A quick assessment method of damage effect of large fragment warhead

Abstract

The application discloses a kind of quick evaluation methods of large fragment warhead damage effect, it is related to evaluation method technical field, and its technical solution points are: including the following steps: S1: according to the static fragment ground power field of different warhead model characteristics, according to different striking target establishes target characteristic data, constructs database, provides basic data for subsequent quick damage analysis;S2: according to normal kinetic energy criterion, according to light, moderate, severe three grades of damage level, establishes single preformed fragment target damage judgment basis;S3: constructs the quick damage algorithm of fragment warhead to target;S4: based on the damage probability model of fragment to target different components, quickly gives the evaluation conclusion of warhead to target component and overall damage effect.In the application, by using the technical scheme, the evaluation time of traditional evaluation method can be improved to seconds, and the related problems in the prior art that are difficult to meet the requirements of both calculation accuracy and quick damage evaluation are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of evaluation method, more particularly, it relates to a kind of large fragment warhead damage effect fast evaluation method. BACKGROUND

[0002] Fragment warhead relies on explosion, forms or drives a large number of fragments to fly at high speed, and achieves the purpose of damage by colliding with the target.

[0003] Damage assessment is to analyze and predict the damage effect of warhead in advance, so as to support the use decision of warhead and improve the efficiency of attack.

[0004] For fragment warhead, there are mainly two methods for existing damage assessment:

[0005] (1) Experience analysis: rely on empirical formula to make simple calculation. This method is simple to calculate, but the calculation accuracy is low, and it is not applicable to complex damage scenarios;

[0006] (2) Numerical simulation: based on finite element / finite difference algorithm, numerical calculation is carried out. This method has high calculation accuracy and meets the needs of complex damage scenarios, but the calculation amount is large, even if high-performance computing platform is used, it is also difficult to meet the demand of rapid evaluation.

[0007] However, in the prior art, it is difficult to meet the requirements of ensuring calculation accuracy and realizing rapid damage assessment. In view of this, the present application provides a kind of large fragment warhead damage effect fast evaluation method to solve the above-mentioned related problems. SUMMARY

[0008] The purpose of the present application is to provide a kind of large fragment warhead damage effect fast evaluation method, which realizes both guaranteeing calculation accuracy and realizing rapid damage assessment.

[0009] The above technical purpose of the present application is realized by the following technical scheme: a kind of large fragment warhead damage effect fast evaluation method, comprising the following steps:

[0010] S1: according to different warhead model characteristics, construct static fragment ground power field, according to different attack targets, establish target characteristic data, construct database, provide basic data for subsequent rapid damage analysis;

[0011] S2: according to the normal kinetic energy criterion, according to the three levels of light, medium and heavy damage level, establish the damage judgment basis of single preformed fragment to target;

[0012] S3: construct the rapid damage algorithm of fragment warhead to target;

[0013] The specific steps of the rapid damage algorithm are as follows:

[0014] S3.1: Read the position and velocity information data of all preformed fragments of the fragment warhead from the warhead power field database, and perform coordinate transformation on the position and velocity information data of all preformed fragments according to the spatial position and velocity vector when the fragment warhead is detonated.

[0015] S3.2: Calculate the flight motion process of the fragments according to the following formula:

[0016]

[0017] Wherein, m is the mass of the fragment, v is the velocity of the fragment, t is the time, C x is the air resistance coefficient, p is the local air density, and S is the windward area of the fragment; generally, the flight velocity of the fragment is between 1-3Ma, at this time, for spherical tungsten bead fragments, C x = 0.97;

[0018] S3.3: Calculate the intersection parameters of the fragments and the target surface, the intersection parameters including the velocity of the fragment when hitting the target surface, the included angle θ between the velocity direction of the fragment and the normal of the target surface at the impact point, and the component number N k of the impact point of the target surface;

[0019] S4: Based on the damage probability model of the fragments to different components of the target, the evaluation conclusion of the damage effect of the warhead to the components and the whole target is quickly given;

[0020] Wherein, according to the intersection parameters of the projectile and the target, the number of fragments hitting the target and the angle of kinetic energy penetration of each fragment are obtained, and the number of fragments effectively penetrating the target is calculated.

