Continuous fiber reinforced three-dimensional woven composite bulletproof helmet and preparation method thereof

Abstract

The invention discloses a continuous fiber reinforced three-dimensional woven composite bulletproof helmet and a preparation method thereof. The method comprises the following steps: firstly, designing an axial lining yarn organization structure with a stable structure; carrying out three-dimensional surveying and mapping on a helmet mold, and carrying out one-time forming knitting on the bulletproof helmet preform through flat knitting local knitting and a holding ring type needle retracting and releasing knitting method according to the three-dimensional hyperboloid structure of the helmet by adopting the axial lining yarn tissue structure; and then carrying out compression molding by adopting a resin film permeation process to prepare the continuous fiber reinforced composite bulletproof helmet. The bulletproof helmet made of the three-dimensional woven composite material is compact in structure, free of layering, uniform in overall thickness, free of lap joint and reinforcement of a main body material, continuous in fiber distribution, free of buckling, uniform in quality, high in material utilization rate and stable in performance, and meets the protection requirement. The defects that a traditional bulletproof helmet is tedious in process, low in production efficiency, high in processing cost, low in material utilization rate, discontinuous in fiber fracture, poor in manual layering and size stability and the like are overcome.

Description

Technical Field

[0001] The present invention belongs to the field of woven composites, and particularly relates to a continuous fiber-reinforced three-dimensional woven composite bulletproof helmet and a preparation method thereof. Background Art

[0002] Bulletproof helmets protect the heads of combatants and improve the survival ability of soldiers on the battlefield by absorbing and decomposing the kinetic energy of projectiles or fragments, reducing penetration ability, and preventing penetration. They have become one of the important components of individual protective equipment.

[0003] Modern military bulletproof helmets have complex curved surfaces. They are usually made by cutting, splicing, and laminating non-woven or woven fabric prepregs and then pressing them into shape. In the process of fabric layering, the required fabric needs to be cut, spliced, and laminated. This process has the disadvantages of being cumbersome and complex, time-consuming, high labor cost, poor product integrity, and waste of raw materials. At the same time, the fabrics used to prepare composite helmets are mostly woven from high-performance fibers. On the one hand, cutting will inevitably cause waste of expensive materials (material utilization rate is less than 70%), increasing production costs. On the other hand, during the process of laying the prepreg slices in a staggered manner layer by layer, there will be a large number of overlapping parts, resulting in weak points in protection and uneven thickness of the product. At the same time, due to the need for trimming to varying degrees in the actual operation process, the quality uniformity and performance stability of the product are affected. In order to improve the continuity of fibers in bulletproof helmets, new fabric structures and overlapping sequences need to be designed.

[0004] Due to the reinforcing effect of axial reinforcing yarns, warp-knitted axial knitted structures have superior in-plane mechanical properties and structural stability. Due to the straight laying of yarns, the rigidity and strength of fibers are maximally exerted. Under high-speed impact, energy can be quickly propagated in the in-plane direction, enabling the material to have a large in-plane absorption energy. However, warp-knitted axial fabrics are planar structures and cannot be directly shaped into bulletproof helmets with complex curved surfaces. If warp-knitted multi-axial fabrics are used to prepare bulletproof helmets, they must be cut.

[0005] Using the computerized flat knitting machine three-dimensional full-shaping technology, the one-time shaping of complex three-dimensional curved surfaces can be easily achieved. Using this technology, CN 113085052 B and CN 107475887 B disclose a knitting method for a transverse knitting full-shaped helmet shell preform and its helmet shell. However, due to the crimpability of its fibers, the mechanical properties of the three-dimensional knitted structure cannot be fully exerted, the fabric structure is not stable enough, and it does not have bulletproof ability.

[0006] Therefore, there is a need for a three-dimensional woven composite bulletproof helmet with continuous non-buckling axial fibers and a stable structure. Summary of the Invention

[0007] In view of the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a continuous fiber reinforced three-dimensional braided composite bulletproof helmet and a preparation method thereof.

