Explosion forming projectile tail skirt regulation and control shaped charge liner

Abstract

The invention discloses an explosion-formed bullet tail skirt regulation and control shaped charge liner, which is characterized in that by controlling the grooving mode, depth and quantity distribution of the shaped charge liner, pressure relief points are formed when detonation waves act on the shaped charge liner, and the surface of the shaped charge liner is subjected to non-uniform detonation pressure to generate pressure gradient, so that the edge part of the shaped charge liner generates a speed difference in the overturning and crushing processes; and the tail skirt structure is formed after shearing or extrusion is generated by slippage among the grooves. According to the invention, the symmetry degree of the tail skirt of the EFP under detonation loading can be improved, the position of the mass center of the EFP is optimized, long-distance stable flight of the EFP with a large length-diameter ratio is realized, and a basis is provided for reaching the optimal damage performance of the EFP.

Description

Technical Field

[0001] The invention belongs to the technical field of projectiles, and in particular relates to an explosively formed projectile tail skirt controllable charge liner. Background Art

[0002] Explosively Formed Projectile (EFP) is formed by the acceleration and flipping of the metal liner under the detonation of the explosive charge, relying on its own kinetic energy and aerodynamic characteristics to fly long distances to attack the top of the target. Due to its advantages such as insensitivity to explosion height and significant after-target effect, it is widely used in terminal-sensitive projectiles, top-attack missiles, cruise missiles and unattended ammunition systems. It is the main destructive element of top-attack anti-armor smart ammunition and the focus of anti-armor target warhead research in various countries around the world.

[0003] Typical EFP warhead structure is as follows: Figure 4 As shown: It is mainly composed of a shell 1, a charge 2, a charge liner 3, a pressure screw 4, etc. After the detonator is detonated, the high-energy explosive loaded in the EFP warhead is detonated, and the blast wave causes the charge liner to flip and squeeze to form a high-speed, stable flying EFP damage element, with a forming speed range of about 1500 to 2500 m / s, which hits and penetrates the armored target within the required distance. Relying on the fragments formed by the EFP remnants entering the target and the target plate breaking, effective damage to the personnel and equipment inside the target is achieved.

[0004] With the improvement of advanced protective equipment technologies such as composite armor and reactive armor of the new generation of main battle tanks in various countries, it is difficult for existing quasi-balls or small aspect ratio EFPs to reliably damage the top main armor after penetrating composite armor or detonating reactive armor. According to the damage mechanism of EFP to the target, the research focuses on how to form a compact, elongated high-speed projectile with good flight stability so as to achieve the best damage performance when penetrating armored targets. The research aims to improve the damage capability by lengthening the projectile to form a large aspect ratio EFP and increase the specific kinetic energy to achieve higher armor-piercing power.

[0005] The forming process of EFP is that a spherical detonation wave is formed inside the charge after detonation, and a stress wave is formed on the liner. The liner is overturned and squeezed to form EFP under the pressure load of the detonation wave and stress wave. The formed EFP is difficult to form a completely symmetrical structure due to the influence of assembly and material properties. With the increase of EFP aspect ratio and flight speed, its asymmetry leads to a sharp decline in flight stability, the EFP's target attitude is deteriorated, and reliable armor penetration cannot be achieved, and even the target hit rate is affected.

[0006] At present, the formation method of EFP tail skirt is mainly studied at home and abroad by changing the warhead detonation mode, detonation point offset, special-shaped shell structure, setting wave modulator, metal patch on the surface of liner and other technical means. The development of related research has achieved certain results, but the traditional technical means have many constraints on EFP warhead charge, detonation device, shell, liner structure, etc., and the shapes are different. It is not universal and difficult to promote and apply to EFP warhead models with different calibers and design structure requirements. Therefore, in order to further improve the flight stability of EFP and adapt to the structural design requirements of various platforms, it is necessary to design a liner that can regulate the tail skirt of explosively formed projectiles. By taking different ways of pre-grooving treatment on the liner, the shaping control of EFP tail skirt can be realized, thereby improving the flight stability. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides an explosively formed projectile tail skirt control liner, which controls the distribution of the groove mode, depth and number of the liner, forms a pressure relief point when the detonation wave acts on the liner, and the surface of the liner is subjected to uneven detonation pressure to produce a pressure gradient, so that the edge of the liner produces a speed difference during the flipping and crushing process, so that the slip between each groove produces shear or extrusion to form a tail skirt structure. The present invention can improve the symmetry of the EFP tail skirt under detonation loading, optimize the center of mass position of the EFP, and realize the long-distance stable flight of the EFP with a large aspect ratio, providing a basis for achieving the best damage performance of the EFP.

