A high energy-absorbing recoverable buffer structure suitable for penetration ammunition primer buffer

Abstract

This invention discloses a high-energy-absorbing and recoverable buffer structure suitable for penetrating munition deflection, which is a cell array structure. The upper support plate of the single-cell structure has a first symmetrical curved cross-shaped hyperbolic beam structure at its lower end. The first symmetrical curved cross-shaped hyperbolic beam structure is connected to the upper support plate by four first support columns. The upper end of the lower support plate has a second symmetrical curved cross-shaped hyperbolic beam structure. The second symmetrical curved cross-shaped hyperbolic beam structure is connected to the lower support plate by four second support columns. The first and second symmetrical curved cross-shaped hyperbolic beam structures are connected by four third support columns, with each pair of third support columns dividing a single curved beam into four equal parts. The four first support columns and four second support columns are positioned correspondingly. This invention achieves high energy absorption while maintaining a certain degree of recoverability.

Description

Technical Field

[0001] This invention belongs to the field of penetrating ammunition detonation buffers, and in particular, it is a high-energy-absorbing and recoverable buffer structure suitable for penetrating ammunition detonation buffers. Background Technology

[0002] With the development of information technology and intelligent systems, the modern battlefield environment is increasingly complex and dynamic. Upgraded defensive methods have made the penetration environments experienced by penetrating munitions more complex. The development of intelligent munitions requires penetration fuses to possess multi-target adaptive recognition and engagement capabilities, able to distinguish different target information and achieve precise detonation based on the set information. When striking high-strength, thick targets, the fuse experiences prolonged high overload; when striking multi-layered targets, the fuse experiences multiple strong impacts at short intervals. Therefore, for penetration fuses, impact resistance is a bottleneck restricting their development, and missile-fuselage buffering is an important method to reduce the overload experienced by the fuse.

[0003] In modern warfare, with the increase in the thickness of underground fortifications from 6m to 10m and the improvement in protective strength from C40 to C100, the penetration velocity of warheads has exceeded 1500m / s. Existing fuze buffering protection technologies still suffer from insufficient overload resistance in the face of high impact overload caused by multi-material, multi-layered, high-hardness, and hypersonic penetration. Currently, commonly used materials for projectile-fuze buffering include non-metallic elastic materials such as rubber and polytetrafluoroethylene (PTFE), and foamed metals. While elastic materials have certain advantages in deformation recovery, they cannot maintain high energy absorption under prolonged high overload. Therefore, they cannot effectively protect the fuze against ultra-high-speed penetration of single-layer thick targets, easily leading to fuze failure. When foam metal penetrates multiple target plates, the projectile is compacted and cannot rebound during the penetration of the first target plate. When penetrating the second target plate, a gap is generated between the fuze and the outer shell. The rigid contact between the compacted foam metal and the fuze will generate a very high acceleration peak, thereby damaging the fuze structure, causing incomplete detonation of the projectile, and failing to achieve maximum damage effectiveness.

[0004] Therefore, there is an urgent need to design a new type of energy-absorbing material structure that combines the advantages of the two types of cushioning materials mentioned above, requiring it to have high energy absorption while maintaining a certain degree of recoverability. Summary of the Invention

[0005] The purpose of this invention is to provide a high-energy-absorbing and recoverable buffer structure suitable for penetrating ammunition deflection buffers, which has high energy absorption while maintaining a certain degree of recoverability.

[0006] The technical solution to achieve the purpose of this invention is as follows:

[0007] A high-energy-absorbing and recoverable buffer structure suitable for penetrating munition deflection is a cell array structure comprising multiple unit cell structures; the unit cell structure includes an upper support plate, a lower support plate, a first symmetrical curved cross-shaped hyperbolic beam structure, a first support column, a second symmetrical curved cross-shaped hyperbolic beam structure, a second support column, and a third support column;

[0008] The lower end of the upper support plate is provided with a first symmetrical curved cross-shaped hyperbolic beam structure, which bends towards the upper support plate. The first symmetrical curved cross-shaped hyperbolic beam structure is connected to the upper support plate by four first support columns, which are respectively connected to the four corners of the end support plate. The upper end of the lower support plate is provided with a second symmetrical curved cross-shaped hyperbolic beam structure, which bends towards the lower support plate. The second symmetrical curved cross-shaped hyperbolic beam structure is connected to the lower support plate by four second support columns, which are respectively connected to the four corners of the lower support plate. The first symmetrical curved cross-shaped hyperbolic beam structure and the second symmetrical curved cross-shaped hyperbolic beam structure are connected by four third support columns, with each pair of third support columns dividing a single curved beam into four equal parts. The four first support columns and the four second support columns are positioned correspondingly to form a stable structure during compression.

