Fragment mass distribution test device and evaluation method based on fragment perforation contour image

Abstract

The invention provides a fragment mass distribution test device and evaluation method based on a fragment perforation contour image, and the method comprises the steps: obtaining a perforation image of a fragment through a thin sampling plate, obtaining the quality of each fragment through an image processing analysis technology, and obtaining the corresponding fragment mass distribution. The defect that the damage power can only be judged through the number of through holes in the prior art is overcome. According to the method, the complexity of the previous test is reduced to a great extent by utilizing an image processing technology mainly aiming at the mass distribution condition of the fragments integrally formed by the explosion-killing warhead; meanwhile, a novel spatial distribution test can be designed according to actual requirements, the quality and number characteristics of fragments formed in different scattering areas are obtained through the image processing technology, and the problem that only the number can be obtained in the past can be solved.

Description

Technical Field

[0001] The invention relates to a method for characterizing the mass of fragments during the explosion of a blast warhead, and specifically proposes a fragment mass distribution test device and an evaluation method based on a fragment perforation profile image. Background Art

[0002] The warhead will generate high-speed fragments under the loading of internal explosives. Until today, using fragments to kill people has been one of the main ways of damage on the battlefield. In the experimental research on the characteristics and distribution of fragments, it is often only possible to analyze them through warhead explosion fragmentation recovery tests and spatial distribution tests. The warhead explosion fragmentation characteristics can only be obtained by manually counting the mass of all fragments and the number of fragments on the pine wood target. The previous experimental methods are relatively complicated to operate. In addition, the spherical target or fan-shaped target often used in the description of the spatial distribution test of warhead explosion fragmentation cannot reflect the different mass characteristics of fragments formed by the warhead at each dispersion angle, because it is assumed that the average mass of fragments in each dispersion area is consistent, which is inconsistent with the actual fragmentation process.

[0003] Reference 1: Klopcic J T. An efficient technique for the collection and analysis of fragment mass distributions from fragmenting munitions [R]. Aberdeen Proving Ground, USA Army Research Laboratory, 1996. The article studies the recovery technology of fragments formed by warhead fragmentation, and uses soft material haystacks to recover the formed fragments. However, this method requires a large amount of hardware equipment required for real-time observation and real-time data processing, which brings many inconveniences to the experiment.

[0004] Reference 2 Li Junhua, Dang Shuangxi. Analysis and research on the test method of spatial density distribution of projectile fragments [J]. Journal of Projectiles, Rockets and Guidance, 1992, 12(2): 61-72. The paper proposes that the density distribution law of fragments generated after projectile explosion in different spatial dispersion directions is an important parameter for evaluating projectile structure and assessing projectile lethality. A relatively complete new test method for measuring the spatial density distribution law of fragments is designed. However, the differences in the mass characteristics of fragments formed at different dispersion angles are not obtained, and only the differences in the number of fragments formed in different dispersion areas are considered.

[0005] Therefore, there is an urgent need to provide an efficient, convenient, accurate and reliable method for evaluating fragment mass distribution. Summary of the invention

[0006] Based on the problems existing in the above-mentioned prior art, the present invention proposes a fragment mass distribution test device and evaluation method based on fragment perforation contour image. The method first obtains the perforation image of the fragment through a thin sampling plate, and then uses image processing and analysis technology to obtain the mass of each fragment, and then obtains the corresponding fragment mass distribution, which solves the deficiency that the destructive power can only be determined by the number of perforations in the past.

[0007] The present invention provides a fragment mass distribution test device based on fragment perforation contour image, comprising a test sample, an aluminum alloy thin plate, and a recovery box; the aluminum alloy thin plate is used to analyze the fragment perforation shape; the recovery box is used to recover the fragments formed after the test sample explodes.

[0008] Specifically, the test sample is a metal shell, which is placed horizontally 1m from the ground. Aluminum alloy sheets with a length of 2.5m, a width of 1.5m and a thickness of 2mm are placed on both sides, which are mainly used to analyze the perforation shape of fragments. The center of the shell and the center of the aluminum plate are on the same horizontal plane. A recycling box with the same length and width and a depth of 0.5m is placed behind the aluminum plates on both sides. The recycling box is filled with fine sand, and the fragments are recovered using sand box recovery technology. The recovered fragments are then weighed and grouped to obtain their mass distribution law.