[0008] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0009] An explosively formed projectile tail skirt control liner, by controlling the distribution of the groove pattern, depth and number of the liner, a pressure relief point is formed when the detonation wave acts on the liner, and the surface of the liner is subjected to uneven detonation pressure to produce a pressure gradient, so that the edge of the liner produces a speed difference during the overturning and crushing process, so that the slip between the grooves produces shear or extrusion to form a tail skirt structure;

[0010] When the liner groove is a sawtooth groove, i grooves are cut along the axial direction at the position where the edge of the liner is deep into Li, and the depth of each groove is Hi, the width is Di, and the angle is θi; L1≦L2≦L3..., H1≦H2≦H3..., D1≥D2≥D3..., where i=1,2,3,4....;

[0011] When the liner groove engraving method is circular array groove, a groove with an angle of θ is made at a position with a diameter of φ on the liner. According to the EFP tail skirt control requirements, the groove diameter φ is 0.7 to 0.7 times the liner diameter φy, the groove angle θ is 60 to 120°, and the number of arrays is 6 to 12.

[0012] Preferably, the liner structure is a disc-shaped, conical, arc-cone combination shape, spherical segment shape, or eccentric sub-hemispherical structure.

[0013] Preferably, the θi is 30-90°.

[0014] Preferably, the sawtooth groove is a type of T-groove, U-groove, or V-groove according to the EFP tail skirt regulation requirements, and the number i of the grooves is 3 to 5.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention proposes a charge liner for regulating the tail skirt of EFP. The charge liner structure is designed by two prefabricated groove methods, namely, sawtooth groove type and circular array groove type, to improve the symmetry of the tail skirt of EFP under detonation loading, optimize the center of mass position of EFP, realize the long-distance stable flight of EFP with large aspect ratio, and provide a basis for achieving the best damage performance of EFP. Compared with the existing technology, it breaks through the constraints of EFP warhead charge, detonator, shell, charge liner structure and other conditions, and can be generally used for charge liner structures such as cone, arc-cone combination, spherical segment, eccentric sub-hemispherical, etc., which is convenient for engineering promotion based on the existing charge liner structure and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a sawtooth grooved medicine liner of the present invention;

[0018] Figure 2 This is a schematic diagram of a circular array slotted liner of the present invention;

[0019] Figure 3 The EFP forming calculation diagrams of the ungrooved and grooved liner according to the embodiment of the present invention, a is the ungrooved liner, b is the serrated grooved liner, and c is the circular array grooved liner;

[0020] Figure 4 This is a schematic diagram of a typical EFP warhead structure.

[0021] Description of the drawings: 1-shell, 2-charge, 3-charge liner, 4-pressing screw. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] The purpose of the present invention is to propose an explosively formed projectile tail skirt control liner, and the liner structure is designed by two prefabricated grooving methods: a serrated grooving type and a circular array grooving type, so as to improve the symmetry and density of the EFP tail skirt under detonation loading, thereby improving the flight stability of the EFP, realizing the long-distance stable flight of the EFP with a large aspect ratio, and providing a basis for achieving the best damage performance of the EFP.

[0024] The technical solution to achieve the purpose of the present invention is: an explosively formed projectile tail skirt regulating liner, which forms a pressure relief point when the detonation wave acts on the liner by controlling the distribution of the groove pattern, depth and number of the liner grooves. The surface of the liner is subjected to uneven detonation pressure to produce a pressure gradient, so that the edge of the liner produces a speed difference during the flipping and crushing process, so that the slip between the grooves produces shear or extrusion to form an ideal tail skirt structure; the liner structure is approximately disc-shaped, and is also suitable for liner structures such as conical, arc-cone combination, spherical, and eccentric sub-hemispherical.

[0025] Specific implementation methods of different prefabricated grooved liner structures are as follows Figure 1 , Figure 2 shown.

[0026] Figure 1 It is a sawtooth grooved liner, where i grooves are carved along the axial direction at the position of Li deep into the edge of the liner, and each groove has a depth of Hi, a width of Di, and an angle of θi. Generally, L1≦L2≦L3..., H1≦H2≦H3..., D1≥D2≥D3..., where i=1, 2, 3, 4...; θ is 30-90°.

[0027] According to the EFP tail skirt control requirements, the type of groove can be T-shaped groove, U-shaped groove, V-shaped groove, etc., and the number of grooves i is generally 3 to 5.

[0028] The liner is subjected to the pressure load of the detonation wave and the stress wave. The spherical detonation wave first propagates to the liner area I to form the EFP main rod, and the edge of the liner in area II forms the tail skirt. By making serrated grooves on the edge of the liner, the wall thickness of the liner at the edge can be reduced. Since the wall thickness of the liner at the groove is thinner, the detonation wave acts on the cavity in the groove to form a pressure relief point. After being subjected to the pressure load, it has a speed difference with the thicker liner around it, and then shears and breaks, forming a regular EFP tail skirt. In addition, the groove depth difference of the edge serrated groove can make the EFP edge fracture smoother, avoiding the problem that the incomplete fracture of a single groove affects the forming of the EFP main rod.

[0029] By pre-grooving and fracturing, the mass proportion and diameter of the EFP tail skirt are reduced, so that the center of mass of the EFP moves forward to increase static stability, reduce flight resistance, and greatly improve the flight stability of the EFP.

