Design method of energetic composite protective structure and protective structure

Abstract

The application provides a design method of an energetic composite protective structure and the protective structure, and the design method comprises the following steps: determining a jet penetration velocity change rate u according to a jet penetration mechanism; determining a reaction sensitivity g of a reaction material according to a reaction mechanism of the anti-penetration performance of the reaction material; determining a protection efficiency of the reaction material by judging the relative size of the velocity change rate u in the penetration process and the reaction sensitivity g of the reaction material; and designing the protective structure according to the protection efficiency of the reaction material. The protective structure comprises a protective layer shell, a reaction material shell and a reaction material layer arranged in sequence; and the reaction material layer is designed in a modular manner. The application has the advantages that: the violent chemical reaction of the reaction material under strong impact can be fully utilized to interfere with the penetration of the shaped jet, and the protection efficiency of the reaction material on the shaped jet is further improved by improving the reaction material formula, adding a reaction material constraint shell and other means.

Description

Technical Field

[0001] This invention relates to the field of protective structure design technology, specifically to a design method and protective structure for an energetic composite protective structure. Background Technology

[0002] Shaped charge projectiles, as a typical structure of shaped charge munitions, are extremely difficult to protect against due to their high velocity (traditional shaped charge projectile head velocities can reach 8000–10000 m / s) and large penetration depth (generally reaching 8–10 times the charge caliber). The main protective measures against shaped charge munitions include gap structure protection technology, ceramic composite armor protection technology, explosive reactive armor protection technology, and electromagnetic armor protection technology. These protective measures mainly have disadvantages such as increasing the thickness of the protective structure, introducing a certain degree of secondary hazard effects, and requiring bulky auxiliary equipment.

[0003] Reactive materials are energetic materials made from various non-explosive solid substances through specific methods. Under heating or high-speed impact conditions, they can react with air, either spontaneously or by interacting with it, releasing a large amount of chemical energy. Compared to traditional energetic materials such as TNT, reactive materials theoretically release more energy during reaction; some reactive materials can even release up to 1720 cal / cm³ of heat per unit volume, similar to TNT. 3 It is 3 to 4 times that of (l cal=4.186J). Common reaction material systems include: metal-oxide mixtures; metal-polymer mixtures; metal-metal mixtures, etc.

[0004] Currently, reactive materials are mainly used in the field of fragmentation warheads, replacing the inert fragments in traditional fragmentation warheads to form reactive fragments. This is because reactive materials generally have a higher density than traditional energetic materials, gaining greater kinetic energy upon penetrating the target. Relying on the vigorous chemical reaction and energy release of the reactive material under strong impact, reactive fragmentation warheads outperform traditional inert warheads in various applications. Reactive fragments possess both the "kinetic energy penetration" capability of traditional inert fragments and the ability to "release chemical energy" upon interaction with the target, thus achieving secondary damage to the target, especially effectively damaging weakly protected targets such as flammable and explosive materials, electronic equipment, and personnel. Simultaneously, in the field of lateral effect enhanced munitions, reactive materials can replace the inert core of traditional PELEs, undergoing a violent combustion and explosion reaction under high impact pressure to generate a large number of fragments for highly effective damage to armored targets. In addition, the material can replace the metal shaped charge liner of traditional shaped charge warheads to form a reactive jet that releases a large amount of chemical energy inside the target and causes multiple damage effects, thus merging the damage mechanism of a multi-stage warhead into a single-stage warhead.

[0005] Studies have also shown that reactive materials can be applied to the field of protective technology. Because reactive materials can undergo violent chemical reactions under the impact of fragments, their high temperature, high pressure and high speed reaction products will generate a reverse impulse on the projectile, reduce the axial kinetic energy of the fragments and play a protective role. Theoretically, the use of reactive materials in protective structures can effectively interfere with shaped charge jets, form further protection against the penetration of shaped charge munitions, and optimize the protective measures for shaped charge munitions.

