High-effect warhead material and charge combination design method

Abstract

The invention discloses a high-effect warhead material and a charge combination design method, and relates to the technical field of warheads, the high-effect warhead material comprises an outer layer structure of a steel-copper composite shaped charge liner and composite explosives filled in the outer layer structure, and the composite explosives comprise CL-20-based nano thermite and 8701 explosives. And according to the geometrical shape and combat requirements of the warhead, the distribution rule of nanometer gradient charging is designed. The charge density or composition gradually changes in the specific direction (such as the radial direction or the axial direction), and the charge density is transited from 1.75 g / cm < 3 > (outer layer) to 2.15 g / cm < 3 > (inner layer). The crystal face orientation degree of CL-20 crystal (010) is regulated to be larger than 85% through the EBSD technology, and a detonation wave propagation dominant channel in the [001] direction is constructed. Through the polycrystalline orientation gradient charging structure, the detonation wave impedance is continuously changed through the gradient design, the interface reflection energy loss is reduced, and the actual measurement specific impulse is increased by 42%. The jet flow kinetic energy reaches 1.7 times of that of a traditional design by utilizing high-density enhanced kinetic energy of steel and plasticity optimized forming of copper.

Description

Technical Field

[0001] The present invention relates to the technical field of warheads, and particularly relates to a design method for a high-performance warhead material and charge combination. Background Art

[0002] The warhead is a key component in a weapon system for damaging targets, and its performance directly affects the combat effectiveness of the weapon. Traditional warhead charges usually adopt a uniform distribution method. However, in practical applications, this charging method has problems such as low energy release efficiency, lack of microscopic control, and limited damage effect.

[0003] In recent years, the application of nanotechnology in the energetic field has provided new ideas for solving the above problems. By gradient structure design, the charge density or composition gradually changes along a specific direction to achieve micro-macro cross-scale correlated fracture, but there is little research at present.

[0004] Therefore, it is particularly important to improve the damage efficiency of the warhead and the adaptability of the warhead to environmental changes through the synergy of nano-gradient design and crystal plasticity regulation. Summary of the Invention

[0005] The purpose of the present invention is to provide a design method for a high-performance warhead material and charge combination, aiming to improve the energy utilization rate and damage efficiency of the warhead through the combination of a nano-gradient charge structure and crystal plasticity theory.

[0006] The present invention discloses a high-performance warhead material, including an outer structure of a steel-copper composite liner and a composite explosive filled inside the outer structure. The composite explosive includes a CL-20-based nano-thermite and 8701 explosive, and the CL-20-based nano-thermite is Al@Ni core-shell particles.

[0007] Preferably, the steel-copper composite liner has a steel outer cover and a copper inner cover, the thickness of the outer cover is 5.5 mm, and the thickness of the inner cover is 3.2 mm.

[0008] Preferably, tungsten fibers with a BCC structure are implanted between the layers of the CL-20-based nano-thermite. The diameter of the tungsten fibers is 200 nm, and the aspect ratio is 15:1.

[0009] The present invention also provides a design method for a charge combination of a high-performance warhead material, including constructing a nano-gradient charge structure and regulating the crystal structure.

[0010] Preferably, the construction of the nano-gradient charge structure is such that the density or composition of the explosive changes in a gradient manner along a specific direction from CL-20 to 8701 explosive during charging. The density of the explosive increases from the outer layer to the inner layer during charging. The density of the explosive in the outer layer is 1.75 g / cm 3, the density of the inner explosive is 2.15 g / cm 3 . For example, the charge density gradually increases from the center of the warhead outwards and from the front end to the rear end of the warhead.

[0011] Preferably, the orientation of the tungsten fibers is <111>.

[0012] Preferably, the crystal structure regulation includes the following steps:

[0013] (1) Perform a surface scan on the CL-20-based nanothermite crystal by SEM to obtain an orientation imaging map;

[0014] (2) Use the texture analysis module to screen the proportion of the <010> crystal plane, and optimize the magnetic field parameters to make the orientation degree > 85%;

[0015] (3) Verify the preferred distribution in the <001> direction through the inverse pole figure, and establish the coupling relationship between the crystal plane orientation and the detonation wave propagation;

[0016] (4) Through the equal-channel angular pressing process, introduce a dislocation density gradient in the CL-20-based nanothermite crystal to inhibit the crack propagation in the non-<001> direction.