[0030] Figure 2 It is a circular array slotted charge liner, with slots of angle θ at positions with diameter φ on the charge liner. According to the EFP tail skirt control requirements, the slot diameter φ is generally 0.7 to 0.7 times the liner diameter φy, the slot angle θ is 60 to 120°, and the number of arrays is generally 6 to 12.

[0031] By slotting the edge array of the liner, when the spherical detonation wave propagates from the unslotted part 2 to the slotted part 1, since the mass distribution of the unslotted part 2 at the edge of the liner is larger than that of the slotted part 1 at the edge, the unslotted part 2 at the edge of the liner is crushed at a lower speed than the slotted part 1 at the edge. When the detonation wave propagates to the slotted cavity, a pressure relief point will be formed. The pressure on the liner microelement at the pressure relief point will be higher than that on the nearby microelement. The farther away from the pressure relief point, the greater the pressure on the liner. This change in pressure gradient causes the unslotted part 2 of the liner tail skirt to be squeezed toward the position of the slotted part 1 under the pressure load during formation, thereby forming regular wrinkles and then forming a symmetrical tail skirt.

[0032] By pre-grooving and setting the extrusion direction of the tail skirt, the symmetry of the EFP tail skirt formation is improved, the shock wave boundary layer interference generated by the EFP during flight is reduced, and the long-distance flight stability of the EFP is ensured, thereby achieving long-distance precision strike tactical indicators.

[0033] The ANSYS / LS-DYNA program was used to perform numerical simulation calculations on the EFP molding of different prefabricated grooved liner structures. The calculations adopted the fluid-solid coupling algorithm of Euler unit and Lagrangian unit, the liner was set to automatic contact, the air outer layer was set to a non-reflective boundary, and the full model was established for simulation.

[0034] EFP molding process Figure 3 As shown, a is an ungrooved liner, b is a serrated grooved liner, and c is a circular array grooved liner.

[0035] When the charge detonates, the spherical detonation wave first propagates to the center of the liner to form the EFP main rod, which is accelerated in front, and the tail skirt formed by the edge of the liner is accelerated in the back. Under the action of the detonation wave, the sawtooth grooved liner produces an obvious fracture circle. Compared with the EFP formed by the ungrooved liner, the diameter of the EFP tail skirt formed by the sawtooth grooved liner is smaller; the circular array slotted liner is squeezed toward the slot to form regular wrinkles. Compared with the EFP formed by the ungrooved liner, the tail skirt formed by the circular array slotted liner has better symmetry.

[0036] The key points of the present invention are as follows:

[0037] 1. Sawtooth grooved liner, grooves are cut along the axial direction at the position where the edge of the liner is deep into Li, the depth of the groove is Hi, the width is Di, and the angle is θi. Generally, L1≦L2≦L3..., H1≦H2≦H3..., D1≥D2≥D3..., where i=1, 2, 3, 4...; θ is 30~90°. According to the EFP tail skirt control requirements, the type of groove can be T-groove, U-groove, V-groove, etc., and the number of grooves i is generally 3~5.

[0038] 2. Array slotted liner: slots with an angle of θ are made at the position of the liner diameter φ. According to the EFP tail skirt control requirements, the slot diameter φ is generally 0.7 to 0.7 times the liner diameter, the slot angle θ is 60 to 120°, and the number of arrays is generally 6 to 12.

[0039] 3. The charge liner structure is approximately disc-shaped, and can be used in cone-shaped, arc-cone combined, spherical, eccentric sub-hemispherical and other structures.

Claims

1. An explosively formed projectile tail skirt control liner, characterized in that: By controlling the distribution of the groove pattern, depth and number of the liner grooves, a pressure relief point is formed when the detonation wave acts on the liner. The surface of the liner is subjected to uneven detonation pressure to generate a pressure gradient, which causes a speed difference at the edge of the liner during the overturning and crushing process, so that the slip between the grooves generates shear or extrusion to form a tail skirt structure. When the liner groove is a sawtooth groove, i grooves are cut along the axial direction at the position where the edge of the liner is deep into Li, and the depth of each groove is Hi, the width is Di, and the angle is θi; L1≦L2≦L3..., H1≦H2≦H3..., D1≥D2≥D3..., where i=1,2,3,4....; When the liner groove engraving method is circular array groove, a groove with an angle of θ is made at a position with a diameter of φ on the liner. According to the EFP tail skirt control requirements, the groove diameter φ is 0.7 to 0.7 times the liner diameter φy, the groove angle θ is 60 to 120°, and the number of arrays is 6 to 12.

2. The explosively formed projectile tail skirt control liner according to claim 1, characterized in that: The liner structure is a dish-shaped, cone-shaped, arc-cone combined shape, spherical segment shape, or eccentric sub-hemispherical structure.

3. The explosively formed projectile tail skirt control liner according to claim 1, characterized in that: The θi is 30 to 90°.

4. The explosively formed projectile tail skirt control liner according to claim 1, characterized in that: The sawtooth groove is selected according to the EFP tail skirt regulation requirements. The type of the groove is one of a T-shaped groove, a U-shaped groove and a V-shaped groove. The number i of the grooves is 3 to 5.

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