[0006] However, at present, there are no specific applications of reactive materials in the field of protection. How to design protective structures containing reactive materials using systematic methods, how to maximize the protective efficiency of reactive materials, and how to evaluate their protective effects are all problems that urgently need to be solved. Summary of the Invention

[0007] To address the issues in the specific applications of reactive materials in the field of protection in existing technologies, this invention proposes a design method for an energetic composite protective structure.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a design method for an energetic composite protective structure, comprising the following steps:

[0009] S1. Determine the rate of change of the penetration velocity of the shaped jet based on the penetration mechanism of the shaped jet.

[0010] S2. Determine the reaction sensitivity g of the reactant material based on the reaction mechanism of its anti-penetration performance.

[0011] S3. Determine the magnitude of the rate of change of the penetration velocity of the shaped jet (ù) and the reaction sensitivity (g) of the reactive material. When ù and g are on the same order of magnitude, the reactive material can play a protective role against the penetration of the shaped jet.

[0012] S4. Design the protective structure based on the protective efficiency of the reactive materials.

[0013] Furthermore, when the rate of change of the penetration velocity of the focused jet in step S3 is less than the reaction sensitivity g of the reactant material, it is necessary to improve the energy release characteristics of the reactant material, specifically including the following methods:

[0014] S31. Select different types of reaction materials;

[0015] S32. Adjust the composition of the reaction materials;

[0016] S33. Optimize the preparation process of reaction materials;

[0017] S34. Add reactive material to constrain the shell.

[0018] Furthermore, in step S1, determining the rate of change of the penetration velocity of the shaped jet requires calculating the jet penetration depth and penetration velocity based on fluid dynamics theory, and combining the variation law of the penetration process with the time scale to determine the rate of change of the penetration velocity. The value of the rate of change of velocity ù is used to determine the rapid change zone and the attenuation zone of the penetration rate of the shaped jet.

[0019] The formula for predicting jet penetration depth is:

[0020]

[0021] The formula for predicting jet penetration velocity is:

[0022]

[0023] Where l is the length of the focused jet, ρ j For the density of the shaped jet, V j The velocity of the focused jet, ρ t The density of the target.

[0024] Furthermore, when the penetration rate of the shaped jet is in the rapidly changing region, and the reaction degree of the reactive material reaches its maximum value range, the reactive material will achieve the best protective effect against the penetration of the shaped jet.

[0025] Furthermore, in step S2, g represents the time required for the reactant material to complete the ultrafast reaction; the determination of g requires reference to the impact-induced reaction model of the reactant material to determine the reaction sensitivity of the reactant material. g also requires reference to the impact-induced reaction model of the reactant material to calculate the reaction threshold of the reactant material. The empirical prediction formula for the PTFE / AL impact-induced reaction can be found at:

[0026]

[0027] Where A and B are undetermined parameters, and σ T For the stress threshold of the reactive material, The strain rate threshold of the reactive material, σ, These represent the impact stress and loading strain rate under the test conditions, respectively.

[0028] Furthermore, in step S31, the reaction material is preferably a metal-oxide mixture reaction material.

[0029] Furthermore, after determining the optimal protective material for the shaped jet in step S32, the components in the reaction material that have a significant impact on the penetration rate and structural strength of the shaped jet are optimized and adjusted. The reaction material formulation with the best protective effect against the shaped jet is obtained through experimental verification. The reaction material components include two or more combinations of different metal particles, or two or more combinations of metal particles and metal oxides, or two or more combinations of metal particles and polymers.

[0030] Furthermore, the reaction material preparation process in step S33 includes: pretreatment of the reaction material, material forming, and post-treatment of the billet; the pretreatment process mainly targets the modification of each component of the reaction material to change the reaction activation energy and reaction threshold temperature of the reaction material; the material forming process mainly affects the impact ignition reaction threshold of the material; the post-treatment process of the billet is used to refine the microstructure of the reaction material and eliminate dislocations and twin defects inside the material.

[0031] Furthermore, in step S34, a reactive material constraint shell is added. The constraint shell material is selected from steel, plastic, or composite materials. The constraint shell is used to cut off the shaped jet and reduce the penetration capability of the shaped jet, so as to improve the energy utilization rate of the reactive material and the protection efficiency against the shaped jet.

