Split type bulletproof helmet bullet mark height measuring device

Abstract

The utility model belongs to the field of end point ballistic experiments, and relates to a split type bulletproof helmet bullet mark height measuring device which is composed of a plurality of curved surface clamping plates, each curved surface clamping plate is of an inwards-concave structure, the shape of each curved surface clamping plate is matched with the corresponding position of a bulletproof helmet to be measured, and each curved surface clamping plate comprises an annular edge face, an inwards-concave face and an outwards-convex face. The shape of the annular edge surface is tightly fit and matched with the corresponding position of the outer surface of the bulletproof helmet; the curved-surface clamping plate comprises a helmet top curved-surface clamping plate, a helmet front curved-surface clamping plate, a helmet rear curved-surface clamping plate, a helmet left curved-surface clamping plate and a helmet right curved-surface clamping plate which correspond to the helmet top part, the helmet front part, the helmet rear part, the helmet left part and the helmet right part of the bulletproof helmet to be detected respectively. When the device is used for testing, the problem that the bullet mark height of the bulletproof helmet cannot be accurately measured due to the fact that a measuring datum point on the outer side of the helmet shell is lost after the bulletproof helmet is shot is solved; meanwhile, the design of the split-type curved-surface clamping plate enables the measurement operation to be simpler, more convenient and more flexible, and the test efficiency is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the field of terminal ballistic experiments and relates to a fragmented bulletproof helmet bullet mark height measuring device. Background Art

[0002] In the field of human protection, bulletproof helmets are important equipment for human protection, and their anti-ballistic performance is directly related to the life safety of combatants. The bullet mark height after a bullet impact refers to the residual deformation height of the bulletproof helmet after a bullet impact. This indicator is a key parameter for evaluating the anti-ballistic performance of a bulletproof helmet. Existing bulletproof helmets generally need to measure the bullet mark height at different positions of the helmet, such as the top of the helmet, the front of the helmet, the back of the helmet, the left of the helmet, and the right of the helmet. GA 293-2012 Police Bulletproof Helmets and Masks stipulates that the bullet mark height should be less than or equal to 25mm, so accurate measurement of the bullet mark height is an important prerequisite for judging whether a bulletproof helmet is qualified.

[0003] For the measurement of residual deformation, when the outer side of the helmet is not deformed, the total thickness of the helmet after the bullet impact can be measured by subtracting the total thickness of the inner and outer sides of the helmet shell before the bullet impact. However, whether it is a helmet made of metal or non-metal composite materials, bullet holes, depressions or reverse bulges will be formed on the surface of the helmet shell after the bullet impact, resulting in the loss of the measurement reference point on the outer side of the helmet shell, making it difficult to accurately measure the total thickness of the helmet after the bullet impact and the height of the bullet mark.

[0004] CN 103907007 A discloses a device and method for measuring the back indentation of a bulletproof plate, the device includes a deformable backing medium, the deformable backing medium has a front surface; a spacer, the spacer defines a space adjacent to the deformable backing medium, the spacer separates the fiber material positioned adjacent to the deformable backing medium from the front surface of the deformable backing medium; and at least one support member, the support member is used to support the fiber material in a position adjacent to the front surface of the deformable backing medium, and also discloses a method for evaluating the back indentation of the fiber material using the device, and the patent provides that the maximum instantaneous deformation of the bullet-proof plate can be recorded by measuring the indentation of the bullet-proof plate on the backing medium as the back indentation during the bullet-proof plate. However, composite bulletproof plates usually have the characteristics of elastic recovery, that is, the bullet-proof plate will gradually decrease after the maximum instantaneous deformation is formed and form a permanent deformation (bullet mark height). Therefore, the maximum instantaneous deformation caused by the bullet is different from the bullet mark height, and the former is usually greater than the latter. The method disclosed in CN103907007A can measure the maximum instantaneous deformation of a bullet impact, but cannot measure the bullet mark height. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, the utility model provides a piece-type bullet-proof helmet bullet hole height measurement tool, which can effectively avoid the influence of adverse factors such as bullet holes, depressions and reverse bulges after bullet impact, improve the accuracy of helmet bullet hole height measurement, and enhance the reliability of the bullet-proof performance judgment criterion of the bullet-proof helmet.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] A sliced ​​bulletproof helmet bullet mark height measuring device is composed of a plurality of curved surface card plates, wherein the curved surface card plates are concave structures, and their shapes match the corresponding positions of the bulletproof helmet to be tested, and include an annular edge surface, an inner concave surface, and an outer convex surface, and the shape of the annular edge surface closely matches the corresponding positions of the outer surface of the bulletproof helmet; the curved surface card plates include a helmet top curved surface card plate, a helmet front curved surface card plate, a helmet rear curved surface card plate, a helmet left curved surface card plate, and a helmet right curved surface card plate, which respectively correspond to the helmet top, helmet front, helmet rear, helmet left, and helmet right parts of the bulletproof helmet to be tested.