[0009] The significant advantages of this invention compared to existing technologies are:

[0010] Balancing high energy absorption and recoverability of the buffer material under multiple continuous strong impacts, a bistable design is achieved based on a symmetrical hyperbolic beam microstructure. During impact compression, energy absorption is achieved through the bending deformation of the beam. Based on the stable bistable structure, switching between two steady states is possible. This design can meet the buffer protection requirements of fuzes when penetrating munitions penetrate various complex targets, improving the control of the fuze's detonation point. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the cell structure and cell array of the buffer material.

[0012] Figure 2 This is a diagram illustrating the compression and recovery process of the cell structure of a buffer material.

[0013] Figure 3 This is a schematic diagram of the preparation of buffer materials.

[0014] Figure 4 This is a schematic diagram of the installation of buffer material in a penetrating projectile.

[0015] Figure 5 This is a schematic diagram of a penetrating warhead penetrating multiple layers of targets.

[0016] Figure 6 This is a diagram showing the results of a static compression experiment on the buffer material.

[0017] Figure 7 This is a diagram showing the results of multiple impact acceleration tests on the fuse before and after buffering with buffer material. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Combination Figure 1 This is a schematic diagram of the unit cell structure and cell array of the buffer material. The required size can be obtained by arranging and combining the cells according to the elastic space. The array of unit cells is connected together by upper and lower support plates, and the bending beams of each cell are in contact with each other but do not affect each other. The lower support plate 2 of the upper unit cell structure serves as the upper support plate 1 of the lower buffer material unit cell structure. The lower end of the upper support plate 1 of the unit cell structure is provided with a first symmetrical curved cross-shaped hyperbolic beam structure 3, which bends toward the upper support plate 1. The first symmetrical curved cross-shaped hyperbolic beam structure 3 is connected to the upper support plate 1 by four first support columns 4, which are respectively connected to the four corners of the lower support plate 1. The upper end of the lower support plate 2 is provided with a second symmetrical curved cross-shaped hyperbolic beam structure 5, which bends toward the lower support plate 2. The second symmetrical curved cross-shaped hyperbolic beam structure 5 is connected to the lower support plate 2 by four second support columns 6, which are respectively connected to the four corners of the lower support plate 2. The first symmetrical curved cross-shaped hyperbolic beam structure 3 and the second symmetrical curved cross-shaped hyperbolic beam structure 5 are connected by four third support columns 7, and every two third support columns 7 divide a single curved beam into four equal parts. The four first support columns 4 and the four second support columns 6 are positioned correspondingly to form a second stable structure through contact during compression (the first support column 4 contacts the corresponding second support column 6).

[0020] The symmetrically curved, cross-shaped hyperbolic beam structure, with its symmetrical upper and lower sections supported by four columns, ensures sufficient support for the curved beam under compressive bending. Its main structural parameters include the bending center height *h*, the beam thickness *t*, the support height *s*, and the outer contour dimension *l* of the structural cells. The support height *s* determines the compression limit height; after full compression, the compression limit height is 2s. The outer contour dimension *l* can be minimized to allow for more cell combinations within a unit volume, improving the overall overload resistance of the composite structure. Under uniaxial compression, the force *F* on this structure can be expressed as…

[0021]

[0022] Compression energy absorption can be expressed as

[0023] Where Q = h / t, Δ = Δh / t, Δh is the compression stroke, and Δh maxThe maximum compression is given by the formula above. It can be seen that the maximum load-bearing capacity of the structure is proportional to the dimensionless parameter Q, while parameter Δ is a motion parameter and is independent of the structure. Δh is the compression stroke, and d(Δh) represents the integration over Δh. Since the compression process is nonlinear, the energy absorption during the entire process can be expressed as the integral of force and displacement over the compression stroke. Furthermore, the energy absorption value ΔE during compression is positively correlated with both stress and compression stroke. Therefore, the value of parameter Q should be increased as much as possible within the limits allowed by the printing process. In this paper, Q is set to 5.67, which is the maximum value achieved within the allowable range of the printing process.