[0008] The present invention designs a new type of axial knitted fabric structure with closely arranged fibers and stable fabric structure. Then, according to this fabric structure, using the computerized flat knitting machine three-dimensional full shaping technology, a three-dimensional braided fabric shell with an overall structure similar to the helmet shape is prepared as the helmet preform. Laying is carried out at multiple angles in the direction consistent with the helmet shape, and then impregnation is carried out through the resin film penetration process, and molding is carried out using the compression molding process, and a continuous fiber reinforced three-dimensional braided composite bulletproof helmet is obtained through post-processing.

[0009] In order to achieve the above purpose, the present invention can be realized through the following technical solutions:

[0010] A preparation method for a continuous fiber reinforced three-dimensional braided composite bulletproof helmet preform, comprising the following steps:

[0011] 1) Design an axial backing yarn organizational structure with stable structure as the organizational structure of the three-dimensional helmet preform;

[0012] 2) Conduct three-dimensional surveying and mapping on the helmet mold. According to the three-dimensional hyperbolic structure of the helmet, using the above-mentioned axial backing yarn organizational structure, through flat knitting local knitting and holding loop type knitting and dropping stitches method, one-time forming knitting is carried out on the bulletproof helmet preform.

[0013] In the above method step 1), the axial backing yarn organizational structure includes two kinds of yarns, namely braiding yarn and non-buckling backing yarn, and the basic unit knitting process is as follows:

[0014] The first row: The non-buckling backing yarn weaves a row of non-buckling reinforcing yarn in the form of weft insertion;

[0015] The second row: The braiding yarn weaves 1 row of 1 + 1 rib;

[0016] The third row: Turn all the yarns on the back needle bed that did not participate in the knitting of the second row to the front needle bed;

[0017] The fourth row: The non-buckling backing yarn weaves a row of non-buckling reinforcing yarn in the form of weft insertion;

[0018] The fifth row: Use the other half of the knitting needles that did not participate in the knitting of the second row to weave 1 row of 1 + 1 rib;

[0019] The sixth row: Turn all the yarns on the back needle bed of the 1 + 1 rib row knitted in the second row to the front needle bed;

[0020] A total of six process rows complete one knitting cycle.

[0021] Repeat the above basic unit weaving process to complete the weaving of the axial warp-knitted fabric structure.

[0022] For the above-mentioned axial warp-knitted fabric structure, the key point of its weaving is that the knitting needles on the rear needle bed all start with empty needles, and after passing through the three process rows of tucking, weft insertion, and knitting in sequence, all the loops on the rear needle bed knitted in the previous time are tucked to the front needle bed to complete the bundled weaving of the warp yarn. Figure 1 This is the knitting diagram of the axial warp-knitted fabric structure proposed by the present invention; Figure 2 This is the front structure of the fabric knitted with the axial warp-knitted fabric structure proposed by the present invention; Figure 3 This is the reverse structure of the fabric knitted with the axial warp-knitted fabric structure proposed by the present invention.

[0023] In the above method steps, the yarns used for the knitting yarn include one or more of high-strength polyester, aramid, PBO, polyimide fiber, or ultra-high molecular weight polyethylene (UHMWPE); the yarns used for the non-crimp warp yarn include one or more of high-strength polyester, aramid, PBO, polyimide fiber, carbon fiber, glass fiber, or ultra-high molecular weight polyethylene (UHMWPE).

[0024] When the axial reinforcement structure is subjected to impact, it mainly absorbs energy through the deformation and transverse propagation of the non-crimp reinforcement yarns. Therefore, in order to ensure the bulletproof performance of the helmet, the mass ratio of the non-crimp warp yarn in the preform should reach more than 70%.

[0025] According to an embodiment of the present invention, the yarn of the knitting yarn is selected from the aramid filament yarn of brand 529S with a denier of 200D produced by Yantai Taihe New Materials Co., Ltd.; the yarn of the non-crimp warp yarn is selected from the aramid filament yarn of brand 629T with a total of 3000D (2×1500D) produced by Yantai Taihe New Materials Co., Ltd.

[0026] The continuous fiber reinforced three-dimensional knitted composite bulletproof helmet preform prepared by the above method also belongs to the protection scope of the present invention.

[0027] Another object of the present invention is to provide a bulletproof helmet preform with a resin film coated on its surface.

