Method and device for determining the destruction of a layered protective structure based on a virtual explosive source
By constructing an equivalent explosion load model using the virtual explosion source method, the problem of determining the damage effect of layered protective structures under kinetic energy penetrating projectile attacks is solved, enabling accurate assessment of the damage state of the protective structure and improving the effectiveness and accuracy of the assessment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF TECH
- Filing Date
- 2026-02-05
- Publication Date
- 2026-05-29
AI Technical Summary
Layered protective structures are difficult to accurately determine the collapse damage effect under conventional kinetic energy bunker-buster attacks, and existing technologies cannot effectively assess their degree of damage.
An equivalent explosion load model was constructed using the virtual explosion source method. The failure state of the protective structure was determined by evaluating the entire process of penetration-explosion-wave propagation-structural response, combined with the stress wave propagation model and critical collapse thickness calculation.
It improves the accuracy and effectiveness of assessing the damage effects on layered protective structures, and can systematically determine the damage status of the main support layer, thereby enhancing the effectiveness and accuracy of the assessment.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of protection technology, and in particular to a method and apparatus for determining the damage of a layered protective structure based on a virtual explosion source. Background Technology
[0002] Layered protective structures are used to defend against conventional kinetic energy bunker-buster projectiles, protecting the target from destruction. During the entire destruction process, the powerful shockwave generated by the explosion of the explosive charge inside the conventional kinetic energy bunker-buster projectile, along with the strong force of the detonation products on the surrounding medium, causes varying degrees of damage to the back of the supporting structure.
[0003] Because the failure process involves the coupling of multiple physical processes and the transmission and reflection effects of stress wave interfaces, it is difficult to determine the collapse failure effect of layered protective structures. Summary of the Invention
[0004] The purpose of this invention is to provide a method and apparatus for determining the damage of layered protective structures based on virtual blast sources, so as to solve one of the technical problems of the difficulty in determining the collapse damage effect and poor accuracy of layered protective structures.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] In a first aspect, embodiments of the present invention provide a method for determining the damage of a layered protective structure based on a virtual explosion source, comprising: The incident velocity of the projectile and the thickness of each layer of the protective structure are obtained, wherein the protective structure includes, from the outside to the inside, a projectile shielding layer, a dispersion layer and a main support layer; Based on the incident velocity of the projectile and the thickness of the corresponding layer, it is determined that the projectile is embedded in the corresponding layer of the protective structure; If the projectile is embedded in the main support layer and the projectile's blast center is located in the main support layer, the protective structure is determined to be damaged. If the projectile is embedded in the shielding layer or the dispersion layer, calculate the first stress wave peak value at the top of the main support layer; use the virtual explosion source method to treat the projectile as if it exploded in a preset structure, and determine the position of the virtual explosion source in the preset structure based on the first stress wave peak value; determine whether the protective structure is damaged based on the position of the virtual explosion source in the preset structure and the thickness of the main support layer; wherein, the preset structure is formed of the same material as the main support layer.
[0007] According to at least one embodiment of the present invention, determining the location of the virtual explosion source in the preset structure based on the first stress wave peak value includes: In the preset structure, when the first stress wave peak is generated directly below the virtual explosion source, the first distance between the virtual explosion source and the location of the generated first stress wave peak is defined as follows:
[0008] According to at least one embodiment of the present invention, when the projectile is equivalent to detonating in a preset structure using a virtual explosion source method, the method further includes: When the virtual explosion source detonates in the preset structure, the critical collapse thickness at which the preset structure collapses is calculated.
[0009] According to at least one embodiment of the present invention, it is determined whether the protective structure is damaged based on the first distance, the thickness of the main support layer, and the critical collapse thickness.
[0010] According to at least one embodiment of the present invention, if the sum of the first distance and the thickness of the main support layer is less than the critical collapse thickness, it is determined that the protective structure is damaged; otherwise, it is determined that the protective structure is not damaged.
[0011] According to at least one embodiment of the present invention, the critical collapse thickness h when the preset structure collapses is... r satisfy: , in, Explosion parameters related to burial depth; These are the explosion parameters related to the aspect ratio; This is the equivalent of an exposed explosive charge. This refers to the length parameter of the projectile's head. is the elastic modulus of concrete, in MPa; is the axial compressive strength of concrete, in MPa; The density of concrete is expressed in kg / m³. 3 ; Let m be the structural parameter.