[0024] During the impact compression process, the curved beam compresses, and after reaching its compression limit, the structure switches to the first steady state, maintaining a certain supporting capacity. After the impact, the curved beam can freely recover (the recovery rate can reach 90%), effectively coping with continuous impact energy absorption. Its compression deformation and recovery process is as follows: Figure 2 As shown. This structure is a bistable structure, and its energy absorption is mainly achieved through the compression of the curved beam structure. To ensure recoverability and prevent the structure from collapsing under the compression limit, the following is used: Figure 1 The height of the four support columns at the top and bottom is designed to achieve this. That is, when the upper and lower support columns are in contact at the compression limit, the curved beam structure only undergoes elastic deformation. Under subsequent compression, the support columns mainly bear the load. Therefore, when the load disappears, the curved beam can recover freely and can withstand multiple cyclic impact compressions.

[0025] Figure 3 This is a schematic diagram of the buffer material preparation process. First, the 3D model is discretized into 2D cross-sectional shapes using software, and a scanning path is planned. Before the laser scan selects the area, a powder-spreading roller spreads metal powder onto the laser processing area. Based on the laser scanning information, the scanning galvanometer is deflected to selectively irradiate the processing area with the laser beam, resulting in the current 2D cross-section. The 2D solid and forming areas are then thinned, and the above process is repeated to accumulate the product layer by layer. During powder spreading and laser irradiation forming, an inert gas should be used to prevent oxidation during the forming process. Ar / N2 is used as the protective gas.

[0026] The high-energy-absorbing, recoverable cushioning material proposed in this invention is a symmetrical curved beam bistable cushioning material achieved through structural parameter optimization and 3D printing technology, based on a bistable structure. TC4 titanium alloy possesses a series of advantages such as excellent corrosion resistance, low density, high specific strength, and good toughness and weldability, and is widely used in aerospace materials. Due to its low density and ultra-hardness, it has also been frequently used in protective energy-absorbing materials in recent years. The structure designed in this paper uses TC4 titanium alloy material and is integrally fabricated by 3D printing, with a total thickness of 3.0 mm and printing parameters set to a layer thickness of 0.1 mm.

[0027] This study employs SLM (Selective Laser Melting) printing technology, utilizing multi-beam laser selective melting additive manufacturing combined with an online monitoring system and an ultrafast laser system to achieve efficient, integrated part forming. The scanning speed is 5 m / s, the substrate temperature is set to 170℃, and the protective gas is Ar / N2 to prevent metal oxidation during printing, which could cause a sudden change in performance. Because the structure designed in this work is a cross-shaped symmetrical curved beam with a large bending angle relative to the horizontal direction of the laser scanning path, it is highly susceptible to beam collapse, leading to forming difficulties. To address this issue, a substrate tilting method is used to minimize the angle between the curved beam and the horizontal direction of the laser selection area, ensuring stable forming.

[0028] In this invention, a real-time example is demonstrated by penetrating a multi-layered target plate. The fuze and the projectile body are secured together by a clamping screw at the tail, wherein a cushioning material is installed between the projectile body and the fuze. Figure 4 This is a schematic diagram of the internal structure of the buffer material in the missile. Figure 5 A schematic diagram illustrating the penetration of a warhead into multiple target layers.

[0029] Figure 6 The figure shows the results of a static compression test on the buffer material. It can be seen that the buffer material has a large plateau stress and can absorb a large amount of energy.

[0030] Figure 7 This is a graph showing the results of multiple impact acceleration tests on the fuze before and after buffering with a buffer material. After buffering with the buffer material, the peak acceleration can be reduced by more than 45%, and even after 5 consecutive impacts, the peak acceleration can still be reduced by more than 27%.

