Bulletproof radome with reduced instantaneous sag and method of forming same

Abstract

The application discloses a bulletproof radome with reduced instantaneous depression and a forming method thereof, and belongs to the technical field of military antenna protective covers. The forming method comprises the following steps: adopting aramid fiber as a reinforcing base composite material as a cover body of the bulletproof radome, pre-pressing forming through a mold pressing process to obtain a pre-pressed part; placing the pre-pressed part in a punching tool and then placing the pre-pressed part in a hydraulic machine, adjusting to a set pressure to perform spiral punching to obtain a punched cover body; placing the punched cover body in a sewing device to perform spiral sewing treatment to obtain a spiral sewn cover body; and performing mold pressing curing on the spiral sewn cover body to obtain the bulletproof radome with reduced instantaneous depression. The sewing lines on the prepared bulletproof radome are arranged in a spiral shape, and the line distance between the sewing lines is 10mm-25mm.

Description

Technical Field

[0001] This invention belongs to the field of military antenna protective cover technology, specifically relating to a bulletproof antenna cover that reduces instantaneous indentation and its molding method. Background Technology

[0002] Existing bulletproof radomes are manufactured using traditional molding processes. However, due to the inherent high elongation at break of aramid fibers, during firing, the fibers deform under tensile force as the bullet penetrates them, resulting in bulges on the bullet-backed surface of the composite material. The high elongation at break of aramid composites leads to significant instantaneous deformation upon bullet penetration. If the distance between the radome and the antenna is limited, this deformation could damage the antenna. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a bulletproof antenna radome with reduced instantaneous indentation and its molding method. In view of the limited distance between the bulletproof antenna radome and the antenna, a specific spiral stitching process is used to reduce the deformation of the material. When the fiber material is deformed, the instantaneous indentation value during the bullet penetration process is reduced, thus avoiding damage to the internal antenna.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention provides a method for molding a bulletproof antenna radome that reduces instantaneous dents, comprising the following steps:

[0006] A composite material with aramid fiber as the reinforcing matrix is ​​used as the cover of the bulletproof antenna radome. It is pre-pressed by molding process to obtain a pre-pressed part. The pre-pressed part is placed in a punching fixture and then placed in a hydraulic press. The pressure is adjusted to the set point to perform spiral punching to obtain a punched radome. The punched radome is placed in a sewing device and spirally sewn to obtain a spirally sewn radome. The spirally sewn radome is then molded and cured to obtain a bulletproof antenna radome with reduced instantaneous dents.

[0007] In the specific implementation process, the temperature of the pre-compression molding is 60-70℃, and the pressure of the pre-compression molding is 7-10MPa.

[0008] In the specific implementation process, the punching tool consists of a punching base plate and a punching needle, with the punching needle embedded in the punching base plate.

[0009] In the specific implementation process, the set pressure is 7-10MPa; the diameter of the hole of the spiral drilling is 1mm-2mm; and the distance between two adjacent holes of the spiral drilling is 10mm-25mm.

[0010] In the specific implementation process, the diameter of the suture thread in the spiral suturing process is 0.5mm-1.5mm.

[0011] In the specific implementation process, the pressure for molding and curing is adjusted to 15-25 MPa, the temperature for molding and curing is adjusted to 150-200℃, and the curing time for molding and curing is 30-60 min.

[0012] The present invention provides a bulletproof antenna radome manufactured by the molding method for reducing instantaneous indentation according to any one of the claims.

[0013] In the specific implementation process, the stitching lines on the bulletproof antenna cover are arranged in a spiral shape, and the spacing between the stitching lines is 10mm-25mm.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This invention provides a molding method for a bulletproof radome that reduces instantaneous indentation. The inventive aspect lies in employing a stitching process where yarns in the z-axis direction interweave along the thickness direction of the composite material, bonding adjacent yarns together. The cured resin matrix further assists in fixing the yarns, thereby achieving structural integrity in the thickness-coated composite material, making it more stable and less prone to delamination. A further inventive aspect is the use of specific spiral perforation and spiral stitching to address the problem that stress propagation in the stitched composite material is faster in the z-axis reinforcing fiber but relatively slower in the resin. This results in stress waves that are less likely to reach the maximum destructive stress of the high-performance fibers but more likely to reach the maximum destructive stress of the resin, causing the damage area of ​​the resin around the bullet hole to be larger than the damage area of ​​the reinforcing high-performance fibers.