[0012] According to at least one embodiment of the present invention, calculating the first stress wave peak value at the top of the main support layer includes: Based on the interface layer stress wave propagation model, the peak value of the first stress wave at the top of the main support layer is calculated.
[0013] According to at least one embodiment of the present invention, the stress wave propagation model satisfies: , Among them, P r The peak stress (MPa) is the stress exerted by the explosion on the bottom of the corresponding layer directly below the explosion center. The equivalent TNT weight of the projectile is expressed in kg. The distance, in meters, is the distance between the bottom of the corresponding layer into which the projectile is embedded, and the center of the explosion. This is the coefficient for the depth of the explosive charge. The attenuation coefficient; This is the decay index.
[0014] According to at least one embodiment of the present invention, the position of the detonation center is calculated based on the structural parameters of the projectile, satisfying: , Among them, H qb H is the distance from the center of the projectile to the top surface of the shielding layer after the projectile has penetrated the protective structure, in meters; H is the penetration depth of the projectile in the protective structure, in meters; l is the length of the projectile, in meters; K is the distance from the center of the projectile to the top surface of the shielding layer, in meters. b β is the deflection coefficient of the projectile in the material; β is the impact angle of the projectile.
[0015] Secondly, embodiments of the present invention provide a damage determination device for a layered protective structure based on a virtual explosion source, used in the damage determination method described in the first aspect. In one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.
[0016] The exemplary embodiment of this invention provides a method for determining the damage of a layered protective structure based on a virtual explosion source. The layered protective structure specifically includes a projectile shielding layer, a dispersion layer, and a main support layer arranged sequentially from the outside in. Based on the projectile's incident velocity and the thickness of each layer of the protective structure, the projectile's penetration and embedding in one of the projectile shielding layer, dispersion layer, or main support layer can be calculated. When it is calculated that the projectile is embedded in the innermost main support layer, and the projectile's explosion center is located within the main support layer, then the protective structure can be determined to be damaged.
[0017] Furthermore, if the projectile is embedded in a shielding layer or a dispersion layer, the first stress wave peak value at the top of the main support layer needs to be calculated based on the stress wave propagation model and the material properties of each layer. Subsequently, the projectile is treated as if it exploded within a pre-defined structure using a virtual explosion source method, where the pre-defined structure is made of the same material as the main support layer. The location within the pre-defined structure where the first stress wave peak value is generated directly below the virtual explosion source is calculated, thus determining the first distance between the virtual explosion source and this location. Simultaneously, the critical collapse thickness of the pre-defined structure is calculated using the virtual explosion source method. Based on this, when the sum of the first distance and the thickness of the main support layer is less than the critical collapse thickness, the protective structure is determined to be damaged; otherwise, the protective structure is determined to be intact.
[0018] Furthermore, by assessing the anti-damage capability of penetration-explosion-wave propagation-structural response, the damage effect on the main support layer of the protective structure under conventional kinetic energy bunker-buster projectile strikes is systematically and comprehensively determined, thereby improving the effectiveness and accuracy of the assessment. Attached Figure Description
[0019] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.
[0020] Figure 1 This is a flowchart illustrating the method for determining the damage of a layered protective structure based on a virtual explosion source according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the damage to the protective structure under the impact of a bunker-buster projectile according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the final position of the projectile when it penetrates and embeds into the protective structure and explodes, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the critical collapse thickness calculation process according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the calculation process of the penetration depth and blast center position of the projectile in different layers according to an embodiment of the present invention. Detailed Implementation
[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0022] Figure 2 This is a schematic diagram illustrating the damage to the protective structure under the impact of a bunker-buster projectile according to an embodiment of the present invention. Figure 2 As shown, the protective structure is generally located within the soil and rock layer, and consists of a shielding layer, a dispersion layer, and a main support layer from the outside in. This structure is called a layered protective structure or composite structure, and the material properties and thickness of each layer are designed according to the protection requirements. When a bunker-buster projectile strikes this protective structure, the main process involves first using the projectile's own kinetic energy to penetrate to a specific location or maximum penetration depth of the target, and then detonating the high-energy explosive loaded inside. The damage primarily relies on the shock wave and detonation products generated by the projectile's explosive charge to exert a powerful force on the surrounding medium, causing cracks, spalling fragments, or collapse on the back of the main support layer.
