Homogeneous bulletproof helmet shell and preparation method thereof

Abstract

The present invention provides a homogeneous bulletproof helmet shell and a method for preparing the same, comprising the following steps: performing a three-dimensional scan of the outer surface of the helmet shell to establish a three-dimensional curved surface model of the helmet shell; drawing a plurality of dividing lines on the three-dimensional curved surface model, the dividing lines intersecting at the center point of the helmet top, thereby dividing the helmet curved surface into a plurality of equal parts; performing a two-dimensional planar unfolding of the divided curved surface along the corresponding dividing lines, while leaving the top area undivided, to obtain a cut piece shape; rotating the dividing lines sequentially at different angles about the center point of the top of the head, and repeating the dividing and unfolding steps to obtain a plurality of cut piece shapes; cutting prepreg according to a plurality of cut piece shapes, sequentially laying the plurality of cut pieces on a helmet mold in a butt-jointed manner, preforming, and then press-curing to obtain the helmet shell. The preparation method of the present invention can avoid wrinkles caused by the mismatch between the cut piece shapes and the helmet outer shape, and can also improve the uniformity of the helmet shell, thereby improving the overall ballistic performance of the helmet.

Description

Technical Field

[0001] This invention relates to the field of bulletproof protective equipment technology, and in particular to a homogeneous bulletproof helmet shell and its preparation method. Background Art

[0002] Current methods for manufacturing bulletproof helmet shells typically involve first cutting prepreg into shapes such as circles, impellers, or petals, then overlapping and layering these layers, and finally heat-pressing and curing them. However, the current prepreg pieces are drawn and trimmed based on experience, resulting in an inability to perfectly fit the helmet's shape. Furthermore, the overlapping layering method causes prepreg to accumulate at the lower edge of the helmet, leading to uneven overall structure and affecting its ballistic performance. An effective solution to this problem is still lacking.

[0003] Patent CN107289816A discloses a bulletproof helmet and its manufacturing method, wherein the helmet shell is formed by pressing a circular sheet of non-woven fabric made of multiple layers of ultra-high molecular weight polyethylene fiber or film. Although the cut pieces of the bulletproof helmet prepared by this method undergo some deformation and slippage during the high-temperature pressing process, which can fill some missing material areas, this deformation and slippage are very limited, and many wrinkles will still inevitably occur, leading to a reduction in bulletproof performance. Patent CN117341232A discloses a method for preparing a high-performance bulletproof helmet shell, which selects ultra-high molecular weight polyethylene non-woven fabric with a molecular weight of 3-5 million as the main bulletproof material and polyethylene plain weave prepreg fabric as the outer material; it designs various sizes of cut pieces, then uses these different sizes of cut pieces to lay the helmet shell, and finally presses it with a mold to obtain the helmet shell. The invention uses a method of overlapping and layering large and small cut pieces and a circular reinforcing piece on the top of the helmet, which to some extent compensates for the lack of material in the upper part of the helmet caused by the accumulation of cut pieces at the lower edge of the helmet. However, the overall uniformity of the helmet still needs to be improved.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a homogeneous bulletproof helmet shell and its preparation method, which can improve the overall uniformity of the helmet shell, thereby improving the overall bulletproof performance of the helmet.

[0006] In a first aspect, the present invention provides a method for preparing a homogeneous bulletproof helmet shell, comprising the following steps:

[0007] S1. Perform a three-dimensional scan of the outer surface of the helmet shell to establish a three-dimensional curved surface model of the helmet shell;

[0008] S2. Draw several dividing lines on the three-dimensional curved surface model. The dividing lines intersect at the center point of the top of the helmet, dividing the helmet surface into several equal parts.

[0009] S3. Unfold the segmented curved surface along the corresponding dividing lines in a two-dimensional plane, leaving the top area unsegmented, to obtain a piece shape.

[0010] S4. Rotate the dividing line around the center point of the top of the head at different angles in sequence, and repeat the above steps S2-S3 to obtain several piece shapes.

[0011] S5. Cut the prepreg into multiple pieces, lay the multiple pieces on the helmet mold in sequence by joining them together, pre-form, and then mold and cure to obtain the helmet shell.

[0012] Preferably, step S1 includes: using a 3D scanner to perform a 3D scan on the outer surface of the helmet shell to obtain a point cloud map, and then using software to reverse model and establish a 3D curved surface model of the helmet shell.

[0013] Preferably, in step S2, the helmet surface is divided into 4 to 8 equal parts.

[0014] Preferably, step S3 includes: unfolding the segmented curved surface along the corresponding dividing line in a two-dimensional plane, and then forming a circular area with the center point of the top of the head as the center of the central region of the unfolded graphic to obtain a piece shape.

[0015] Preferably, the radius of the circular region is 50-70 mm.