[0021] The application is further provided as follows: in step S1, the static fragment ground power field is constructed, specifically:

[0022] The warhead shell and the warhead charge shell adopt the Lagrange method to construct the finite element model, the preformed fragments adopt the discrete element method to construct the finite element model, and the warhead charge adopts the Euler method to construct the finite element model;

[0023] The finite element software LS-DYNA is used to perform high-precision simulation calculation on the charge detonation and preformed fragment scattering process under the static explosion condition of the warhead, and the state parameters of all preformed fragments when the driving effect of the charge explosion on the preformed fragments ends are obtained, that is, the warhead power field, including the spatial three-dimensional coordinate values (x i ′, y i ′, z i ′) and the component values of the velocity mass in the three directions (v′ xi ,v′yi ,v z ′ i ), wherein i is the preformed fragment number; the warhead coordinate system is denoted as (o'x'y'z'), the origin o' is located at the geometric center of the warhead, the symmetry axis of the warhead coincides with the z' axis of the coordinate system, and the front end of the warhead faces the negative direction of the z' axis.

[0024] The application is further provided as follows: in step S1, the warhead model characteristics include warhead size, charge power, and preformed fragment type.

[0025] The application is further provided as follows: in step S1, the target characteristic data is constructed, in particular:

[0026] According to the specific target to be attacked, the target characteristic data is established, and the target characteristic data includes a three-dimensional geometric shape (in IGS format), a spatial position coordinate, and an orientation vector, and the target coordinate system is denoted as (oxyz); the origin o is located at the geometric center of the target, and the target orientation (such as the vehicle head direction) coincides with the positive direction of the x axis.

[0027] The application is further provided as follows: the target to be attacked includes personnel, vehicles, and aircraft.

[0028] The application is further provided as follows: in step S2, the judgment basis for the damage of a single preformed fragment to the target is established according to the specific steps as follows:

[0029] S2.1: high-speed impact tests of the fragments on the target are carried out to pre-divide the regions, and damage levels of the target regions under different typical impact velocities and impact angles are obtained.

[0030] S2.2: according to the test results, a finite element simulation calculation model identical to the test conditions is established, and model parameters are corrected; according to the corrected simulation model, high-flux simulation calculation is carried out on test conditions not covered by the test, and damage levels of the fragments on the target regions under various impact velocities and impact angles are obtained.

[0031] S2.3: according to the normal kinetic energy criterion, the damage judgment basis corresponding to different normal impact velocities of the fragments on the target regions is established by comprehensively considering the test and simulation results.

[0032] The application is further provided as follows: in step S3.1, the coordinate transformation is specifically as follows:

[0033] S3.1.1: the terminal velocity of the warhead at the time of detonation is decomposed along the coordinate axes in the target coordinate system (oxyz), that is, decomposed into: v 0x ,v 0y ,v 0z ; the velocity components v' of each fragment are read from the warhead power field databasexi yi z i xi yi zi

[0034]

[0035] 0x 0y 0z xi yi zi

[0036] 0i 0i 0i i i i i i i

[0037]

[0038] i i i 0i 0i 0i i i i ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0039] The warhead is an axisymmetric geometry before being initiated, the whole space posture is described by a rectangular coordinate system (o'x'y'z') with z' as the axis, and the relation of the motion trajectory of the warhead relative to the ground is described by an absolute coordinate system (oxyz), thus, a rectangular coordinate system (oxyz) fixed on the ground is established with the target position as the coordinate origin, and the z axis is perpendicular to the ground upward; and a rectangular coordinate system (o'x'y'z') of the warhead is established with the mass center position of the warhead as the origin, the z' axis is coincident with the axis of the warhead and points to the rear of the warhead;

[0040] S3.1.3: the cylindrical coordinate system of the warhead is converted into a rectangular coordinate system, which is performed by the following way:

[0041] The cylindrical coordinate of the warhead The conversion into the rectangular coordinate system (o'x'y'z') is calculated by the following formula:

[0042]

[0043] Wherein, p is the radius of the cylindrical surface circle where the arbitrary fragment M is located, and θ is the included angle between OM and the x axis. The formula can convert the position coordinate of the arbitrary fragment M from the cylindrical coordinate system of the warhead into the rectangular coordinate system (o'x'y'z'). The conversion into the rectangular coordinate system (o'x'y'z') of the warhead;

[0044] The conversion formula of the rectangular coordinate of the warhead into the rectangular coordinate system of the target is:

[0045]

[0046] Wherein, x, y and z are the coordinate parameters of the rectangular coordinate system of the target; α is the included angle between the connecting line between the warhead and the target and the x axis of the target coordinate system; and H is the vertical distance between the warhead and the ground when the warhead is exploded, i.e. the burst height.