[0017] Preferably, the coupling relationship in step (3) is calculated by the crystal plasticity-detonation dynamics cross-scale equation, and the crystal plasticity-detonation dynamics cross-scale equation is:

[0018]

[0019] This model correlates the dislocation motion (microscopic) with the detonation wave propagation (macroscopic). Among them, x j is the spatial coordinate component, is the stress tensor component, ρ is the material density, the material derivative of the acceleration, is the shear strain rate of the α-th slip system, is the unit vector of the slip direction of the α-th slip system, is the unit vector of the normal of the slip plane of the α-th slip system.

[0020] Preferably, the dislocation density gradient in step (4) is 1×10 14 m -2 to 5×10 14 m -2 .

[0021] Therefore, the present invention adopts the above-mentioned high-performance warhead material and charge combination design method, and has the following beneficial effects:

[0022] The present invention innovatively proposes a polycrystalline orientation gradient charge structure. The gradient design enables the continuous change of the detonation wave impedance, reduces the energy loss due to interface reflection, and the measured specific impulse is increased by 42%. Using the high density of steel (7.83 g / cm 3 3) to enhance the kinetic energy and the plasticity of copper (dynamic yield strength of 0.09 GPa) to optimize the forming, the jet kinetic energy reaches 1.7 times that of the traditional design.

[0023] The application of crystal plasticity theory helps to improve the performance stability of the warhead material under different environmental conditions. By regulating the crystal structure, the thermal stress concentration caused by temperature change is reduced, and the crack resistance and environmental adaptability of the material are improved.

[0024] And an innovative crystal plasticity-detonation dynamics cross-scale equation is proposed:

[0025]

[0026] The calculation error is <3% (compared with molecular dynamics simulation). Description of the Drawings

[0027] Figure 1 It is the stress-strain nephogram of the gradient energetic material;

[0028] Figure 2 It is the accumulated shear strain nephogram of the gradient energetic material;

[0029] Figure 3 It is the performance diagram under the uniaxial tensile axial tension simulation of the charge structure, where (a) is the stress-strain curve of the multi-layer gradient energetic material; (b) is the curve of the accumulated plastic strain;

[0030] Figure 4 It is the display of the fixed crystal orientation pole figure of the energetic material through the EBSD technique;

[0031] Figure 5 It is the physical display diagram of the Al@Ni core-shell particles, where (a) is the macroscopic view of the Al@Ni core-shell particles and (b) is the microscopic view of the Al@Ni core-shell particles;

[0032] Figure 6 It is the curve diagram of the overpressure distribution on the surface of the liner. Detailed Embodiments

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will combine the drawings in the embodiments of the present invention Figures 1 to 6 to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "periphery", "lateral", "longitudinal", "length", "thickness", "angle", "upper", "lower", "left", "right", etc. indicating the orientation or position are only for simplifying the description of the present invention, rather than a specific position or orientation, and the above terms do not limit the present invention.

[0035] The present invention discloses a high-performance warhead material, including an outer structure of a steel-copper composite liner and a composite charge of CL-20-based nano-thermite and 8701 explosive inside the outer structure. The CL-20-based nano-thermite is Al@Ni core-shell particles, and the Al@Ni core-shell particles are as Figure 5 shown.

[0036] The steel-copper composite liner uses steel as the outer cover and copper as the inner cover. The thickness of the outer cover is 5.5 mm, and the thickness of the inner cover is 3.2 mm.

[0037] Tungsten fibers with a <111> preferred orientation of the BCC structure are implanted between the layers of the CL-20-based nano-thermite. The diameter of the tungsten fibers is 200 nm, and the aspect ratio is 15:1.

[0038] The present invention also provides a charge combination design method for a high-performance warhead material, including the construction of a nano-gradient charge structure and the regulation of the crystal structure.

[0039] The construction of the nano-gradient charge structure means that the density or composition of the explosive changes in a gradient along a specific direction (such as the radial or axial direction) from CL-20 to 8701 explosive during charging. When charging, the density of the explosive gradually increases from the outer layer to the inner layer. The density of the explosive in the outer layer is 1.75 g / cm 3 , and the density of the explosive in the inner layer is 2.15 g / cm 3 . For example, the charging density gradually increases from the center of the warhead to the outside, and increases from the front end to the rear end of the warhead.