[0016] Preferably, in step S4, the angle is 10-25°; more preferably, it is rotated clockwise by 10-25° in sequence.

[0017] Preferably, in step S5, the number of layers in the layup is 17-24.

[0018] Preferably, in step S5, the prepreg is an aramid woven prepreg (preferably a plain weave structure), coated with phenolic resin on one side, and its areal density is 200-500 g / m³. 2 The mass percentage of phenolic resin in these samples is between 8% and 15%.

[0019] Preferably, in step S5, the preforming temperature is 90±3℃, the pressure is 10±1MPa, and the time is 120±5s.

[0020] Preferably, the molding and curing temperature is 145±3℃, the pressure is 23±1MPa, and the time is 900±5s.

[0021] In a second aspect, the present invention provides a homogeneous bulletproof helmet shell, which is prepared by the above-described method for preparing a homogeneous bulletproof helmet shell.

[0022] The present invention has at least the following beneficial effects:

[0023] (1) The present invention establishes a three-dimensional curved surface model of the helmet shell based on the shape of the helmet shell, divides the curved surface by dividing lines and unfolds it into a piece shape, and forms an undivided area in the center of the piece, which can avoid wrinkles caused by the piece shape not fitting the helmet shape, while ensuring the ballistic performance of the top of the helmet.

[0024] (2) In this invention, multiple cut pieces formed by dividing lines at different angles are laid on a helmet mold in sequence by butt joint, pre-formed, and finally molded and cured. The butt joint laying method avoids the phenomenon of material piling up at the lower edge of the helmet due to the overlap of cut pieces, further improving the overall uniformity of the bulletproof helmet, thereby improving the overall ballistic protection performance of the bulletproof helmet. Attached Figure Description

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Top view of the three-dimensional curved surface model of the helmet shell provided by the present invention Figure 1 .

[0027] Figure 2 Top view of the three-dimensional curved surface model of the helmet shell provided by the present invention Figure 2 .

[0028] Figure 3 This is a front view of the three-dimensional curved surface model of the helmet shell provided by the present invention.

[0029] Figure 4 Schematic diagram of the cut piece shape provided by the present invention Figure 1 .

[0030] Figure 5 Schematic diagram of the cut piece shape provided by the present invention Figure 2 .

[0031] Explanation of the attached labels: 1. 3D curved surface model of the helmet shell; 2. Dividing line; 3. Center point of the top of the head; 4. Circular area. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, 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.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example 1

[0036] like Figures 1 to 5As shown, a 3D scanner was used to perform a 3D scan of the outer surface of the MICH bulletproof helmet shell to obtain a point cloud map. Then, CATIA software was used for reverse modeling to establish a 3D curved surface model 1 of the bulletproof helmet shell. Three dividing lines 2 were drawn on this 3D curved surface model, intersecting at the center point 3 of the helmet's top. The included angle between adjacent dividing lines 2 was 60°, dividing the helmet surface into 6 equal parts. The divided surface was then unfolded in two dimensions along the corresponding dividing lines 2. The central area of ​​the unfolded shape was then optimized into a circular area 4 with a radius of 60mm centered at the center point 3 of the top of the head, thus obtaining a piece shape. The dividing lines 2 were rotated 12° clockwise around the center point 3 of the top of the head, and the above operations of dividing the curve and unfolding the surface in two dimensions were repeated to obtain all the piece shapes required for the bulletproof helmet. All piece shapes were exported and numbered and laid out in CAD software.

[0037] Using a surface density of 350 g / m³ 2 Aramid woven prepreg with a resin content of 10% was cut and numbered according to the above-mentioned pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of the bulletproof helmet, the resin-containing side of the aramid prepreg sheets was always facing down. On the male mold of the molding machine, following the shape of the helmet mold, 24 layers were sequentially laid using a butt-layup method. Pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, at 145℃ and 23MPa pressure, molding was completed for 900 seconds. Demolding yielded the bulletproof helmet shell.

[0038] Example 2

[0039] Using a 3D scanner, the outer surface of the MICH bulletproof helmet shell was scanned to obtain a point cloud image. Then, CATIA software was used for reverse modeling to create a 3D curved surface model 1 of the bulletproof helmet shell. Three dividing lines 2 were drawn on this 3D curved surface model, intersecting at the center point 3 of the helmet's top. The included angle between adjacent dividing lines 2 was 60°, dividing the helmet surface into 6 equal parts. The divided surface was then unfolded in two dimensions along the corresponding dividing lines 2. The central area of ​​the unfolded shape was then optimized into a circular area 4 with a radius of 60mm centered at the center point 3 of the top of the head, thus obtaining a piece shape. The dividing lines 2 were rotated 12° clockwise around the center point 3 of the top of the head, and the above operations of dividing the curve and unfolding the surface in two dimensions were repeated to obtain all the piece shapes required for the bulletproof helmet. All piece shapes were exported and numbered and laid out in CAD software.