[0023] However, the damage evolution mechanism is complex and the degree of damage is difficult to determine accurately because the penetration process involves the nonlinear response of materials, the transmission and reflection effects of stress waves at the interlayer interface, and the coupling effect of multiple physical fields.
[0024] To address the aforementioned problems, an exemplary embodiment of the present invention proposes a method for determining the damage of layered protective structures based on the virtual blast source method. By constructing an equivalent explosion load model, the entire process of penetration-explosion-wave propagation-structural response is systematically and completely evaluated, thereby accurately determining the collapse damage effect of layered protective structures.
[0025] It should be noted that, for ease of description, the protective structure mentioned in this article is also referred to as the target, and the blast center refers to the position of the geometric center of the explosive charge when the projectile explodes.
[0026] Example 1 Figure 1 This is a flowchart illustrating a method for determining the damage of a layered protective structure based on a virtual explosion source, according to an embodiment of the present invention. Figure 1 As shown, the damage determination method for a layered protective structure based on a virtual explosion source according to an exemplary embodiment of the present invention includes the following steps: Step 101: Obtain the incident velocity of the projectile and the thickness of each layer of the protective structure. The protective structure, from the outside in, includes a shielding layer, a dispersion layer, and a main support layer, as follows: Figure 2 As shown.
[0027] Figure 5 This is a schematic diagram illustrating the calculation process of the projectile's penetration depth and detonation point in different layers according to an embodiment of the present invention. Figure 5 As shown, the moment the projectile encounters the protective structure is called a hit. The initial velocity of the projectile at the instant of contact with the protective structure is V0, and the angle of impact is β, which is the angle between the axis of the projectile and the surface of the protective structure. Assuming that no ricochet occurs when the projectile encounters the protective structure, the subsequent penetration effect calculation is carried out based on the projectile-target encounter conditions.
[0028] The thickness of the shielding layer is denoted as H. zd The thickness of the dispersion layer is expressed as H. fs The thickness of the main support layer is expressed as H. zt .
[0029] Step 102: Determine the appropriate layer into which the projectile is embedded in the protective structure based on the incident velocity of the projectile and the thickness of the corresponding layer.
[0030] The penetration path, penetration depth, and maximum velocity of the projectile in each layer were calculated using Young's formula.
[0031] Young's formula is: ;Formula 1; in, ; ; ; In the formula, Hi q represents the penetration distance of the projectile head through the shielding layer, dispersion layer, or main support layer, respectively, and i represents zd, fs, and zt, respectively; K(m p ) is the quality correction factor; K(m) p )=Am p B ; where m p A is the mass of the projectile, in kg; A is the area of the projectile's cross-section, in m². 2 ; N is the projectile head shape factor, where N = 0.18l for an oval projectile head. n / d+0.56 or N=0.18(CRH-0.25) 2 +0.56; Conical projectile head, take N=0.18l n / d+0.56; For the truncated oval projectile head, take N=0.09(l) n +l n ) / d+0.56;l n d is the projectile head length (m); d is the projectile diameter (m); CRH is the projectile head radius ratio; l n is the length of the projectile's nose section without a truncated section, in meters; V0 is the initial penetration velocity of the projectile, in m / s; F(V0) is a velocity-related term; K e For correction factor, W is the dimensionless width of the target plate, which is a multiple of the projectile diameter. If W > F, then K is taken. e =1, for plain concrete F=30, for reinforced concrete F=20, for thin target (T c =0.5~2), the value of F should be reduced by 50%; T c The dimensionless thickness of the protective structural layer is a multiple of the projectile diameter, T c >0.5, if T c >6, then take T c =6; P is the volumetric reinforcement ratio of the protective structural layer, % J(P) is the reinforcement ratio correction term; f c The uniaxial compressive strength of the concrete for the protective structural layer, in MPa; C J When the protective structural layer contains reinforcing steel, the strength of the reinforcing steel affects the penetration stroke H. i q The influence coefficient, for ordinary steel reinforcement, C J =1, for ultra-strong steel reinforcement, C J =0.92.
[0032] Figure 3 This is a schematic diagram showing the final position of the projectile when it penetrates and embeds into the protective structure and explodes, according to an embodiment of the present invention. Figure 3 As shown, based on the projectile's structural parameters and considering the influence of the projectile's length, the formula for calculating the explosive charge's detonation point is as follows: Formula 2; Among them, H qb The detonation point of the explosive charge is the distance, in meters, between the geometric center of the explosive charge inside the projectile and the surface of the shielding layer after the projectile has penetrated the protective structure. H is the penetration depth of the projectile in the protective structure, in meters; l is the length of the projectile, in meters; K b The deflection coefficient of the projectile in the material is shown in Table 1; β is the projectile's angle of impact (°).