[0009] The present invention also provides a fragment mass distribution assessment method based on fragment perforation contour images, which uses computer vision detection technology and multi-level grayscale segmentation technology to automatically obtain all fragment perforation contour sizes, and then obtains fragment mass distribution results through conversion relationships.

[0010] Compared with the prior art, the present invention has the following obvious advantages:

[0011] 1. The present invention mainly focuses on the mass distribution of fragments formed by the overall explosive warhead, and makes use of image processing technology to a large extent to reduce the complexity of previous experiments.

[0012] 2. According to actual requirements, a new type of spatial distribution test can be designed, and image processing technology can be used to obtain the quality and quantity characteristics of fragments formed in different flying areas, which can solve the problem of only being able to obtain quantity in the past.

[0013] 3. The method is simple, the test cost is low, it is easy to apply in practice, and it provides technical support for the design of warhead destructive power. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 : Experimental arrangement diagram of the present invention;

[0016] Figure 2 : Test site diagram of the present invention;

[0017] Figure 3 : A single test fragment recovery result diagram of the present invention;

[0018] Figure 4 : A diagram showing the distribution of fragment holes on one side of the target plate in a single test of the present invention;

[0019] Figure 5 : A diagram of the hole contour image processing steps of the present invention. DETAILED DESCRIPTION

[0020] The following descriptions of the embodiments are made with reference to the attached drawings to illustrate specific embodiments in which the present invention may be implemented. The directional terms mentioned in the present invention, such as [up], [down], [front], [back], [left], [right], [inside], [outside], [side], etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, but not to limit the present invention. In the drawings, units with similar structures are represented by the same reference numerals.

[0021] Embodiment 1:

[0022] like Figure 1 , 2 As shown, this embodiment provides a fragment mass distribution test device based on fragment perforation contour image, including a test sample, an aluminum alloy thin plate, and a recovery box; the aluminum alloy thin plate is used to analyze the fragment perforation shape; the recovery box is used to recover the fragments formed after the test sample explodes.

[0023] Specifically, the test sample is a metal shell and is placed horizontally 1 meter above the ground.

[0024] Specifically, the aluminum alloy thin plates are placed on both sides of the metal shell, and the center of the metal shell and the center of the aluminum plate are on the same horizontal plane.

[0025] Specifically, the aluminum alloy thin plate is 2.5 m long, 1.5 m wide, and 2 mm thick.

[0026] Specifically, there are two recycling boxes, which are placed behind the aluminum alloy sheets on both sides respectively.

[0027] Specifically, the recycling box has equal length and width, and a depth of 0.5m.

[0028] During the test, the recovery box was filled with fine sand, and the fragments were recovered using sandbox recovery technology. The recovered fragments were then weighed and grouped to obtain their mass distribution pattern.

[0029] In addition, in the metal shell explosion fragmentation fragment recovery test, the properties of the deceleration medium and the thickness of the deceleration medium layer directly affect the accuracy and reliability of the test. This test uses very fine and soft white sand as the deceleration medium to minimize the possibility of secondary collision and crushing of high-speed fragments. The fragments are recovered using three processes: air blowing, screen filtering and magnet suction to ensure a high recovery rate of fragments.

[0030] Furthermore, in consideration of the operability of the experiment, the present invention adopts a method of partial recovery of the fragments formed by the shell explosion. Since the internal explosive and the metal shell are a completely axisymmetric structure, the probability of the number of fragments flying circumferentially from the shell under the center endpoint detonation is the same, so partial recovery can be used instead of complete recovery.

[0031] Depend on Figure 1 It can be seen that the fragment recovery angle θ = 2*2×arctan -1 (0.75 / 1.5)=106.26°.

[0032] Specifically, the number of repetitive tests of the present invention is two. Theoretically, the mass of the fragments recovered from the test should be: 2*745.76*106.26° / 360°=440.24g.

[0033] Furthermore, after the test, the shell fragments formed by the explosion condition were recovered by filtering with a multi-layer nylon screen with a mesh size of 0.1×0.1 mm and picking up with a magnet. Figure 3 As shown in the figure, it can be seen that the shape of the fragments is very irregular, but basically long and narrow, and the aspect ratio of the fragments is mostly greater than 1.5.