[0008] The curved surface card board is made of rigid metal material to meet the structural rigidity and ensure that the curved surface card board does not deform. Preferably, the height difference between the inner concave surface and the outer convex surface of the curved surface card board is not less than 6mm.

[0009] The inner concave surface is fitted with a gap between the bulletproof helmet to be tested, and the gap distance can be designed according to the height of the reverse deformation of the bulletproof helmet; the purpose of the gap fit is to reserve space for the reverse deformation of the material around the bullet hole, so as to ensure that the ring edge surface is closely fitted with the surface of the bulletproof helmet to be tested.

[0010] The curved surface pallet is processed by CNC processing method, and the specific processing method is as follows:

[0011] Firstly, a 3D model of the helmet is established according to the spline curve of the helmet model size by using 3D software or 3D scanning technology; then, based on the 3D model of the helmet, a 3D model of the curved pallet is constructed by using 3D graphics processing means; finally, the curved pallet is manufactured by using a CNC machining method according to the 3D model of the curved pallet.

[0012] The measuring device is used as follows:

[0013] Before the bullet impact test, the edge of the curved surface card plate is tightly fitted with the corresponding outer surface of the bulletproof helmet, and a marker is used to mark the outer surface of the bulletproof helmet along the fitting line between the curved surface card plate and the bulletproof helmet; the total thickness of the curved surface card plate and the bulletproof helmet is measured with an external caliper gauge, which is recorded as t0;

[0014] Conduct bullet impact tests on bulletproof helmets according to the bullet impact sequence required by the test standard;

[0015] After the bullet impact test is completed, the curved surface cardboard is fitted to the outer surface of the bulletproof helmet according to the mark, and the total thickness of the curved surface cardboard and the maximum deformation height of the inner surface of the bulletproof helmet is measured with an external caliper, which is recorded as t1;

[0016] Calculate the total thickness difference of different parts before and after the bullet impact test. The total thickness difference of different parts is the bullet mark height of different parts of the bulletproof helmet, that is, the permanent deformation TH, TH = t1-t0.

[0017] The measuring tool of the utility model solves the problem that the measuring reference point on the outer side of the helmet shell is missing after the bulletproof helmet is hit by a bullet, and the height of the bullet mark cannot be accurately measured; the split curved surface card plate design makes the measuring operation simpler and more flexible, and effectively improves the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a three-dimensional structural diagram of the split curved surface card board involved in the utility model

[0019] Figure 2 yes Figure 1 Main view

[0020] Figure 3 yes Figure 1 Top view

[0021] Figure 4 yes Figure 1 Right view

[0022] Figure 5 This is a schematic diagram of the three-dimensional structure of the curved surface cardboard behind the helmet involved in the utility model.

[0023] Figure 6 This is a schematic diagram of the existing technology for measuring the height of the bullet hole on the left side of the helmet

[0024] Figure 7 This is a schematic diagram of measuring the height of the bullet mark on the left side of the helmet involved in the utility model

[0025] Figure 8 Comparison of bullet hole height values ​​measured by the prior art and the utility model

[0026] Among them, 1. the curved surface pallet of the top of the helmet; 2. the curved surface pallet of the front of the helmet; 3. the curved surface pallet of the back of the helmet; 4. the curved surface pallet of the left side of the helmet; 5. the curved surface pallet of the right side of the helmet; 6. the ring edge surface; 7. the inner concave surface; 8. the outer convex surface; 9. the helmet shell; 10. the outer surface of the helmet shell before the impact; 11. the distance between the starting position of the outer surface of the helmet shell before the impact and the inner surface of the helmet shell after the impact; 12. the distance between the outer surface and the inner surface of the helmet shell after the impact; 13. the distance between the outer surface of the curved surface pallet and the inner surface of the helmet shell after the impact. DETAILED DESCRIPTION

[0027] The utility model is further described below in conjunction with the accompanying drawings and embodiments. The structures, proportions, sizes, etc. illustrated in the accompanying drawings of this specification are only used to match the contents disclosed in the specification, so that people familiar with this technology can understand and read them, and are not used to limit the limiting conditions that can be implemented in the utility model, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in the utility model without affecting the effects that can be produced by the utility model and the purposes that can be achieved. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are also only for the convenience of narration, and are not used to limit the scope that can be implemented in the utility model. The change or adjustment of its relative relationship should also be regarded as the scope that can be implemented in the utility model without substantially changing the technical content.

[0028] The ballistic performance test of the bulletproof helmet was carried out in accordance with the Level 2 protection requirements of the police bulletproof helmet standard GA 293-2012. The test bullets were 1954-style 7.62mm pistol and 1954-style 7.62mm pistol bullets, and the bullet impact positions were the top, front, back, left and right of the helmet.