[0040] Regulate the crystal structure, and regulate the orientation degree of the (010) crystal plane of the CL-20 crystal to be > 85% through the EBSD technology, and construct a preferential channel for the detonation wave to propagate in the

[001] direction.

[0041] Figure 1 and Figure 2 give the basic two-dimensional structure diagram of the gradient hierarchical charge. Combining Figure 3 (a) and (b) show that the large grains bear greater strain and the small grains bear greater stress. The calculation model uses a coupled finite element model of crystal plasticity and phase field method (CP-PFM-FEM), where the total energy formula:

[0042]

[0043] and the temperature integral forward difference method:

[0044]

[0045] θ k+1 = θ k + Δt k+1 p k

[0046] where L is the Helmholtz free energy per unit mass, u is the displacement, θ is the temperature, Γ is the crack, Ρ is the density, b represents the body force per unit mass, c represents the specific heat capacity, γ is the heat source per unit volume, and gc is the energy release rate. It can be seen that hot spots first occur in places with larger strains, that is, at the grain boundaries, and their overall propagation law is from large grains to small grains.

[0047] The EBSD technology regulates the <010> crystal plane orientation degree of CL-20 crystals to be > 85%, and constructs a preferential propagation channel for detonation waves in the <001> direction. CL-20 (hexanitrohexaazaisowurtzitane) has a cage-like three-dimensional molecular structure, and its different crystal planes show significant anisotropy during the detonation process. The lattice vibration mode in the <001> direction highly matches the detonation wave propagation direction, and the phonon propagation speed along this direction can reach 5.8 km / s, which is significantly higher than that in other directions (such as 4.2 km / s in the <100> direction). And because the <010> crystal plane of CL-20 is densely packed with nitro groups, a continuous oxidizer chain structure is formed along the <001> direction, which is conducive to the efficient transmission of the detonation reaction chain.

[0048] Through the electron backscatter diffraction (EBSD) technology, the Kikuchi pattern of CL-20 crystals can be monitored in real time, and its crystal plane orientation distribution can be analyzed ( Figure 4 ). The spatial resolution of EBSD reaches the sub-micron level (0.1 μm). Combining with the magnetic field-assisted self-assembly process, the <010> crystal plane orientation can be directionally regulated. Its operation process is as follows:

[0049] (1) Perform a surface scan of CL-20 crystals through SEM to obtain an orientation imaging map (OIM);

[0050] (2) Use the texture analysis module to screen the proportion of the <010> crystal plane, and optimize the magnetic field parameters to make the orientation degree > 85%;

[0051] (3) Verify the preferred distribution in the <001> direction through the inverse pole figure.

[0052] Establish the coupling relationship between the crystal plane orientation and the detonation wave propagation. The calculation results are calculated through the crystal plasticity-detonation dynamics multi-scale equation, and are:

[0053]

[0054] This model correlates dislocation motion (microscopic) with detonation wave propagation (macroscopic). Among them, x j is the spatial coordinate component, is the stress tensor component, ρ is the material density, the material derivative of acceleration, is the shear strain rate of the α-th slip system, is the unit vector of the slip direction of the α-th slip system, is the unit vector normal to the slip plane of the α-th slip system.

[0055] Energy transfer optimization: When the <010> crystal plane is highly oriented, the lattice vibration mode along the <001> direction forms a resonant coupling with the detonation wave pressure field, increasing the energy transfer efficiency to 92% (65 - 70% for traditional randomly oriented materials)

[0056] Wavefront flatness control: The detonation velocity of CL-20 in the <001> direction is less sensitive to curvature (when κ < 0.005 mm-1, the normal detonation velocity decreases at a rate of only 0.8% / mm-1), significantly better than RDX-based explosives (the decrease rate is 1.5% / mm -1 ).

[0057] By means of the ECAP (equal-channel angular pressing) process, a dislocation density gradient (1×10 14 m -2 to 5×10 14 m -2 ) is introduced into the CL-20 crystal to inhibit crack propagation in non-<001> directions.

[0058] Example 1 Anti-ship warhead

[0059] Adopt a double-curvature liner design (curvature radii R1 = 120 mm, R2 = 80 mm), and the gradient charge density transitions from 1.75 g / cm 3 to 2.15 g / cm 3 . The overpressure distribution curve of the liner of this design is as shown in Figure 6 . Its parameters and optimization effects are as shown in Table 1 below:

[0060] Table 1 Parameters and optimization effects of the anti-ship warhead

[0061]

[0062]

[0063] Perform performance verification on the anti-ship warhead provided in this example, and the results are as follows:

[0064] Detonation performance verification:

[0065] Wave velocity test: The actual measurement by a high-speed scanning camera shows that the detonation velocity of the CL-20-based charge after orientation regulation reaches 9,300 m / s along the <001> direction, which is about 12% higher than that of the randomly oriented material.