[0032] This invention also provides a reactive material protective structure, designed according to the above-mentioned design method of energetic composite protective structure. The protective structure is provided with a protective shell, a reactive material shell, and a reactive material layer in sequence. The reactive material layer adopts a modular design, and the size of a single reactive material layer module is set to 3 to 5 times the diameter of the incoming focused jet. The reactive material shell and the reactive material layer are formed by splicing modules. After a single module is damaged, it can be quickly replaced, realizing the efficient utilization of the reactive material layer.

[0033] The advantages of this invention are: it proposes a design method for using reactive materials in the protective structure of shaped-charge jets, which can fully utilize the energy released by the violent chemical reaction of the reactive materials under strong impact to interfere with the shaped-charge jet, thereby improving the protective efficiency of the reactive materials against shaped-charge jets and reducing potential secondary hazards. In the provided protective structure incorporating reactive materials, the reactive material layer is modularized according to the size of the damage area after impact with the target, and assembled accordingly. Individual modules can be quickly replaced after being damaged, achieving efficient utilization of the reactive material layer. Attached Figure Description

[0034] Figure 1 This is a flowchart of the composite protective design method for reactive materials according to the present invention;

[0035] Figure 2 This is a schematic diagram of the jet penetrating the target.

[0036] Figure 3A typical characteristic diagram of the penetration process of a shaped charge warhead;

[0037] 3a shows the variation of penetration depth and penetration velocity over time, and 3b shows the variation of penetration velocity over penetration depth.

[0038] Figure 4 This diagram shows the pressure distribution at the front of the shock wave when a copper sheet impacts a mixture of Ni particles and spherical Al particles.

[0039] 4a is the pressure distribution diagram of spherical Ni particles, and 4b is the pressure distribution diagram of Al particles;

[0040] Figure 5 This is the protective structure for the reaction material of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0042] This invention is based on the high-speed penetration mechanism of shaped charge jets. It makes full use of the violent reaction that occurs in a local area (3-5 times the diameter of the projectile) when the reactive material is penetrated, and rapidly and violently releases a large amount of gas (significantly increasing the overpressure near the detonation point) and heat value (instantaneous temperature exceeding 3000K), which further interferes with the penetration of the shaped charge jet, thereby achieving effective protection of the target.

[0043] The main approach is to install a reactive material layer of a certain thickness on the surface of the protective structure. This balances the rate of change of the shaped jet penetration velocity with the reactive material's sensitivity, maximizing the material's optimal protective efficiency. The design of the reactive material layer requires comprehensive consideration of the shaped jet's penetration characteristics and the material's impact reaction mechanism to determine its optimal protective efficiency, and then design the reactive material protective structure accordingly.

[0044] like Figure 1 As shown, the reactive material composite protection design method of the present invention is as follows:

[0045] S1. Determine the jet penetration velocity variation rate ù based on the energy-concentrated jet penetration mechanism;

[0046] S2. Determine the reaction sensitivity g of the reaction material based on its protective mechanism;

[0047] S3. Determine the magnitude of the rate of change of the penetration velocity of the shaped jet (ù) and the reaction sensitivity (g) of the reactive material. When ù and g are on the same order of magnitude, the reactive material can play a protective role against the penetration of the shaped jet.

[0048] S4. Design the protective structure based on the protective efficiency of the reactive materials.

[0049] The determination of the velocity change rate during the penetration process of the focused jet in step S1 is based on the fluid dynamics theory of high-speed penetration of the jet into the metal target.

[0050] Based on the high-speed jet penetration theoretical model established by Brikhoff et al., both the metal jet and the target are considered as ideal incompressible fluids. The high-speed penetration of the jet into the target generates extremely high collision pressure, which allows the strength of the jet and the target to be approximately ignored in theoretical analysis. A schematic diagram of the jet penetration into the target is shown below. Figure 2 As shown. The coordinate system is established at the collision point A, and the velocity of the shaped charge penetrator is v. j The penetration velocity is μ, and the target velocity on the moving coordinate system is -μ. During the jet penetration of the target, the pressure balance relationship at the jet / target interface along the projectile-target centerline can be described by the Bernoulli equation:

[0051]