[0047] Through the above conversion mode, the distribution of the fragment power field at any moment in the dynamic flight process can be quickly obtained in combination with the fragment flight equation.

[0048] The application is further provided as follows: in step S4, the damage probability model is specifically:

[0049] According to the intersection parameters of each fragment and the target surface, the damage level of a single component area is calculated;

[0050] Wherein, when each fragment can make the assumption that the damage effect of each fragment on the target is an independent event in the process of flying, the probability superposition problem between the fragments satisfies the independent random event operation rule; assuming that n fragments hit the same component and cause different damage probabilities, respectively: (p1A ,p 1B ,p 1C ), (p 2A ,p 2B ,p 2C ) … (p nA ,p nB ,p nC ), wherein A, B and C represent heavy, moderate, mild damage respectively; for the case that n fragments hit the same component, the probability of causing different levels of damage to the component is calculated by using the two-by-two superposition method;

[0051] The damage between target components is also regarded as independent probability events, so the damage probability of the whole target is also calculated by using the two-by-two superposition method.

[0052] In summary, the present application has the following beneficial effects:

[0053] 1. The discrete element method, Euler method and Lagrange method are used to construct a numerical simulation model, the simulated fragment quantity is large, the system is large, the calculation precision is high, and the model is established by combining experiments and simulation, so that the simulation result and evaluation conclusion are more real and reliable;

[0054] 2. The high-performance computer is used to pre-calculate and construct a static power field database, which can be applied to various types of fragment warheads, the coordinate transformation calculation method can be used for different strike conditions, meets the needs of complex damage scenes, and can improve the evaluation time of the traditional evaluation method from hours to seconds, that is, the calculation precision is ensured, and fast damage evaluation is realized. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is a large fragment warhead rapid evaluation method model in the embodiment of the present application;

[0056] Figure 2 is a fragment warhead model constructed in the embodiment of the present application;

[0057] Figure 3 is a warhead coordinate system schematic diagram in the embodiment of the present application;

[0058] Figure 4 is a target characteristic data schematic diagram in the embodiment of the present application;

[0059] Figure 5 is a damage probability criterion established according to the target in the embodiment of the present application;

[0060] Figure 6 is a warhead coordinate system and target coordinate system schematic diagram in the embodiment of the present application;

[0061] Figure 7This is a schematic diagram of the cylindrical coordinate system and the rectangular coordinate system of the warhead in an embodiment of the present invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] The following is in conjunction with the appendix Figures 1-3 The present invention will be described in further detail below.

[0064] Example: A rapid assessment method for the damage effect of a large fragmentation warhead, such as... Figure 1 As shown, it includes the following steps:

[0065] S1: Construct a static fragmentation ground force field based on the characteristics of different warhead models, establish target characteristic data based on different targets, and build a database to provide basic data for subsequent rapid damage analysis;

[0066] A finite element model of a large fragmentation warhead was established based on the discrete element method, Eulerian method, and Lagrange method. The geometric model is as follows: Figure 2 As shown, 1 represents the warhead casing, 2 represents the pre-fragmented components, 3 represents the warhead charge casing, 4 represents the warhead charge, and 5 represents the detonation point. The warhead casing 1 and the warhead charge casing 2 are modeled using the Lagrange method (finite element method), the pre-fragmented components 2 are modeled using the discrete element method (Discrete Element Method), and the warhead charge 4 is modeled using the Euler method (Eulerian Method). The total mass of the warhead can reach the ton level, and the number of pre-fragmented components inside can reach over one hundred thousand.

[0067] When the warhead is activated, the warhead charge 4 detonates from the detonation point 5. After the detonation, high-temperature and high-pressure gaseous products are generated, which drive the warhead charge casing 2 to expand outward, push the pre-fragmented fragments 2 outward, and cause the warhead casing 1 to break rapidly. A large number of pre-fragmented fragments continue to accelerate outward under the action of the explosion products. After a period of time, the temperature and pressure of the explosion products drop due to rapid expansion, and they can no longer do work on the pre-fragmented fragments. The pre-fragmented fragments continue to move under the action of inertia, air resistance and gravity until they hit the target and strike it.