[0066] Damage effectiveness: In the application of anti-ship warheads, this design reduces the dispersion of the initial velocity distribution of fragments from ±20% to ±5%, and increases the success rate of continuously penetrating three layers of steel compartments (each layer is 20 mm thick) to 98%.

[0067] Compartment penetration ability:

[0068] Through numerical simulation and experimental verification, in the case of an 80-mm charge diameter, the EFP can continuously penetrate three layers of homogeneous steel compartments (each layer is 20 mm thick). During the penetration process, the peak pressure generated by the gradient charge reaches 35 GPa, and the aspect ratio of the fragments (L / D = 3.5) effectively inhibits tensile fracture, achieving a penetration depth of 240 mm (about 3 times the charge diameter).

[0069] Target plate test data:

[0070] Compared with the traditional single-layer charge, the penetration depth of the double-curvature gradient charge is increased to 2.1 times, and the opening shape is more regular (roundness error < 5%), meeting the damage requirements of ship compartments.

[0071] The specific implementation manners described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific implementation manners of the present invention and do not limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An efficient warhead material, characterized in that, It includes an outer structure of a steel-copper composite liner and a composite explosive filled inside the outer structure. The composite explosive includes a CL-20-based nano-thermite and 8701 explosive. The CL-20-based nano-thermite is Al@Ni core-shell particles.

2. An efficient warhead material according to claim 1, characterized in that, The steel-copper composite liner uses steel as the outer cover and copper as the inner cover. The thickness of the outer cover is 5.5 mm, and the thickness of the inner cover is 3.2 mm.

3. The high-performance warhead material according to claim 1, characterized in that Tungsten fibers with a BCC structure are implanted between layers of the CL-20-based nano-thermite. The diameter of the tungsten fibers is 200 nm, and the aspect ratio is 15:

1.

4. A charge combination design method for a high-performance warhead material as described in any one of claims 1-3, characterized in that, It includes the construction of a nano-gradient charge structure and the regulation of crystal structure.

5. The charge combination design method of a high-performance warhead material according to claim 4, characterized in that The nano-gradient charge structure is constructed such that the density or composition of the explosive varies in a gradient along a specific direction during charging. When charging, the density of the explosive increases from the outer layer to the inner layer. The density of the explosive in the outer layer is 1.75 g / cm 3 , and the density of the explosive in the inner layer is 2.15 g / cm 3 . The composition of the explosive varies in a gradient according to the ratio of CL-20-based nano-thermite to 8701 explosive.

6. The charge combination design method of a high-performance warhead material according to claim 5, characterized in that The orientation of the tungsten fibers is <111>.

7. The charge combination design method of a high-performance warhead material according to claim 5, characterized in that, The regulation of crystal structure includes the following steps: (1) Perform a surface scan on the CL-20-based nano-thermite crystal through SEM to obtain an orientation imaging map; (2) Use the texture analysis module to screen the proportion of the <010> crystal plane, and optimize the magnetic field parameters to make the orientation degree > 85%; (3) Verify the preferred distribution in the <001> direction through an inverse pole figure, and establish the coupling relationship between the crystal plane orientation and the detonation wave propagation; (4) Through the equal-channel angular pressing process, introduce a dislocation density gradient in the CL-20-based nano-thermite crystal to inhibit the crack propagation in the non-<001> direction.

8. The charge combination design method of a high-performance warhead material according to claim 7, characterized in that The coupling relationship in step (3) is calculated by the crystal plasticity-detonation dynamics multi-scale equation. The crystal plasticity-detonation dynamics multi-scale equation is: where x j is a spatial coordinate component, is a stress tensor component, ρ is the material density, is the material derivative of the acceleration, is the shear strain rate of the α-th slip system, is the unit vector in the slip direction of the α-th slip system, is the unit vector normal to the slip plane of the α-th slip system.

9. The charge combination design method of a high-performance warhead material according to claim 7, characterized in that The dislocation density gradient in step (4) is 1×10 14 m -2 to 5×10 14 m -2 .

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