[0052] Where (p) j ) -∞ The pressure of the focused jet at an infinite distance from point A, (p t ) ∞ Let ρ be the pressure on the target at an infinite distance from A, and both can be ignored. j For the density of the shaped charge penetrator, ρ t Given the density of the target, formula (1) becomes:

[0053]

[0054] Let the length of the uniformly oriented focused jet be l, and the total armor-piercing time be t, then:

[0055]

[0056] Penetration depth is:

[0057] L = ut (4)

[0058] Formulas (2), (3), and (4) can be used to derive the formula for predicting the jet penetration depth based on fluid dynamics theory:

[0059]

[0060] After determining the depth of jet penetration, the rate of change of jet penetration velocity is determined based on the variation of the penetration process over time. For example... Figure 3The diagram shows typical characteristics of the penetration process of a shaped charge warhead. During penetration, the rapid change zone and attenuation zone of the shaped charge jet's penetration rate are determined based on the changes in penetration depth and penetration velocity over time. When the position and thickness of the reactive material cause the shaped charge jet's penetration rate to fall within the rapid change zone, impacting the detonating reactive material can interfere with the penetration of the shaped charge jet, rapidly reducing its penetration depth and achieving optimal protection. The rate of change of the penetration velocity during the shaped charge jet's penetration of the target is represented by ù.

[0061] from Figure 3 It can be seen that the entire process of a shaped charge jet penetrating a target is generally on the order of milliseconds, and the duration of the rapid change zone in the penetration rate is basically maintained at around 200 μs. It can be determined that the time scale of the main process of penetration of shaped charge warheads is basically on the order of hundreds of microseconds.

[0062] The determination of the reaction sensitivity g of the reaction material in step S2 is derived based on the protection mechanism of the reaction material.

[0063] Firstly, the process of chemical changes induced by impact on reacting materials needs to be referenced in the Graham impact-induced chemical reaction model. This model divides the impact compression process into three states: the unreacted material state, the initial state under high pressure, and the compression state in the transition zone. The transition zone explains that the chemical reaction begins at the shock wave front, and its entire process includes material micromorphological deformation, mixing, impact activation, and exothermic behavior. Among these, micromorphological deformation refers to changes in the size, shape, and distribution of the phases; mixing describes changes in the boundaries between reactants; impact activation refers to the increase in atomic mobility due to the increase in internal defects and friction on defect surfaces; and exothermic behavior refers to the temperature rise caused by heat release from volume compression, energy localization near pores or defects, and thermal transport processes.

[0064] Generally, based on the magnitude of the impact load on the reacting material, its impact chemical reaction can be divided into two categories: ultrafast reactions, which occur during high-pressure compression of the material (reaction timescales range from a few nanoseconds to tens of microseconds); and slow reactions (reaction timescales typically range from tens of microseconds to a few milliseconds), which occur over a longer period after unloading from the high-pressure state. Eakins et al. presented the pressure distribution at the shock wave front of spherical Ni-Al mixed particles (4a) and plate-like Ni + spherical Al mixed particles (4b), such as... Figure 4 As shown.

[0065] It can be seen that the reaction time of the shock wave front of the reactant material under the action of external load is relatively short. It can react rapidly within tens of ns after being subjected to the impact load. The sensitivity of the reactant material to the action of external impact is represented by g. In terms of quantitatively describing the reaction sensitivity of the reactant material, g represents the time for the reactant material to complete the ultrafast reaction.

[0066] Since the timescale of the entire penetration process of the shaped jet is basically on the order of μs, when the rate of change of the penetration velocity of the shaped jet ù is on the same order of magnitude as the reaction sensitivity g of the reactive material, the reactive material can play a protective role against the penetration of the shaped jet, thus ensuring that the principle and method of using the reactive material to interfere with the penetration of the jet are feasible.

[0067] Secondly, it is also necessary to analyze and judge the impact energy release behavior of the reactive materials based on the reaction threshold of the reactive materials.