[0016] The present invention also provides a bulletproof antenna radome made based on the above method, which has spirally arranged stitching lines, so that during the deformation process of the fiber material, the directional force in the z-axis direction restricts the deformation of the fiber material, reduces the material deformation, and reduces the instantaneous indentation value during bullet penetration. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the punching fixture structure in the forming method of the bulletproof antenna radome for reducing instantaneous indentation according to the present invention.

[0018] Figure 2 This is a schematic diagram of the spiral stitching process in the forming method of the bulletproof antenna radome for reducing instantaneous dents according to the present invention.

[0019] Among them: 1-Drilling base plate; 2-Drilling pin; 3-Auxiliary tooling; 4-Pre-compression part. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0022] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] This invention provides a bulletproof antenna radome that reduces instantaneous dents and its molding method.

[0026] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0027] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0028] One aspect of the present invention provides a method for molding a bulletproof radome that reduces momentary dents, comprising the following steps:

[0029] S1: A composite material with aramid fiber as the reinforcing matrix is ​​used as the cover of the bulletproof antenna radome. The material is lightweight, high-strength, and has excellent wave transmission performance, so that the antenna radome can resist a certain bullet penetration while meeting the wave transmission requirements. It is formed by molding process, specifically pre-pressed at 60-70℃ and 7-10MPa to obtain pre-pressed part 4.

[0030] S2: As Figure 1 As shown, the pre-compressed part 4 is placed in the punching fixture consisting of the hole base plate 1 and the punching needle 2, and then placed in the hydraulic press. The pressure is adjusted to 7-10MPa for spiral punching to obtain the punched cover. Specifically, the punching needle 2 is embedded in the punching base plate 1. The diameter of the hole for spiral punching is 1mm-2mm, the distance between two adjacent holes for spiral punching is 10mm-25mm, and the spiral line spacing for spiral punching is 10mm-25mm.

[0031] In the specific implementation process, a drilling fixture and an auxiliary fixture 3 are used in the drilling process. The drilling fixture consists of a hole base plate 1 and a drilling needle 2. The drilling needle 2 is embedded in the hole base plate 1, which is made of metal. The auxiliary fixture 3 is a hard wooden block. The drilling is completed by opening and closing the hydraulic press once.

[0032] S3: Place the perforated cover in a specific sewing device, such as Figure 2 As shown, a spiral suture process is performed to obtain a spiral sutured cover; specifically, the suture diameter is 0.5mm-1.5mm.

[0033] S4: The spiral stitched radome is molded and cured under the conditions of 15-25MPa adjustable pressure, 150-200℃ adjustable temperature and 30-60min curing time. The stitched product is molded and formed to complete the product preparation and obtain a bulletproof antenna radome with reduced instantaneous dents.

[0034] Another aspect of the present invention provides a bulletproof antenna radome with reduced instantaneous indentation prepared based on the above method. The stitches on the radome are arranged in a spiral shape, and the spacing between the stitches is 10mm-25mm. The special spiral arrangement of the stitching process reduces the deformation of the material. When the fiber material deforms, the instantaneous indentation value during the bullet penetration process is reduced, thus avoiding damage to the internal antenna.

[0035] Example 1

[0036] A composite material reinforced with aramid fiber was used as the cover of the bulletproof antenna radome. The radome was pre-pressed at 60℃ and 7MPa to obtain a pre-pressed part 4. The pre-pressed part 4 was then placed in a punching fixture and placed in a hydraulic press. Under a set pressure of 7MPa, spiral punching was performed with a spacing of 10mm between two adjacent holes to obtain a punched radome. The punched radome was then placed in a sewing machine using 0.5mm diameter thread for spiral sewing to obtain a spirally sewn radome. Finally, the spirally sewn radome was molded and cured under a set pressure of 15MPa, a set temperature of 150℃, and a curing time of 30 minutes to obtain a bulletproof antenna radome with a 10mm spacing between the stitches, reducing instantaneous indentation.

[0037] Example 2

[0038] A composite material reinforced with aramid fiber was used as the cover of the bulletproof antenna radome. It was pre-pressed at 70℃ and 10MPa to obtain a pre-pressed part 4. The pre-pressed part 4 was then placed in a punching fixture and placed in a hydraulic press. Under a set pressure of 10MPa, spiral punching was performed with a spacing of 25mm between two adjacent holes to obtain a punched radome. The punched radome was then placed in a sewing machine using 1.5mm diameter thread for spiral sewing to obtain a spiral-sewn radome. The spiral-sewn radome was then molded and cured under an adjusted pressure of 25MPa, an adjusted temperature of 200℃, and a curing time of 60 minutes to obtain a bulletproof antenna radome with a 25mm spacing between the stitches, reducing instantaneous indentation.