[0028] The helmet preform with a resin film coated on its surface provided by the present invention is obtained by coating the resin film on the bulletproof helmet preform obtained above, so as to obtain a helmet preform with a resin film coated on its surface.

[0029] Furthermore, according to the areal density of the fabric of the bulletproof helmet preform, a resin film matching its areal density is selected to control the resin content of the final preform between 8% and 18%.

[0030] Another object of the present invention is to provide a bulletproof helmet.

[0031] The bulletproof helmet provided by the present invention uses the three-dimensional braided helmet preform coated with a resin film prepared above, first performs multi-angle layering in the direction consistent with the helmet shape, and then is formed by a molding process. After trimming, spraying, and installing suspension accessories, a continuous fiber-reinforced three-dimensional braided composite bulletproof helmet is obtained.

[0032] Further, the layering method is orthogonal placement. According to the areal density requirement of the bulletproof helmet and the areal density of the prepared preform, the number of layers is calculated. For example, when the areal density of the prepared preform containing the film is 400 g / m 2 ², the number of layers laid can be 20 layers.

[0033] Further, the molding process can be mold hot pressing.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] 1) The manufacturing method of the composite material bulletproof helmet involved in the present invention adopts a three-dimensional braiding and one-piece forming technology. Since there is no need for fabric cutting and splicing, the effective utilization rate of materials can reach more than 80%, significantly reducing the material cost; the three-dimensional preform of the helmet is completed by an automated braiding device controlled by a program. The preform is an integral structure with uniform areal density, no overlap, no need for local reinforcement, and no structural weak points. The composite material bulletproof helmet involved in the present invention has stable product performance, few human influencing factors, and good quality consistency.

[0036] 2) The three-dimensional braided preform prepared by the present invention adopts the axial lining yarn organizational structure proposed by the present invention, which has a stable structure and continuous fibers. The reinforcing lining yarn has no breakage and no buckling, and the proportion is between 70% and 90%, solving the problems of loose structure and insufficient bulletproof performance of the three-dimensional braided helmet preform. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the braiding diagram of the axial lining yarn organizational structure proposed by the present invention;

[0038] Figure 2 is the front structure of the fabric braided with the axial lining yarn organizational structure proposed by the present invention;

[0039] Figure 3 is the reverse structure of the fabric braided with the axial lining yarn organizational structure proposed by the present invention;

[0040] Figure 4 is the schematic structural diagram of the continuous fiber-reinforced three-dimensional braided composite bulletproof helmet of the present invention at different angles;

[0041] Figure 5It is a two-dimensional unfolded plane figure from the front to the rear of the continuous fiber reinforced three-dimensional braided composite material bulletproof helmet of the present invention;

[0042] Figure 6 for Figure 5 Partial knitting process diagram of the selected area. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0044] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0045] Example 1

[0046] A 3D knitting computerized flat knitting machine with a machine gauge of E 7.2 and equipped with a high-position roller produced by Stoll Company of Germany was used to knit a continuous fiber reinforced 3D knitted helmet preform. The specific knitting method is as follows:

[0047] The helmet mold is three-dimensionally mapped to obtain its helmet digital model, such as Figure 4 The helmet model is processed using a computer program, and the three-dimensional model of the helmet is expanded in two dimensions to obtain its two-dimensional plane figure, as shown in Figure 5 shown.

[0048] Computer flat knitting machine programming software is used, according to the two-dimensional unfolding drawing of the helmet three-dimensional model and the axial lining yarn structure proposed by the present invention, local knitting and loop holding and releasing needle technology are adopted to compile the three-dimensional knitting program and machine file of the helmet.

[0049] A 200D 529S aramid yarn and two 1500D 629T aramid yarns with a total of 3000D produced by Yantai Taihe New Materials Co., Ltd. are selected as braiding yarn and non-buckling lining yarn respectively, and the present invention is adopted, such as Figure 1 The axial lining yarn weaving structure shown is used to perform one-step forming weaving of the three-dimensional helmet shell. Since the lining yarn is very thick, a presser foot is used to press down and flatten the lining yarn in order to enable the subsequent weaving and binding yarn to be smoothly woven.