[0040] Using a surface density of 500 g / m 2Aramid woven prepreg with a resin content of 12% was cut and numbered according to the above-mentioned pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of the bulletproof helmet, the resin-containing side of the aramid prepreg sheets was always facing down. On the male mold of the molding machine, following the shape of the helmet mold, 17 layers were sequentially laid using a butt-layup method. The pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, it was molded at 145℃ and 23MPa pressure for 900 seconds to complete the molding and curing process. Demolding yielded the bulletproof helmet shell.

[0041] Example 3

[0042] Using a 3D scanner, the outer surface of the MICH bulletproof helmet shell was scanned to obtain a point cloud image. Then, CATIA software was used for reverse modeling to create a 3D curved surface model 1 of the bulletproof helmet shell. Four dividing lines 2 were drawn on this 3D curved surface model, intersecting at the center point 3 of the helmet's top. The included angle between adjacent dividing lines 2 was 45°, dividing the helmet surface into 8 equal parts. The divided surface was then unfolded in two dimensions along the corresponding dividing lines 2. The central area of ​​the unfolded shape was then optimized into a circular area 4 with a radius of 60mm centered at the center point 3 of the top of the head, thus obtaining a piece shape. The dividing lines 2 were rotated 20° clockwise around the center point 3 of the top of the head, and the above operations of dividing the curve and unfolding the surface in two dimensions were repeated to obtain all the piece shapes required for the bulletproof helmet. All piece shapes were exported and numbered and laid out in CAD software.

[0043] Using a surface density of 350 g / m³ 2 Aramid woven prepreg with a resin content of 10% was cut and numbered according to the above-mentioned pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of the bulletproof helmet, the resin-containing side of the aramid prepreg sheets was always facing down. On the male mold of the molding machine, following the shape of the helmet mold, 24 layers were sequentially laid using a butt-layup method. Pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, at 145℃ and 23MPa pressure, molding was completed for 900 seconds. Demolding yielded the bulletproof helmet shell.

[0044] Comparative Example 1

[0045] Using a surface density of 350 g / m³ 2Aramid woven prepreg with a resin content of 10% was cut and numbered according to a traditional wind turbine-shaped pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of bulletproof helmets, the resin-containing side of each aramid prepreg sheet was always facing down. On the male mold of a molding machine, 22 layers were sequentially laid in an overlapping manner, following the shape of the helmet mold. Pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, it was molded at 145℃ and 23MPa pressure for 900 seconds to complete the molding and curing process. Demolding yielded the bulletproof helmet shell.

[0046] Comparative Example 2

[0047] Using a 3D scanner, the outer surface of the MICH bulletproof helmet shell was scanned to obtain a point cloud image. Then, CATIA software was used for reverse modeling to create a 3D curved surface model 1 of the bulletproof helmet shell. Three dividing lines 2 were drawn on this 3D curved surface model, intersecting at the center point 3 of the helmet's top. The included angle between adjacent dividing lines 2 was 60°, dividing the helmet surface into 6 equal parts. The divided surface was then unfolded in two dimensions along the corresponding dividing lines 2. The central area of ​​the unfolded shape was then optimized into a circular area 4 with a radius of 60mm centered at the center point 3 of the top of the head, thus obtaining a piece shape. The dividing lines 2 were rotated 12° clockwise around the center point 3 of the top of the head, and the above operations of dividing the curve and unfolding the surface in two dimensions were repeated to obtain all the piece shapes required for the bulletproof helmet. All piece shapes were exported and numbered and laid out in CAD software.

[0048] Using a surface density of 560 g / m³ 2 Aramid woven prepreg with a resin content of 20% was cut and numbered according to the above-mentioned pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of bulletproof helmets, the resin-containing side of the aramid prepreg sheets was always facing down. On the male mold of a molding machine, following the shape of the helmet mold, 15 layers were sequentially laid using a butt-layup method. The pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, it was molded at 145℃ and 23MPa pressure for 900 seconds to complete the molding and curing process. Demolding yielded the bulletproof helmet shell.

[0049] Comparative Example 3

[0050] Using a 3D scanner, the outer surface of the MICH bulletproof helmet shell was scanned to obtain a point cloud image. Then, CATIA software was used for reverse modeling to create a 3D curved surface model 1 of the bulletproof helmet shell. Six dividing lines 2 were drawn on this 3D curved surface model, intersecting at the center point 3 of the helmet's top. The included angle between adjacent dividing lines 2 was 30°, dividing the helmet surface into 12 equal parts. The divided surface was then unfolded in two dimensions along the corresponding dividing lines 2. The central area of ​​the unfolded shape was optimized into a circular area 4 with a radius of 60mm centered at the center point 3 of the top of the head, thus obtaining a piece shape. The dividing lines 2 were rotated 30° clockwise around the center point 3 of the top of the head, and the above operations of dividing curves and unfolding the surface in two dimensions were repeated to obtain all the piece shapes required for the bulletproof helmet. All piece shapes were exported and numbered and laid out in CAD software.