[0033] Table 1. Deflection coefficients of the projectile
[0034] Continue as Figure 5 As shown, the calculation of the projectile's penetration depth and detonation point in different layers includes: (1) Calculate the travel H of the projectile's head in the shielding layer using Young's formula. zdq The thickness of the projectile penetration is H. zd The limit velocity V of the shielding layer BL1 .
[0035] If V 01 <V BL1 If the projectile's head embeds into the shielding layer but does not penetrate the dispersion layer, the projectile's penetration depth H and the detonation point H of the explosive charge can be calculated using a formula. qb .
[0036] ; According to Equation 2, we can obtain: .
[0037] (2) If V 01 >V BL1 If the projectile's head penetrates the shielding layer and enters the dispersion layer, calculate the remaining velocity V of the projectile after penetrating the shielding layer. r1 And use it as the initial velocity V for penetrating the dispersion layer. 02 .
[0038] in, ; The dispersion layer was calculated using the same method as in step (1), and the travel distance H of the projectile head in the dispersion layer was obtained.fsq The thickness of the projectile penetration is H. fs The limit velocity V of the shielding layer BL2 .
[0039] If V 02 <V BL2 If the projectile's head is embedded in the dispersion layer but does not penetrate the main support layer, the projectile's penetration depth H and the explosive charge's detonation position H can be calculated using the formula. qb .
[0040] ; According to Equation 2, we can obtain: .
[0041] (3) If V 02 >V BL2 If the projectile's head penetrates the dispersion layer and enters the main support layer, calculate the remaining velocity V of the projectile after penetrating the dispersion layer. r2 V, as the initial velocity V for penetrating the dispersion layer 03 .
[0042] in, ; If V 03 <V BL3 If the projectile's head is embedded in the main support layer but does not penetrate the protective structure, the projectile's penetration depth H and the explosive charge's detonation position H can be calculated using formulas. qb .
[0043] ; According to Equation 2, we can obtain: ; Step 103: If the projectile is embedded in the main support layer and the projectile's blast center is located in the main support layer, it is determined that the protective structure has been damaged. Specifically, when the calculation result of step (3) in step 102 is: V 03 >V BL3 If the projectile's head penetrates the main support layer and enters the interior of the protective structure, the protective structure will be destroyed and lose its protective capability.
[0044] Step 104: If the projectile is embedded in the shielding layer or the dispersion layer, calculate the first stress wave peak value at the top of the main support layer; use the virtual explosion source method to treat the projectile as if it exploded in the preset structure, and determine the position of the virtual explosion source in the preset structure based on the first stress wave peak value; determine whether the protective structure is damaged based on the position of the virtual explosion source in the preset structure and the thickness of the main support layer; wherein, the preset structure is formed of the same material as the main support layer.
[0045] Figure 4 This is a schematic diagram illustrating the calculation process for the critical collapse thickness according to an embodiment of the present invention. Figure 4 As shown, this paper introduces the calculation of the critical collapse thickness of a layered protective structure based on a virtual blast source, taking the example of the projectile penetrating and embedding into the shielding layer, with the explosive charge's detonation point also located within the shielding layer.
[0046] First, the calculation model for the propagation of explosion stress waves in the medium is as follows: Formula 3; Among them, P r The peak stress (MPa) is the stress exerted by the explosion on the bottom of the corresponding layer directly below the explosion center. The equivalent TNT weight of the projectile is expressed in kg. The distance, in meters, is the distance between the bottom of the corresponding layer into which the projectile is embedded, directly below the blast center; This is the coefficient for the depth of the explosive charge. The attenuation coefficient; This is the decay index.
[0047] When the projectile embeds into the shielding layer: ; When the projectile is embedded in the dispersion layer: ; When the projectile is embedded in the main support layer: ; Secondly, the calculation model for the peak stress transmitted through stress waves at the interface between two adjacent layers in the protective structure is as follows: Formula 4; in, The peak value of the stress wave transmitted to the top surface of the next layer, in MPa; The peak value of the stress wave on the bottom surface of the upper layer, in MPa; For the density of the medium in the next layer, ; The longitudinal wave velocity of the next layer, in m / s; The density of the medium in the upper layer, ; denoted as the longitudinal wave velocity of the medium in the upper layer, in m / s.