[0034] Embodiment 2:

[0035] After the test, the aluminum plate is as follows Figure 4 As shown in the figure, due to the large size of the aluminum plate and the influence of light, some holes are not obvious, but it can be seen from the figure that the size of the fragment holes is the largest in the middle and the smallest on both sides. This is related to the rarefaction wave effect at the detonation point and the two ends. In actual crack propagation, the axial strain of the shell from the detonation end to the non-detonation end is not consistent, and the axial tensile strain of the shell has a gradient along the axial direction. The initial axial change of the middle section fragment is relatively slow, and the axial strain rate is also small, so it is easier to form larger fragments. The speed changes faster at the two ends, and the relative speed between each microelement is large, which makes it easier to cause axial fracture, and the size of the fragments formed is smaller.

[0036] Under explosion conditions, the metal shell is broken into fragments, which will fly around at a certain speed (1300m / s-2200m / s). The fragments gradually become stable during the flying process and will fly in the air with the surface with the least resistance, that is, the windward area of ​​the fragments. The outline and area of ​​the holes formed by the fragments penetrating the aluminum plate are positively correlated with the outline and area of ​​the windward surface of the fragments, which can characterize the actual fragment characteristics.

[0037] This embodiment provides a fragment mass distribution assessment method based on fragment perforation contour images, which uses computer vision detection technology and multi-level grayscale segmentation technology to automatically obtain the perforation contour dimensions of all fragments, and then obtain the fragment mass distribution results through conversion relationships. Specifically, the method includes the following steps:

[0038] S1. Obtaining images of the aluminum alloy sheet after the test;

[0039] S2. Process the image obtained in step S1;

[0040] S3. Based on the processed images, automatically obtain the outline dimensions of all fragment perforations;

[0041] S4. Obtain the fragment mass distribution result through the fragment perforation profile size.

[0042] Specifically, in step S2, ImageJ image processing software is used to perform binarization processing on the perforations, and the processing implementation process is as follows: Figure 5 As shown, the specific steps include:

[0043] S21. First, obtain the perforation image of the fragment through the thin sampling plate and select the image;

[0044] S22. Setting the fragment perforation area threshold;

[0045] S23. Separation of mutually adhered and overlapping pore particles;

[0046] S24. Set the particle size range and delete the stuck particles;

[0047] S25. expanding the particles, filling the cavities, etc.;

[0048] S26. Keep the processed image.

[0049] It should be noted that although the present invention is disclosed as above by specific embodiments, the above embodiments are not intended to limit the present invention. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A fragment mass distribution test device based on fragment perforation profile image, comprising a test sample, an aluminum alloy sheet, and a recovery box; characterized in that: Aluminum alloy thin plates are used to analyze the perforation shape of fragments; the aluminum alloy thin plates are placed on both sides of the metal shell, and the center of the metal shell and the center of the aluminum plate are on the same horizontal plane; a recovery box is used to recover the fragments formed after the test sample explodes; the recovery box is placed behind the aluminum alloy thin plates on both sides; the fragment recovery angle θ = 2*2×arctan -1 (0.75 / 1.5)=106.26°.

2. The fragment mass distribution test device based on fragment perforation profile image according to claim 1 is characterized in that: The test sample is a metal shell and is placed horizontally 1 meter above the ground.

3. The fragment mass distribution test device based on fragment perforation profile image according to claim 1, characterized in that: The aluminum alloy thin plate has a length of 2.5 m, a width of 1.5 m, and a thickness of 2 mm.

4. The fragment mass distribution test device based on fragment perforation profile image according to claim 1, characterized in that: The recycling box has equal length and width, and a depth of 0.5m.

5. The fragment mass distribution test device based on fragment perforation profile image according to claim 1, characterized in that: The recycling box is filled with fine sand, and the fragments are recovered using sandbox recycling technology.

6. A fragment mass distribution assessment method based on fragment perforation profile image, characterized in that: The method comprises the steps of: S1. Obtaining images of the aluminum alloy sheet after the test; S2. Process the image obtained in step S1; S3. Based on the processed images, automatically obtain the outline dimensions of all fragment perforations; S4. Obtain the fragment mass distribution result through the fragment perforation profile size.

7. The method for evaluating fragment mass distribution based on fragment perforation profile image according to claim 6, characterized in that: In step S2, ImageJ image processing software is used to perform binarization processing on the perforations.

8. The fragment mass distribution assessment method based on fragment perforation profile image according to claim 7, characterized in that: The use of ImageJ image processing software to perform binarization processing on the perforation specifically includes the following steps: S21. Select a picture; S22. Setting a threshold; S23. Separation of adherent particles; S24. Set the particle size range and delete the stuck particles; S25. expanding the particles, filling the cavities, etc.; S26. Keep the processed image.

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