[0068] Because of the large volume of warhead, the internal filling precast quantity is much, using finite element method to simulate the process of its charge explosion and precast fragment dispersion needs to spend a lot of time. The present application adopts finite element software LS-DYNA to carry out high-precision simulation calculation on the process of charge explosion and precast fragment dispersion under the condition of static explosion of warhead, obtains the state parameters of all precast fragments when the driving effect of charge explosion on precast fragments ends, i.e. the warhead power field, including the spatial three-dimensional coordinate values (x i ′,y i ′,z i ′,i=1,2,3……, which represent the precast fragment number) and the component values of velocity mass in three directions (v′ xi ,v′ yi ,v z ′ i ,i=1,2,3……, which represent the precast fragment number) in the spatial three-dimensional coordinate system; the warhead coordinate system is denoted as (o′x′y′z′), as Figure 3 , the origin o′ is located at the geometric center of the warhead, the symmetry axis of the warhead coincides with the z′ axis of the coordinate system, and the front end of the warhead faces the negative direction of the z′ axis.

[0069] According to the specific target to be hit, such as vehicle, personnel, aircraft, etc., the target characteristic data is established, including three-dimensional geometric shape (IGS format), spatial position coordinates and orientation vector, such as Figure 4 . The target coordinate system is denoted as (oxyz); the origin o is located at the geometric center of the target, and the target orientation (such as the vehicle head direction) coincides with the positive direction of the x axis.

[0070] The warhead power field and the target characteristic data constitute a database, which provides basic data for subsequent rapid damage analysis.

[0071] S2: According to the normal kinetic energy criterion, the damage judgment basis of a single precast fragment to the target is established according to the light, medium and heavy three damage levels;

[0072] According to the kinetic energy criterion, the damage judgment basis of a single precast fragment to the target is established. Generally, the damage effects caused by the fragments hitting different positions on the target surface are different, therefore, the target needs to be divided into a certain number of component regions N k (k=1,2,3…), and the damage judgment basis is established according to the light, medium and heavy three damage levels, respectively.

[0073] Firstly, high-speed impact tests of fragments on the pre-divided regions of the target are carried out, and the damage levels of the target regions under different typical impact velocities and impact angles are obtained.

[0074] Secondly, based on the test results, a finite element simulation calculation model identical to the test conditions was established, and the model parameters were corrected. Based on the corrected simulation model, high-throughput simulation calculations were carried out for test conditions not covered by the test to obtain detailed information on the damage level of fragments to the target area under various impact velocities and impact angles.

[0075] Finally, based on the combined experimental and simulation results and in accordance with the normal kinetic energy criterion, a damage assessment basis was established for different normal impact velocities of fragments on the target area.

[0076] The established criteria for damage assessment are as follows: Figure 5 As shown. p represents the damage probability, with a value range of [0,1]; v1, v2, and v3 represent the normal velocities of the fragments to the target area under three different working conditions.

[0077] S3: Construct a rapid damage algorithm for fragmentation warheads on targets;

[0078] The rapid destruction algorithm of a fragmentation warhead against a target consists of the following steps:

[0079] (1) Read the position and velocity information data of all pre-fragmented fragments of the fragmentation warhead from the warhead power field database, and perform coordinate transformation on the position and velocity information data of all pre-fragmented fragments based on the spatial position and velocity vector of the fragmentation warhead at the time of detonation.

[0080] First, the terminal velocity of the warhead at detonation is decomposed along the coordinate axes in the target coordinate system (oxyz), that is, decomposed into: v 0x ,v 0y ,v 0z The velocity component v′ of each fragment is read from the warhead power field database. xi ,v′ yi ,v z ′ i (i = 1, 2, 3..., representing the pre-fragment numbers), transform the fragment velocity components from the warhead coordinate system to the target coordinate system, and the velocity component v of the fragment in the target coordinate system (oxyz). xi ,v yi ,v zi They are represented as follows:

[0081]

[0082] Secondly, coordinate transformation is performed on the spatial positions of all fragments. Based on the established projectile-target intersection conditions, the position component x of the warhead's geometric center in the target coordinate system (oxyz) is determined. 0i ,y 0i ,z 0i Given known quantities. The positional component (x) of each fragment is read from the warhead power field database. i', y i ', z i ', i = 1, 2, 3,..., represents the number of prefabricated fragments), the fragment position component is converted from the warhead coordinate system to the target coordinate system, and the position component x i , y i , z i respectively as:

[0083]

[0084] The warhead is an axisymmetric geometric body before detonation, and the overall spatial posture is described by the rectangular coordinate system (o'x'y'z') with z' as the axis. The relationship of the motion trajectory relative to the ground is described by the absolute coordinate system (oxyz). Therefore, a rectangular coordinate system (oxyz) fixed on the ground is established with the target position as the coordinate origin, and the z axis is perpendicular to the ground upward. Then, a warhead rectangular coordinate system (o'x'y'z') is established with the centroid position of the warhead as the origin, and z' coincides with the warhead axis and points to the rear of the warhead.