[0048] (1) Calculate the top stress of the main support layer according to Equations 3 and 4: When the projectile penetrates into the shielding layer and the explosion point is also located within the shielding layer, the stress peak value P1 at the bottom of the shielding layer can be calculated based on the stress wave propagation calculation model. ; Based on the stress wave propagation calculation model of the interface layer, the peak stress wave P at the top of the dispersion layer can be calculated. 20 ; ; According to Equation 3, calculate the peak stress wave P2 at the bottom of the dispersion layer: ; According to Equation 4, calculate the peak stress wave value (first peak stress wave value) P at the top of the supporting structure layer. 30 : ; (2) By using the virtual explosion source method, also known as the equivalent method, the final explosion position of the projectile is equivalent to the explosion in the embedded preset structure. The preset structure is formed using the same material as the main support layer.
[0049] Continue as Figure 4 As shown, the peak value P of the first stress wave generated by the virtual explosion source in the preset structure is calculated. 30 The location is determined, thus obtaining the distance R between the virtual explosion source and that location (let R = h at this point). x ).
[0050] Meanwhile, the critical collapse model for reinforced concrete considering different factors is as follows: Formula 5; in, Explosion parameters related to burial depth; These are the explosion parameters related to the aspect ratio; This is the equivalent of an exposed explosive charge. This refers to the length parameter of the projectile's head. is the elastic modulus of concrete, in MPa; is the axial compressive strength of concrete, in MPa; The density of concrete is expressed in kg / m³. 3 ; Let m be the structural parameter.
[0051] The first peak stress P is generated in the main support layer material (preset structure) based on the virtual explosion source method. 30 At that time, the thickness of the main support layer at which the explosive charge causes critical collapse, in meters; ; ; ; The mass of the projectile's propellant charge is expressed in kg. Let be the initial radius of the projectile shell, in meters. Let be the radius of expansion of the projectile shell, in meters; for ductile materials: steel shells can be approximated as... copper shell r p0 =2.24 r 0; This value should be smaller for brittle materials or pre-fragmented materials; Filling coefficient It is an index. ; The mass of the projectile casing is in kg. For exponents.
[0052] It should be noted that Equation 5 above considers the construction of a critical collapse model for reinforced concrete considering different factors. Supported by experimental and numerous numerical simulation results, and based on the traditional explosion formula for the critical collapse thickness of a reinforced concrete target under contact explosion, it considers the effects of burial depth, aspect ratio shell thickness and shell head length, and concrete target strength, thereby solving the problem of the difficulty in accurately determining the degree of damage.
[0053] (3) Based on the virtual explosion source and the peak value P of the first stress wave generated in the preset structure 30 The distance h between the positions x And the critical collapse thickness h when the virtual explosion source experiences critical collapse in the preset structure. r And taking into account the thickness H of the main support layer zt .
[0054] If h x +H zt <h r If this happens, the bottom of the supporting structure will collapse, destroying the layered protective structure and rendering it inoperable.
[0055] If h x +H zt h r This indicates that the layered protective structure was not destroyed under the combined effects of penetration and explosion.
[0056] The exemplary embodiment of this invention proposes a method for determining the damage of layered protective structures based on virtual blast sources. This method considers the nonlinear response of materials, the transmission and reflection effects of stress waves at the interlayer interfaces, and the coupling effect of multiple physical fields involved in the penetration process of a bunker-buster projectile into a layered protective structure. It also combines the virtual blast source method to calculate the critical collapse thickness of the corresponding medium material, thereby accurately assessing the damage effect of the protective structure.
[0057] Example 2 The present invention also provides a damage determination device for a layered protective structure based on a virtual explosion source, which is used in the damage determination method described in Embodiment 1.
[0058] A damage determination device for layered protective structures based on virtual explosion sources includes: The acquisition module is used to acquire the incident velocity of the projectile and the thickness of each layer of the protective structure. The protective structure, from the outside to the inside, includes a projectile shielding layer, a dispersion layer, and a main support layer. The determination module is used to determine the appropriate layer in the protective structure into which the projectile is embedded, based on the projectile's incident velocity and the thickness of the corresponding layer. The determination module is also used to determine if the protective structure is damaged if the projectile is embedded in the main support layer and the projectile's blast center is located in the main support layer; The determination module is also used to calculate the first stress wave peak value at the top of the main support layer if the projectile is embedded in the shielding layer or the dispersion layer; to use the virtual explosion source method to treat the projectile as if it explodes in the preset structure, and to determine the position of the virtual explosion source in the preset structure based on the first stress wave peak value; and to determine whether the protective structure is damaged based on the position of the virtual explosion source in the preset structure and the thickness of the main support layer; wherein the preset structure is formed of the same material as the main support layer.