[0029] Example 1

[0030] A piece-type bulletproof helmet bullet hole height measurement tool, composed of a helmet top curved surface card plate, a helmet front curved surface card plate, a helmet back curved surface card plate, a helmet left curved surface card plate and a helmet right curved surface card plate, which correspond to the top, front, back, left and right parts of the bulletproof helmet respectively. The curved surface card plate is a concave structure, and its shape matches the corresponding position of the bulletproof helmet, including a ring edge surface, an inner concave surface and an outer convex surface, and the structure is as follows Figure 1-4 shown.

[0031] The curved pallet is made of aluminum material, and other rigid metal materials can also be used. The height difference between the curved pallet ring edge and the inner concave surface is 4mm, and the height difference between the inner concave surface and the outer convex surface is 6mm.

[0032] Before the test, fit the curved cardboard to the outer surface of the bulletproof helmet, and fit the edge surface to the bulletproof helmet tightly. Use a marker to mark the outer surface of the bulletproof helmet along the fitting line between the curved cardboard and the bulletproof helmet.

[0033] Use an external caliper gauge to measure the total thickness of the curved surface plate and the bulletproof helmet. The total thickness of the top, front, back, left and right parts of the helmet are recorded as t c0 ,t f0 ,t b0 ,t l0 ,t r0 .

[0034] The bullet-proof helmet is tested for bullet impact according to the bullet impact sequence required by the standard.

[0035] After the bullet impact test is completed, the edge of the curved card plate is tightly fitted to the outer surface of the bulletproof helmet. The total thickness of the curved card plate and the maximum deformation height of the inner concave surface of the bulletproof helmet is measured using an external caliper. The total thickness of the top, front, back, left and right parts of the helmet are recorded as t c1 ,t f1 ,t b1 ,t l1 ,t r1 .

[0036] The bullet hole heights of different parts of the bulletproof helmet are calculated according to the total thickness before and after the bullet impact test. The bullet hole heights of the top, front, back, left and right parts of the helmet are TH and TH, respectively. c =t c1 -t c0 , TH f =t f1 -t f0 , TH b =t b1 -t b0 , TH l =t l1 -t l0 , TH r =t r1 -t r0 .

[0037] The test results of the prior art solution and the technical solution of the utility model are measured and compared. Figure 6 , the schematic diagram of bullet mark height measurement of the utility model technical solution is shown in Figure 7 .

[0038] To avoid the influence of human operation, the two technical solutions were implemented by the same test personnel. The test personnel used the two technical solutions to measure three times at each impact position. The measurement results are shown in Table 1. Based on the measurement results in Table 1, Figure 8 A comparison chart of the measurement results of the prior art solution and the technical solution of this patent is given, and it can be clearly seen that: on the one hand, the measurement results of the technical solution of the present invention are consistent, while the measurement results of the prior art solution are highly dispersed; in addition, from the numerical value of the bullet mark height, the measurement results of the technical solution of the present invention are generally higher than those of the prior art solution. This is because the surface of the helmet shell is concave after the bullet hit, and the measurement surface of the prior art solution is lower than the original reference surface position of the helmet shell, resulting in a smaller measurement result. The smaller bullet mark height measurement result of the prior art solution will lead to an overestimation of its anti-ballistic performance, resulting in unreliable helmet performance evaluation.

[0039] Table 1 Bullet mark height measurement results of two technical solutions

[0040]

[0041] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A device for measuring bullet hole height of a segmented bulletproof helmet, characterized in that: It is composed of several curved surface card plates, which are concave structures, and their shapes match the corresponding positions of the bulletproof helmets, including ring edge surfaces, inner concave surfaces and outer convex surfaces; the shape of the ring edge surfaces closely matches the corresponding positions of the outer surfaces of the bulletproof helmets; the curved surface card plates include the top curved surface card plate, the front curved surface card plate, the rear curved surface card plate, the left curved surface card plate and the right curved surface card plate, which correspond to the top, front, rear, left and right parts of the bulletproof helmets respectively.

2. The device for measuring bullet hole height of a segmented bulletproof helmet according to claim 1, characterized in that: The height difference between the inner concave surface and the outer convex surface of the curved card plate is not less than 6mm.

3. The bullet-mark height measuring device for a segmented bulletproof helmet according to claim 1 or 2, characterized in that: The inner concave surface is in gap fit with the bulletproof helmet to be tested.

4. The bullet-mark height measuring device for a segmented bulletproof helmet according to claim 1 or 2, characterized in that: The curved surface clamping plate is made of rigid metal material.

5. The device for measuring bullet hole height of a segmented bulletproof helmet according to claim 1, characterized in that: The curved surface pallet is constructed by using 3D graphics processing means to construct a 3D model of the curved surface pallet, and then is processed by using a numerical control processing method.

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