[0039] Example 3

[0040] A composite material reinforced with aramid fiber was used as the cover of the bulletproof antenna radome. The radome was pre-pressed at 65℃ and 8MPa to obtain a pre-pressed part 4. The pre-pressed part 4 was then placed in a punching fixture and placed in a hydraulic press. A spiral punching process with a 20mm spacing between two adjacent holes was performed at a set pressure of 7MPa to obtain a punched radome. The punched radome was then placed in a sewing machine using 1.0mm diameter thread for spiral sewing to obtain a spiral-sewn radome. The spiral-sewn radome was then molded and cured at an adjusted pressure of 20MPa, an adjusted temperature of 180℃, and a curing time of 50 minutes to obtain a bulletproof antenna radome with a 20mm spacing between the stitches, reducing instantaneous indentation.

[0041] Example 4

[0042] A composite material reinforced with aramid fiber was used as the cover of the bulletproof antenna radome. The radome was pre-pressed at 67.5℃ and 9MPa to obtain a pre-pressed part 4. The pre-pressed part 4 was then placed in a punching fixture and placed in a hydraulic press. A spiral punching process with a 22mm spacing between two adjacent holes was performed at a set pressure of 10MPa to obtain a punched radome. The punched radome was then placed in a sewing machine and 1.25mm diameter thread was used for spiral sewing to obtain a spiral-sewn radome. The spiral-sewn radome was then molded and cured at an adjusted pressure of 10MPa, an adjusted temperature of 200℃, and a curing time of 30 minutes to obtain a bulletproof antenna radome with a 22mm spacing between the stitches, reducing instantaneous indentation.

[0043] Instantaneous dent test

[0044] Table 1

[0045]

[0046] According to the test methods in GJB4300A-2012 "Safety Technical Performance Requirements for Military Bulletproof Vests", the bulletproof plate was subjected to a bulletproof performance test. The protection level was 2 (at room temperature, with a 7.62mm lead-core bullet from a Type 51 pistol, V0 > 455m / s, and an incident angle of 0°). The results are shown in the comparison table above of the instantaneous indentation test of unstitched and stitched bulletproof antenna covers of the same thickness. Under the same thickness, the instantaneous indentation of the stitched bulletproof antenna cover was reduced by 5mm-10mm compared with the antenna cover prepared by conventional process.

[0047] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for molding a bulletproof radome to reduce instantaneous dents, characterized in that, Includes the following steps: A composite material with aramid fiber as the reinforcing matrix is ​​used as the cover of the bulletproof antenna radome. It is pre-pressed by molding process to obtain a pre-pressed part (4). The pre-pressed part (4) is placed in a punching fixture and then placed in a hydraulic press. The pressure is adjusted to the set point to perform spiral punching to obtain a punched cover. The punched cover is placed in a sewing device and spiral sewing is performed. The sewing line in the z-axis direction is intersected in the thickness direction of the punched cover to obtain a spiral sewn cover. The spiral sewn cover is molded and cured to obtain a bulletproof antenna radome with reduced instantaneous indentation. The stitching on the bulletproof antenna radome is arranged in a spiral pattern, with a spacing of 10mm-25mm between the stitches.

2. The molding method for reducing instantaneous dents of the bulletproof radome according to claim 1, characterized in that, The pre-compression molding temperature is 60-70℃, and the pre-compression molding pressure is 7-10MPa.

3. The molding method for reducing instantaneous dents of the bulletproof radome according to claim 1, characterized in that, The punching fixture consists of a punching base plate (1) and a punching needle (2), with the punching needle (2) embedded in the punching base plate (1).

4. The molding method for reducing instantaneous dents of the bulletproof radome according to claim 1, characterized in that, The set pressure is 7-10 MPa; the diameter of the hole in the spiral drilling is 1 mm-2 mm; the distance between two adjacent holes in the spiral drilling is 10 mm-25 mm.

5. The molding method for reducing instantaneous dents of a bulletproof radome according to claim 1, characterized in that, The diameter of the suture thread in the spiral suturing process is 0.5mm-1.5mm.

6. The molding method for reducing instantaneous dents of a bulletproof radome according to claim 1, characterized in that, The pressure for molding and curing is 15-25 MPa, the temperature for molding and curing is 150-200℃, and the curing time for molding and curing is 30-60 min.

7. A bulletproof radome manufactured by the molding method for reducing instantaneous dents according to any one of claims 1 to 6.

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