[0068] The impact energy release behavior of reactive materials involves complex mechanical-thermal-chemical coupling. The impact reaction induction mechanism, critical conditions, and prediction of such materials remain key research areas requiring further investigation. Under impact compression or strong dynamic loading, reactive materials undergo processes such as plastic deformation, microjets, fragmentation, and micropore collapse. Consequently, rapid mixing of material particles occurs behind the shock wave front, ultimately leading to temperature increases and the fusion of components within the material, resulting in a chemical reaction.

[0069] The chemical reaction process caused by the impact of reactive materials can be divided into three processes: the triggering of the reaction, the propagation and the expansion of the reaction. The impact compression of reactive materials is closely related to the particle collision and deformation, mass transport, temperature distribution, occurrence and development of chemical reactions and material dynamic properties (density, pressure, shock wave, etc.) at the meso / micro scale. Among these, the collision velocity or collision pressure that induces the reaction of the material is usually used as the criterion for the induction of the impact reaction of the material. Based on this, Ge Chao et al. proposed an empirical formula for the impact reaction threshold of PTFE / Al reactive materials based on the impact pressure and the loading strain rate, as shown in formula (6).

[0070]

[0071] Where A and B are undetermined parameters, and σ T For the stress threshold of the reactive material, The strain rate threshold of the reactive material, σ, These represent the impact stress and loading strain rate under the test conditions, respectively. Formula (6) gives the reaction threshold of the PTFE / Al reactive material under normal impact conditions, which must simultaneously reach σ. T =735MPa and Considering that the collision pressure generated during the interaction between the shaped jet and the target is generally on the order of GPa and the strain rate range is greater than 10, 5 s -1 Therefore, under the high-speed impact of the focused jet, the reactive materials will undergo a certain degree of reaction.

[0072] Based on the experimental results of ultra-high speed impact of aluminum alloy projectiles on PTFE / A1 reactive materials, Wu Qiang et al. proposed a dimensionless empirical formula for the damage area of ​​the reactive material structure under ultra-high speed impact of spherical projectiles, as shown in formula (7).

[0073]

[0074] In formula (7), D b The diameter of the perforation in the reactive material by the projectile, d p For the projectile diameter, v p For the projectile impact velocity, ρ b For the density of the projectile material, σ b For the yield strength of the material, t b The thickness of the reactive material is given. Formula (7) can be used to calculate the damage range of the hypervelocity penetration reactive material, which is approximately 3 to 5 times the diameter of the projectile. This data can be used as the basis for the smallest unit of modular design of the reactive material.

[0075] Therefore, to ensure that the rate of change of the shaped jet penetration velocity ù is on the same order of magnitude as the reaction sensitivity g of the reactive material, and to achieve the optimal protective efficiency of the reactive material in the protective structure, it is necessary to judge and select the material based on its own characteristics. This includes the following aspects:

[0076] ① Select different types of reaction materials.

[0077] Currently, there are relatively many types of reactive materials, mainly including three categories: metal-oxide mixtures, metal-polymer mixtures, and metal-metal mixtures. For all reactive material systems, reactive metal particles, or metal fuels (Al, Mg, Zr, etc.), are an essential component. Al powder possesses excellent comprehensive properties, including high heat release per unit volume, ease of powder engineering preparation, high safety, and low cost. In particular, it exhibits good reactivity when mixed with most metals, nonmetals, oxides, and polymers. Therefore, Al has always been the most commonly used metal component in various reactive material systems.

[0078] For metal-oxide mixtures, typical examples include Al-Fe₂O₃ and Al-MnO₂; for metal-polymer mixtures, typical examples include Al-PTFE and Ta-THV; and for metal-metal mixtures, typical examples include Al-Ni, Al-Ti, Al-Fe, and multi-metal mixtures. Currently, metal-polymer reactive materials are the most studied due to their high energy content and simple processing. However, their density and strength are generally low, limiting their application, especially against high-speed penetration of shaped jets, where their strength significantly affects the jet's penetration capability. In contrast, metal-metal reactive materials generally have much higher density and strength, and can be used not only as energetic materials but also as structural materials. Therefore, metal-metal reactive materials should be the preferred protective material against shaped jets.

[0079] ② Adjust the composition of the reaction materials.