[0050] According to the two-dimensional unfolded drawing of the helmet, the helmet is divided into 24 knitting areas along the knitting direction and knitted sequentially. In the 1st to 12th knitting areas, through the technique of adding stitches, the knitting width is gradually increased, and the maximum number of knitting stitches is 86, 106, 126, 150, 170, 186, 202, 214, 224, 230, 234, 236 stitches in sequence. Then, in the 13th to 24th knitting areas, through the techniques of transferring loops and decreasing stitches and the technique of knitting stitches, the knitting width is gradually decreased, and the maximum number of knitting stitches is 236, 234, 230, 224, 214, 202, 186, 170, 150, 126, 106, 86 stitches in sequence.

[0051] In each knitting area, the wedge knitting (also known as partial knitting) technique is adopted. Through the form of holding loops and releasing stitches for adding and decreasing stitches, some of the knitted stitches temporarily withdraw from knitting during the knitting process but the loops on them do not drop off, and re-enter knitting when needed. Its partial knitting procedure is as Figure 6 shown.

[0052] To ensure uniform yarn feeding tension during the knitting process, a yarn feeder is used to control the knitting tensions of the knitting yarn and the lining yarn. The knitting yarn and the lining yarn pass through the tension spring, the LGL yarn storage type yarn feeder, and the Meimingge EFS920 electronic yarn feeder in sequence and then enter the knitting yarn nozzle. The EFS920 electronic yarn feeder controls the yarn feeding tension. Among them, the yarn feeding tension of the knitting yarn is set to 12 cN, and the tension of the lining yarn is set to 30 cN.

[0053] A total of 10 three-dimensional knitted helmet preforms reinforced with continuous aramid fibers with a knitting areal density of 700 g / m 2 are prepared.

[0054] Take the epoxy resin film with an areal density of 100 g / m 2 produced by Xianning Haiwei Composite Material Products Co., Ltd., and evenly spread it on the above-prepared three-dimensional knitted helmet preform with an areal density of 700 g / m 2 to obtain a three-dimensional helmet preform with a resin film, and its resin content is 12.5%.

[0055] Stack the three-dimensional helmet preform with the film layer by layer in the same orientation order as the helmet shape, and a total of 10 layers are laid. Then, place it in a forming mold and hot press it. Forming conditions: pressure 30 MPa, heat up to 160 °C, keep warm for 10 min, pick up and deflate, hot press for 10 min, pick up and deflate, and then hot press for 10 min. After curing is completed, the composite bulletproof helmet shell is obtained. After trimming, spraying, and installing suspension accessories, the composite bulletproof helmet is made.

[0056] This bulletproof helmet is a three-dimensional braided aramid helmet with a dense structure, no delamination, uniform overall thickness, no overlap of the main material, no reinforcement, continuous fiber distribution, no buckling, uniform quality and stable performance to meet the protection requirements, and the material utilization rate is over 80%.

[0057] Example 2

[0058] Use a three-dimensional knitting computer flat knitting machine with high-position rollers and machine number E 7.2 produced by Stoll Company of Germany to knit a preform of a continuous fiber-reinforced three-dimensional knitted helmet. The specific knitting method is as follows:

[0059] Perform three-dimensional mapping on the helmet mold to obtain its helmet digital model. Use a computer program to process the data of the helmet model, and perform two-dimensional unfolding on the three-dimensional helmet model to obtain its two-dimensional planar graph.

[0060] Use the computer flat knitting machine programming software. According to the two-dimensional unfolding drawing of the helmet three-dimensional model and the axial backing yarn organizational structure proposed by the present invention, adopt local knitting and holding loop knitting and purling techniques to compile the three-dimensional knitting program and the file for mounting on the machine of the helmet.

[0061] Select aramid filaments of grade 529S with 100D produced by Yantai Taihe New Materials Co., Ltd. and aramid filaments with 1500D as the knitting yarn and the non-buckling backing yarn respectively. Adopt the axial backing yarn organizational structure knitting structure as shown in the present invention, and adopt the wedge knitting (also known as local knitting) technique. Through the holding loop knitting and purling form of adding needles and decreasing needles, perform one-time forming knitting of the aramid three-dimensional helmet shell. Figure 1 As shown, perform one-time forming knitting of the aramid three-dimensional helmet shell. Through the holding loop knitting and purling form of adding needles and decreasing needles, perform one-time forming knitting of the aramid three-dimensional helmet shell.