[0031] It achieves a low-density, lightweight design with a relative density as low as 1.12 g / cm³. 3 It is similar to foamed metal materials. Moreover, through microstructure design, the unit cell structure size is only 3.0mm×3.0mm×3.0mm, which can be arrayed according to the size space of the spring-loaded connection to achieve adaptability and universality.

[0032] The buffer material prepared in this invention underwent static compression and dynamic impact tests. Static compression tests revealed that the material exhibits a large plateau stress, meeting the basic mechanical requirements of high-energy-absorbing materials. Dynamic impact tests demonstrated that the material significantly reduces the peak acceleration experienced by the fuze under multiple consecutive impacts, achieving continuous energy absorption under multiple impacts. Verification using a Marshall hammer impact test system and a multiple impact test system confirmed that it can absorb over 40% of the peak energy under impacts exceeding 20,000g, and maintain stable recoverable performance after five consecutive impacts.

[0033] This material achieves a bistable design based on a symmetrical hyperbolic beam microstructure. During impact compression, it absorbs energy through the bending deformation of the beam. Based on its stable bistable structure, it can switch back and forth between two steady states. Compared to commonly used polymer cushioning materials such as rubber, this material exhibits greater plateau stress, enabling greater energy absorption. Compared to foamed metal cushioning materials, it achieves good recoverability due to its stable structure, providing sufficient cushioning for multiple impacts at short intervals, and can provide fuze cushioning protection against multi-layered target penetration.

Claims

1. A high-energy-absorbing, recoverable buffer structure suitable for penetrating munition detonation buffers, comprising a cell array structure including multiple single-cell structures; characterized in that, The unit cell structure includes an upper support plate, a lower support plate, a first symmetrical curved cross-shaped hyperbolic beam structure, a first support column, a second symmetrical curved cross-shaped hyperbolic beam structure, a second support column, and a third support column; the array of unit cells is connected together by the upper and lower support plates, and the curved beams of each unit cell are in contact with each other but do not affect each other; The lower end of the upper support plate is provided with a first symmetrical curved cross-shaped hyperbolic beam structure, which bends towards the upper support plate. The first symmetrical curved cross-shaped hyperbolic beam structure is connected to the upper support plate by four first support columns, which are respectively connected to the four corners of the end support plate. The upper end of the lower support plate is provided with a second symmetrical curved cross-shaped hyperbolic beam structure, which bends towards the lower support plate. The second symmetrical curved cross-shaped hyperbolic beam structure is connected to the lower support plate by four second support columns, which are respectively connected to the four corners of the lower support plate. The first symmetrical curved cross-shaped hyperbolic beam structure and the second symmetrical curved cross-shaped hyperbolic beam structure are connected by four third support columns. Each pair of third support columns divides a single curved beam into four equal parts. The four first support columns and the four second support columns are positioned correspondingly, so that the first support columns and the corresponding second support columns contact each other to form a second steady-state structure during compression. While the upper and lower support columns are under ultimate compression, the curved beam structure only undergoes elastic deformation. Under subsequent compression, the support columns bear the force, forming a second steady-state structure with recovery capability. After the ultimate compression load is unloaded, the structure switches to the first steady state and maintains a certain support capacity.

2. The high-energy-absorbing, recoverable buffer structure suitable for penetrating ammunition detonation buffers according to claim 1, characterized in that, It is a multi-layer cell array structure, with the lower support plate of the upper unit cell structure serving as the upper support plate of the lower buffer material unit cell structure.

3. The high-energy-absorbing, recoverable buffer structure suitable for penetrating ammunition detonation buffers according to claim 1, characterized in that, It uses TC4 titanium alloy material.

4. The high-energy-absorbing, recoverable buffer structure suitable for penetrating ammunition detonation buffers according to claim 1, characterized in that, It is installed between the projectile body and the fuse.

5. The high-energy-absorbing, recoverable buffer structure suitable for penetrating ammunition detonation buffers according to claim 1, characterized in that, It is made using 3D printing technology and employs a base tilting method to reduce the angle between the curved beam and the horizontal direction of the laser selection area.

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