[0080] Reactive materials typically consist of two or more non-explosive solid materials, generally including combinations of two or more metal particles (Al, Mg, Zr, etc.), metal particles and metal oxides (Fe2O3, CuO, MoO3, etc.), or polymers (PTFE, TVH, etc.). They remain inert during normal handling and storage, but undergo chemical reactions and release energy when subjected to strong impact loading, producing effects such as combustion or detonation. After determining the type of reactive material for shaped charge protection, each component in the reactive material that significantly affects the core parameters of its anti-jet penetration performance, such as reaction rate and structural strength, is optimized and adjusted. Experimental verification yields the reactive material formulation with the best protective effect against shaped charge jets.

[0081] ③ Optimize the preparation process of reaction materials.

[0082] The key to realizing the engineering application of reactive materials lies in ensuring that the materials possess excellent reactive energy release characteristics (including reaction temperature threshold, reaction rate, and heat release per unit volume), while also considering the material's physical properties such as density and strength to guarantee its resistance to penetration during projectile attack. Furthermore, factors such as safety, cost, and forming efficiency must also be considered. Therefore, the selection of the material preparation process is crucial, encompassing the pretreatment of the reactive materials, material forming, and post-processing of the blank. Different processes have their own characteristics and applicable ranges, and can be flexibly selected during material preparation based on the reactive materials' resistance to shaped charge jet penetration.

[0083] The pretreatment process of the reactive materials mainly involves modifying the reactive materials of each component, which can change key parameters such as the reaction activation energy and reaction threshold temperature. This mainly includes reaction-limited ball milling and sol-gel methods. The material forming process directly affects the impact ignition reaction threshold of the material. Different material forming processes should be selected for different types of reactive materials, including cold pressing, explosive forming, physical vapor deposition, multi-pass stacking, dynamic spraying, and extrusion forming. The post-treatment process of the billet can refine the material structure, eliminate a large number of dislocations, twins and other defects inside the reactive materials, improve the contact degree of each component, and increase the combustion rate.

[0084] ④ Add reactive materials to constrain the shell.

[0085] Adding a reactive material to the confining shell can improve the energy utilization rate of the reactive material and enhance its protection efficiency against shaped jets.

[0086] The shell further constrains and controls the energy release behavior of the reactive material, enhancing its interference with the penetration of the shaped charge jet. The optimal shell material and thickness can be determined through target-firing experiments involving shaped charge jets penetrating reactive materials with shells of varying thicknesses. Furthermore, the effects of adding a shell and increasing the reactive material layer thickness on the reactive material's reaction characteristics are consistent; therefore, while optimizing the shell thickness, adjustments to the reactive material layer thickness can also be considered. In addition, the reactive material can reverse-drive the shell's movement during the reaction, further hindering the shaped charge jet's penetration and reducing its penetration capability.

[0087] Based on the above steps, the optimal way for the reactive material to achieve its protective efficiency can be determined, which can then be used to design a highly efficient protective structure for the reactive material.

[0088] The present invention also provides a protective structure for reactive materials, such as Figure 4 As shown, the protective structure consists of a protective shell 1, a reactive material 2, and a reactive material shell 3, arranged from right to left. The reactive material shell 3 improves the energy utilization rate of the reactive material and enhances its protection efficiency against shaped charge jets. The shell material can be steel, plastic, composite materials, etc., and its thickness and shape can be confirmed through target testing of shaped charge jets penetrating reactive material layers with shells of different thicknesses. The reactive material layer 2 and the reactive material shell 3 can be configured as individual modules, 3 to 5 times the diameter of the penetrating projectile, and assembled into the protective shell 1 to achieve efficient utilization of the reactive material.

[0089] In conjunction with the reactive material composite protection design method of the present invention, when facing the penetration of a shaped jet, the penetration velocity of the shaped jet impacts and detonates the reactive material when passing through the protective layer shell 1 and the reactive material shell 3. After the reactive material reacts, it can interfere with the penetration of the jet, thereby achieving effective protection of the target.