[0085] The relative relationship between the two coordinate systems can make oxz and o'x'z' in the same plane of projection, and y and y' axes are two parallel lines perpendicular to the plane of projection, as shown in Figure 5 .

[0086] Figure 6 In the formula, the vertical projection point of the warhead on the ground is o", the vertical distance between the warhead and the ground is the burst height H = o'o", and o is the target point.

[0087] As shown in Figure 7 , the warhead cylindrical coordinates (p, f, z) are converted into the rectangular coordinate system (o'x'y'z'), and the calculation formula is:

[0088]

[0089] The warhead rectangular coordinate conversion to the target rectangular coordinate system conversion formula is:

[0090]

[0091] Through the above transformation mode, combined with the fragment flight equation, the distribution of the fragment power field at any time during the dynamic flight process can be quickly obtained.

[0092] (2) The flight motion process of the fragment is calculated according to the following formula:

[0093]

[0094] m is the mass of the fragment, v is the speed of the fragment, t is the time, C xwhere C D is the air resistance coefficient, p is the local air density, and S is the area of the fragment facing the wind. Generally, the fragment velocity is between 1 and 3 Ma.

[0095] (3) Calculate the intersection parameters of the fragment and the target surface, including the speed of the fragment when it hits the target surface (f represents that the fragment hits the target surface, i is the fragment number), the angle θ between the direction of the fragment velocity and the normal of the impact point on the target surface, and the component number N to which the impact point on the target surface belongs k .

[0096] S4: Based on the damage probability model of the fragments to different components of the target, quickly give the evaluation conclusion of the damage effect of the warhead on the target components and the whole;

[0097] (1) According to the intersection parameters of each fragment and the target surface, calculate the damage level of the single component area. Since the fragments do not affect each other during the dispersion process, the dispersion trajectories of the fragments do not coincide, so the probability of hitting the same position of the target is almost zero. When each fragment is in the process of dispersion, it can be assumed that the damage effect of each fragment on the target is an independent event. Therefore, the probability superposition problem between fragments satisfies the operation rule of independent random events. Assuming that n fragments hit the same component and cause different levels of damage probabilities are: (p 1A ,p 1B ,p 1C ), (p 2A ,p 2B ,p 2C )···(p nA ,p nB ,p nC ), A, B and C represent severe, moderate and mild damage respectively.

[0098] The superimposed damage effect of each case can be roughly divided into two types:

[0099] First, the superposition of two same type damage effects, for example, AA superposition. Since the effects of fragments are independent of each other, it can be judged that the damage level is still A level.

[0100] The other case is the superposition of two different levels of damage effects, for example, AB superposition. Since one fragment has reached the A level damage effect, the target has reached the highest level of damage, so other fragments will not change the final judgment result no matter what damage effect they cause.

[0101] Taking 2 fragments hitting the same component as an example, the superimposed damage probability is:

[0102] p 12A =p 1A p2A +p 1A p 2B +p 1A p 2C +p 1B p 2A +p 1C p 2A

[0103] p 12B =p 1B p 2B +p 1B p 2C +p 1C p 2B

[0104] p 12C =p 1C p 2C

[0105] For further simplification of the calculation and facilitate understanding, for n fragments hit the component, eventually resulting in the formation of different levels of damage probability components can be used to add two two calculation method:

[0106]

[0107] This is the probability of damage of a single component N k by fragments, (p 1,2…nA , p 1,2…nB , p 1,2…nC ) is denoted as p k , the damage between the components of the target can also be regarded as independent probability events, so the damage probability of the whole target is calculated by superposition, using the same calculation method as the multiple fragments hitting the same component.

[0108] (2) According to the parameters of the missile-target encounter, the number of fragments hitting the target and the angle of kinetic energy penetration of each fragment can be obtained, thereby giving the number of effective fragments penetrating the target.

[0109] Based on the ray detection method, the ray refers to an infinite line extending from the coordinate point of a single fragment after detonation in three-dimensional space along the velocity direction. On the trajectory of the ray, once a collision occurs with the added target model, the emission will stop, and the collision point information will be returned. The collision point information includes the collision target type, collision velocity and collision point coordinates.