[0059] The technical advantages of the aforementioned damage determination device compared to the prior art are the same as those of the aforementioned damage determination method, and will not be repeated here.
[0060] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.
Claims
1. A method for determining the damage of a layered protective structure based on a virtual explosion source, characterized in that, include: The incident velocity of the projectile and the thickness of each layer of the protective structure are obtained, wherein the protective structure includes, from the outside to the inside, a projectile shielding layer, a dispersion layer and a main support layer; Based on the incident velocity of the projectile and the thickness of the corresponding layer, it is determined that the projectile is embedded in the corresponding layer of the protective structure; If the projectile is embedded in the main support layer and the projectile's blast center is located in the main support layer, the protective structure is determined to be damaged. If the projectile is embedded in the shielding layer or the dispersion layer, calculate the first stress wave peak value at the top of the main support layer; use the virtual explosion source method to treat the projectile as if it exploded in a preset structure, and determine the position of the virtual explosion source in the preset structure based on the first stress wave peak value; determine whether the protective structure is damaged based on the position of the virtual explosion source in the preset structure and the thickness of the main support layer; wherein, the preset structure is formed of the same material as the main support layer.
2. The method for determining damage according to claim 1, characterized in that, Based on the first stress wave peak value, the location of the virtual explosion source in the preset structure is determined, including: In the preset structure, when the first stress wave peak is generated directly below the virtual explosion source, there is a first distance between the virtual explosion source and the location of the generated first stress wave peak.
3. The method for determining damage according to claim 2, characterized in that, When using the virtual explosion source method to equate the projectile to an explosion in a preset structure, the method further includes: When the virtual explosion source detonates in the preset structure, the critical collapse thickness at which the preset structure collapses is calculated.
4. The method for determining damage according to claim 3, characterized in that, Based on the first distance, the thickness of the main support layer, and the critical collapse thickness, it is determined whether the protective structure has been damaged.
5. The damage determination method according to claim 4, characterized in that, If the sum of the first distance and the thickness of the main support layer is less than the critical collapse thickness, the protective structure is determined to be damaged; otherwise, the protective structure is determined to be undamaged.
6. The method for determining damage according to claim 3, characterized in that, The critical collapse thickness h when the preset structure collapses is mentioned. r satisfy: ， in, Explosion parameters related to burial depth; These are the explosion parameters related to the aspect ratio; This is the equivalent of an exposed explosive charge. This refers to the length parameter of the projectile's head. is the elastic modulus of concrete, in MPa; is the axial compressive strength of concrete, in MPa; The density of concrete, kg / m³ 3 ; Let m be the structural parameter.
7. The method for determining damage according to any one of claims 1-6, characterized in that, Calculating the first stress wave peak value at the top of the main support layer includes: Based on the interface layer stress wave propagation model, the peak value of the first stress wave at the top of the main support layer is calculated.
8. The method for determining damage according to claim 7, characterized in that, The stress wave propagation model satisfies: ， Among them, P r The peak stress (MPa) is the stress exerted by the explosion on the bottom of the corresponding layer directly below the explosion center. The equivalent TNT weight of the projectile is expressed in kg. The distance, in meters, is the distance between the bottom of the corresponding layer into which the projectile is embedded, and the center of the explosion. This is the coefficient for the depth of the explosive charge. The attenuation coefficient; This is the decay index.
9. The method for determining damage according to claim 8, characterized in that, Based on the projectile's structural parameters, the location of the explosion center is calculated, satisfying the following: ， Among them, H qb H is the distance from the projectile's epicenter to the top surface of the shielding layer after the projectile has penetrated the protective structure, in meters; H is the penetration depth of the projectile in the protective structure, in meters; l is the projectile length, in meters; K b β is the deflection coefficient of the projectile in the material; β is the impact angle of the projectile.
10. A device for determining the damage of a layered protective structure based on a virtual explosion source, characterized in that, Used in the destruction determination method according to any one of claims 1-9.