[0090] The above description is merely the preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A design method for an energetic composite protective structure, characterized in that, Includes the following steps: S1. Determine the rate of change of the penetration velocity of the shaped jet based on the penetration mechanism of the shaped jet. S2. Determine the reaction sensitivity g of the reactant material based on the reaction mechanism of its anti-penetration performance. S3. Determine the relationship between the rate of change of the shaped jet penetration velocity (ù) and the reaction sensitivity (g) of the reactive material. When ù and g are on the same order of magnitude, the reactive material can provide protection against the penetration of the shaped jet. When the rate of change of the shaped jet penetration velocity (ù) is less than the reaction sensitivity (g) of the reactive material, the energy release characteristics of the reactive material need to be improved. Specific methods include the following: S31. Select different types of reaction materials; S32. Adjust the composition of the reaction materials; S33. Optimize the preparation process of reaction materials; S34. Add reactive materials to constrain the shell; S4. Design the protective structure based on the protective efficiency of the reactive materials; After determining the optimal protective material for shaped jets in step S32, the components of the reactive material that have a significant impact on the penetration rate and structural strength of the shaped jets are optimized and adjusted. The reactive material formulation with the best protective effect against shaped jets is obtained through experimental verification. The reactive material formulation includes two or more combinations of different metal particles, or two or more combinations of metal particles and metal oxides, or two or more combinations of metal particles and polymers.

2. The design method of the energetic composite protective structure according to claim 1, characterized in that, In step S1, determining the rate of change of the penetration velocity of the shaped jet requires calculating the penetration depth and penetration velocity based on fluid dynamics theory, and combining the variation law of the penetration process with the time scale to determine the rate of change of the penetration velocity. The value of the rate of change of velocity ù is used to determine the rapid change zone and the attenuation zone of the penetration rate of the shaped jet. The formula for predicting jet penetration depth is: The formula for predicting jet penetration velocity is: in For the length of the focused jet, For the density of the focused jet, For the velocity of the focused jet, The density of the target.

3. The design method of the energetic composite protective structure according to claim 2, characterized in that, When the penetration rate of the shaped jet is in the rapidly changing region, and the degree of reaction of the reactive material reaches its maximum value range, the reactive material will achieve the best protective effect against the penetration of the shaped jet.

4. The design method of the energetic composite protective structure according to claim 1, characterized in that, In step S2, g represents the time required for the reactant material to complete the ultrafast reaction. Determining g requires referring to the impact-induced reaction model of the reactant material and calculating its reaction threshold. The empirical prediction formula for the PTFE / AL impact-induced reaction is as follows: Where A and B are parameters to be determined. For the stress threshold of the reactive material, The strain rate threshold of the reactive material, σ, These represent the impact stress and loading strain rate under the test conditions, respectively.

5. The design method of the energetic composite protective structure according to claim 1, characterized in that: In step S31, the preferred reaction material is a metal-oxide mixture.

6. The design method of the energetic composite protective structure according to claim 1 or 5, characterized in that, The reaction material preparation process in step S33 includes: pretreatment of the reaction material, material forming, and post-treatment of the billet; the pretreatment process mainly modifies each component of the reaction material to change the reaction activation energy and reaction threshold temperature of the reaction material; the material forming process mainly affects the impact ignition reaction threshold of the material; the post-treatment process of the billet is used to refine the microstructure of the reaction material and eliminate dislocations and twin defects inside the material.

7. The design method of the energetic composite protective structure according to claim 1 or 5, characterized in that, In step S34, a reactive material constraint shell is added. The constraint shell material is selected from steel, plastic, or composite materials. The constraint shell is used to cut off the shaped jet and reduce the penetration capability of the shaped jet, so as to improve the energy utilization rate of the reactive material and the protection efficiency against the shaped jet.

8. A reactive material protective structure, designed according to the design method of an energetic composite protective structure as described in any one of claims 1 to 7, characterized in that, The protective structure is provided with a protective shell, a reactive material shell, and a reactive material layer in sequence. The reactive material layer adopts a modular design, with the size of a single reactive material layer module set at 3 to 5 times the diameter of the incoming focused jet. The reactive material shell and reactive material layer are formed by splicing modules together. If a single module is damaged, it can be quickly replaced, realizing the efficient utilization of the reactive material layer.

Images