[0051] Using a surface density of 350 g / m³ 2 Aramid woven prepreg with a resin content of 10% was cut and numbered according to the above-mentioned pattern to obtain aramid prepreg sheets for each layer. Based on the areal density requirements of the bulletproof helmet, the resin-containing side of the aramid prepreg sheets was always facing down. On the male mold of the molding machine, following the shape of the helmet mold, 24 layers were sequentially laid using a butt-layup method. Pre-forming was completed at 90℃ and 10MPa pressure for 120 seconds. Then, at 145℃ and 23MPa pressure, molding was completed for 900 seconds. Demolding yielded the bulletproof helmet shell.

[0052] The bulletproof helmet shells prepared in the examples and comparative examples were tested for V50 value according to the standard GJB 5115A-2012 "Safety Technical Performance Requirements for Military Bulletproof Helmets" and for back convexity value according to the Level 2 standard GA 293-2012 "Police Bulletproof Helmets and Face Masks". The results are compared in Table 1.

[0053] Table 1

[0054]

[0055] As can be seen from the results in Table 1, the bulletproof helmet prepared by the present invention has better ballistic performance than that prepared by traditional methods. Moreover, the ballistic performance of the front, back, left, right and top parts of the helmet is almost the same, indicating that the shell of the bulletproof helmet of the present invention has a homogeneous structure.

[0056] In summary, this invention establishes a three-dimensional curved surface model of the helmet shell based on its shape, divides the curved surface with dividing lines, and unfolds it into a piece shape. The central area of ​​the piece forms an undivided area, which avoids wrinkles caused by the piece shape not fitting the helmet shape, while ensuring the ballistic performance of the helmet top. This invention lays multiple pieces formed by dividing lines at different angles in sequence on the helmet mold using a butt joint method, pre-forming them, and finally molding and curing them. The butt joint method avoids the phenomenon of material piling up at the lower edge of the helmet caused by overlapping pieces, further improving the overall uniformity of the bulletproof helmet, thereby improving the overall ballistic performance of the bulletproof helmet.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a homogeneous bulletproof helmet shell, characterized in that, Includes the following steps: S1. Perform a three-dimensional scan of the outer surface of the helmet shell to establish a three-dimensional curved surface model of the helmet shell; S2. Draw several dividing lines on the three-dimensional curved surface model. The dividing lines intersect at the center point of the top of the helmet, dividing the helmet surface into several equal parts. S3. Unfold the segmented curved surface along the corresponding dividing lines in a two-dimensional plane, leaving the top area unsegmented, to obtain a piece shape. S4. Rotate the dividing line around the center point of the top of the head at different angles in sequence, and repeat the above steps S2-S3 to obtain several piece shapes. S5. Cut the prepreg into multiple pieces, lay the multiple pieces on the helmet mold in sequence by joining them together, pre-form, and then mold and cure to obtain the helmet shell.

2. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, Step S1 includes: using a 3D scanner to perform a 3D scan on the outer surface of the helmet shell to obtain a point cloud map, and then using software to reverse model and establish a 3D curved surface model of the helmet shell.

3. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, In step S2, the helmet surface is divided into 4 to 8 equal parts.

4. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, Step S3 includes: unfolding the segmented curved surface along the corresponding dividing lines in a two-dimensional plane, and then forming a circular area with the center point of the top of the head as the center of the central region of the unfolded graphic to obtain a piece shape.

5. The method for preparing a homogeneous bulletproof helmet shell according to claim 4, characterized in that, The radius of the circular region is 50-70mm.

6. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, In step S4, the angle is 10-25°.

7. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, In step S5, the prepreg is an aramid woven prepreg, which is coated with phenolic resin on one side and has an areal density of 200-500 g / m³. 2 The mass percentage of phenolic resin in these samples is between 8% and 15%.

8. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, In step S5, the preforming temperature is 90±3℃, the pressure is 10±1MPa, and the time is 120±5s.

9. The method for preparing a homogeneous bulletproof helmet shell according to claim 1, characterized in that, The molding and curing temperature is 145±3℃, the pressure is 23±1MPa, and the time is 900±5s.

10. A homogeneous bulletproof helmet shell, characterized in that, The homogeneous bulletproof helmet shell is prepared using the method described in any one of claims 1-9.

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