoxy resin, polyurethane resin or polyacrylic resin, with a resin viscosity between 300 mPa·s and 600 mPa·s and a resin content between 30% and 60%. (4) Pre-forming of multi-layer fiber hybrid helmet shell unit: The pre-made rigid support layer, the cut fabric pieces of energy-absorbing fiber layer, the cut fabric pieces of anti-convexity layer and the pre-made rigid support layer are weighed according to the designed surface density to determine the number of stacking layers, and then stacked sequentially on the punch of the hot press split helmet mold. After the mold is closed, the pre-made part is obtained by heating the punch mold. The process of heating the punch mold after mold closing is a segmented hot pressing molding process: First, after mold closing, the temperature of the multi-layer fiber braided helmet shell punch mold is raised to 75℃~85℃ at a rate of 3℃ / min, and the holding time is 8min~20min to ensure the temperature uniformity of various parts of the helmet within this temperature range; then, the temperature of the helmet punch mold is raised to 110℃~150℃, the holding time is 10min~25min, and the holding pressure is 15MPa~25MPa. (5) Trimming of multi-layer fiber hybrid helmet shell unit prefabricated parts: The obtained multi-layer fiber hybrid helmet shell unit is placed on the positioning mold, and the trimming of the multi-layer fiber hybrid helmet shell unit prefabricated parts is completed by three-dimensional laser cutting equipment. Then the edge is ground flat and the burrs around the edge are removed. Step 3: Post-process the prepared ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit, and connect the ceramic fiber composite reinforcement unit and multi-layer fiber braided helmet shell unit using an adhesive layer to complete the preparation, including: The inner and outer surfaces of the prepared ceramic fiber composite structure reinforcement unit and multi-layer fiber braided helmet shell unit are sprayed with 1mm to 1.5mm of polyurea, and then paint is sprayed on their surfaces. Finally, the ceramic fiber composite structure reinforcement unit and the multi-layer fiber braided helmet shell unit are bonded together using an adhesive layer to complete the fabrication.

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