[0062] To ensure uniform yarn feeding tension during the knitting process, use a yarn feeder to control the knitting tensions of the knitting yarn and the backing yarn. The knitting yarn and the backing yarn pass through the tension spring, the LGL yarn storage type yarn feeder and the Meimingge EFS920 electronic yarn feeder in sequence and then pass through the knitting yarn nozzle. Control the yarn feeding tension through the EFS920 electronic yarn feeder. Among them, the yarn feeding tension of the knitting yarn is set to 12 cN, and the tension of the backing yarn is set to 30 cN.

[0063] A total of 16 continuous fiber-reinforced three-dimensional knitted helmet preforms with a surface density of 380 g / m 2 are knitted.

[0064] Select aramid filaments of 100D produced by Yantai Taihe New Materials Co., Ltd. as the knitting yarn and T700 carbon fiber as the backing yarn. Adopt the backing yarn reinforced knitting structure as shown in the present invention, and adopt the wedge knitting (also known as local knitting) technique. Through the holding loop knitting and purling form of adding needles and decreasing needles, perform knitting of the carbon fiber-reinforced three-dimensional helmet shell. Figure 1 As shown, perform knitting of the carbon fiber-reinforced three-dimensional helmet shell. Through the holding loop knitting and purling form of adding needles and decreasing needles, perform knitting of the carbon fiber-reinforced three-dimensional helmet shell.

[0065] To ensure uniform yarn feeding tension during the weaving process, a yarn feeder is used to control the weaving tension of the weaving yarn and the warp yarn. The weaving yarn and the warp yarn pass through the LGL yarn storage type yarn feeder and the Meimingge EFS920 electronic yarn feeder in sequence and then penetrate into the weaving yarn nozzle. The EFS920 electronic yarn feeder is used to control the yarn feeding tension. Among them, the yarn feeding tension of the weaving yarn is set to 10 cN, and the tension of the warp yarn is set to 25 cN.

[0066] A total of 4 continuous carbon fiber reinforced three-dimensional woven helmet preforms with a woven areal density of 400 g / m 2 are produced.

[0067] Take the epoxy resin film with an areal density of 50 g / m 2 produced by Xianning Haiwei Composite Material Products Co., Ltd., and evenly lay it on the above-prepared three-dimensional woven aramid helmet preform and carbon fiber helmet preform to obtain a helmet three-dimensional preform with a resin film.

[0068] Orthogonally lay up the helmet three-dimensional carbon fiber preform with the film, a total of 4 layers are laid, and then the aramid preform is laid. The laying method is to stack them layer by layer in a cross-over manner, and a total of 16 layers are laid to make a helmet blank mold, which is put into a forming mold and hot-pressed. Forming conditions: pressure 35 MPa, heating to 160 °C, holding for 10 min, picking up and deflating, hot-pressing for 10 min, picking up and deflating, and then hot-pressing for 10 min. After curing is completed, an aramid-carbon fiber composite bulletproof helmet shell is obtained. After trimming, spraying, and installing suspension accessories, a composite bulletproof helmet is made.

[0069] The inner bullet-proof surface of this bulletproof helmet is a carbon fiber preform, and the outer bullet-facing surface is an aramid fiber preform, which comprehensively utilizes the excellent properties of two high-performance fibers, aramid fiber and carbon fiber. Its structure is dense, without delamination, the overall thickness is uniform, the main material has no overlap, no reinforcement, the fibers are continuously distributed, without buckling, and the quality is uniform and the performance is stable to meet the protection requirements.

[0070] Live ammunition tests and 17-grain simulated fragment V50 tests were carried out on the helmets prepared in Examples 1-2.

[0071] After testing, a 1954 model 7.62 mm pistol was used, and the prepared bulletproof helmet was tested with a 1951 model 7.62 mm pistol bullet (lead core). When the bullet speed was 453 m / s, the helmet of Example 1 was not penetrated, and the bullet mark height was 14 mm. The helmet of Example 2 was not penetrated when the bullet speed was 455 m / s, and the bullet mark height was 19 mm.

[0072] According to the GJB5115A-2012 standard, the weight of the bare helmet of the helmet in Example 1 is 1032 g, and the V50 test result of its 17-grain simulated fragment is 660 m / s. The weight of the bare helmet of the helmet in Example 2 is 1018 g, and the V50 test result of its 17-grain simulated fragment is 665 m / s.

Claims

1. A preparation method for a preform of a continuous fiber reinforced three-dimensional braided composite bulletproof helmet, comprising the following steps: 1) Design an axially inserted yarn tissue structure with stable structure as the tissue structure of the three-dimensional helmet preform; 2) Conduct three-dimensional surveying and mapping on the helmet mold. According to the three-dimensional hyperboloid structure of the helmet, adopt the above-mentioned axially inserted yarn tissue structure, and through horizontal knitting local knitting and holding loop knitting and dropping stitches method, conduct one-time forming knitting on the bulletproof helmet preform.

2. According to the preparation method described in claim 1, it is characterized in that: In the step 1), the axially inserted yarn tissue structure contains two kinds of yarns, namely knitting yarn and non-buckling inserted yarn, and the basic unit knitting process is as follows: The first row: The non-buckling inserted yarn weaves a row of non-buckling reinforced inserted yarn in the form of weft insertion; The second row: The knitting yarn weaves 1 row of 1+1 rib; The third row: Turn all the yarns on the back needle bed that did not participate in the knitting of the second row to the front needle bed; The fourth row: The non-buckling inserted yarn weaves a row of non-buckling reinforced yarn in the form of weft insertion; The fifth row: Use the other half of the knitting needles that did not participate in the knitting of the second row to weave 1 row of 1+1 rib; The sixth row: Turn all the yarns on the back needle bed of the 1+1 rib knitted in the second row to the front needle bed; A total of six process rows complete one knitting cycle.

3. According to the preparation method described in claim 2, it is characterized in that: The proportion of the non-buckling inserted yarn in the preform is more than 70%, and its fineness is 10-30 times that of the knitting yarn.

4. According to the preparation method described in any one of claims 1-3, it is characterized in that: For the axially inserted yarn tissue structure, the key point of knitting is that the knitting needles on the back needle bed all start with empty needles, and after passing through the three process rows of turning needles, weft insertion and knitting in sequence, turn all the yarns on the back needle bed of the previous knitting to the front needle bed to complete the binding knitting of the inserted yarn.

5. According to the preparation method described in any one of claims 1-4, it is characterized in that: The yarns used for the knitting yarn include one or more of high-strength polyester, aramid, PBO, polyimide fiber and ultra-high molecular weight polyethylene (UHMWPE); the yarns used for the non-buckling inserted yarn include one or more of high-strength polyester, aramid, PBO, carbon fiber, polyimide fiber, glass fiber and ultra-high molecular weight polyethylene (UHMWPE).

6. A preform of a continuous fiber reinforced three-dimensional braided composite bulletproof helmet prepared by the method described in any one of claims 1-5.

7. A bulletproof helmet preform with a resin film coated on the surface, which is obtained by coating the resin film on the preform of the continuous fiber reinforced three-dimensional braided composite bulletproof helmet described in claim 6 to obtain a helmet preform with a resin film coated on the surface; preferably, the resin content of the preform is controlled between 8-18%.

8. A bulletproof helmet, which first conducts multi-angle layering on the bulletproof helmet preform with a resin film coated on the surface described in claim 7 in the direction consistent with the helmet shape, and then adopts a molding process to form. After trimming, spraying and installing suspension accessories, a continuous fiber reinforced three-dimensional braided composite bulletproof helmet is obtained.

9. The bulletproof helmet according to claim 8, characterized in that: the laying method is orthogonal placement, and the number of layers is calculated according to the areal density requirement of the bulletproof helmet and the areal density of the prepared preform.

10. The bulletproof helmet according to claim 8, characterized in that: the molding process is hot press molding with a mold.

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