[0110] The specific embodiments are merely an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for quick assessment of damage effect of large fragment warhead, characterized in that, The method comprises the following steps: S1: constructing a static fragment ground power field according to different warhead model characteristics, establishing target characteristic data according to different attack targets, constructing a database, and providing basic data for subsequent rapid damage analysis; S2: establishing a single preformed fragment target damage judgment basis according to the normal kinetic energy criterion and in accordance with light, medium and heavy damage levels; S3: constructing a rapid damage algorithm of the fragment warhead to the target; The rapid damage algorithm comprises the following steps: S3.1: reading position and speed information data of all preformed fragments of the fragment warhead from the warhead power field database, and performing coordinate transformation on the position and speed information data of all preformed fragments according to the spatial position and speed vector when the fragment warhead is detonated; S3.2: calculating the flight motion process of the fragments according to the following formula: ； where m is the mass of the fragment, v is the velocity of the fragment, t is time, C x is the air drag coefficient, p is the local air density, and S is the cross-sectional area of the fragment normal to the direction of flight; the velocity of the fragment is between 1 and 3 Ma, at which time for a spherical tungsten fragment, C x = 0.

97. S3.3: Calculate the intersection parameters of the fragment and the target surface, which include the speed size of the fragment when it hits the target surface, the included angle θ between the speed direction of the fragment and the normal of the target surface at the hitting point, and the component number N to which the hitting point belongs k ; S4: rapidly giving an evaluation conclusion of the damage effect of the warhead to the target components and the whole target based on the damage probability model of the fragments to different components of the target; Wherein, the number of fragments hitting the target and the angle of each fragment kinetic penetration are obtained according to the bullet-target intersection parameters, and the number of fragments effectively penetrating the target is calculated; In step S3.1, the coordinate transformation comprises the following steps: S3.1.1: The terminal velocity of the warhead when it is detonated is decomposed along the coordinate axes in the target coordinate system (oxyz), i.e. into , , ; the velocity components of each fragment are read from the warhead power field database , , ; the velocity components of the fragments are converted from the warhead coordinate system to the target coordinate system, the velocity components of the fragments in the target coordinate system (oxyz) being , , respectively. ； wherein, , , is the decomposed velocity of the last speed along the coordinate axis in the target coordinate system (oxyz); , , is the velocity component of the fragment in the target coordinate system (oxyz), i=1,2,3…, indicating the number of prefabricated fragments; S3.1.2: Coordinate transformation is performed on the spatial position of all fragments; the warhead does not rotate in the static explosion power field, and according to the set missile-target intersection condition, the position component of the warhead geometric center in the target coordinate system (oxyz) , , is a known quantity; the position component of each fragment is read from the warhead power field database ( , , ), and the position component of the fragment is converted from the warhead coordinate system to the target coordinate system, at which time the position component of the fragment in the target coordinate system (oxyz) , , is respectively represented as: ； wherein, , and are the position components of the fragments in the target coordinate system (oxyz), i = 1, 2, 3,..., indicating the number of preformed fragments; , and are the position components of the geometric center of the warhead in the target coordinate system (oxyz); , and are the position components of the fragments in the warhead power field database; The warhead before detonation is an axisymmetric geometric body, the overall spatial posture is described by a rectangular coordinate system (o´x´y´z´) with z´ as the axis, and the motion trajectory relative to the ground is described by an absolute coordinate system (oxyz), therefore, a rectangular coordinate system (oxyz) fixed on the ground is established with the target position as the coordinate origin, and the z axis is perpendicular to the ground and upward; and a rectangular coordinate system (o´x´y´z´) of the warhead is established with the centroid position of the warhead as the origin, the z´ coincides with the axis of the warhead and points to the rear of the warhead; S3.1.3: converting the cylindrical coordinate system of the warhead into the rectangular coordinate system by the following way: The warhead cylindrical coordinate (ρ, φ, z) is converted into the rectangular coordinate system (o´x´y´z´), and the calculation formula is: ； Wherein, ρ is the radius of the cylindrical surface circle where any fragment M is located, φ is the included angle between OM and the x axis, x´, y´ and z´ are the rectangular coordinate system coordinate parameters, and the formula can convert the position coordinates of any fragment M from the warhead cylindrical coordinate system (ρ, φ, z) to the warhead rectangular coordinate system (x´y´z´); The conversion formula of the warhead rectangular coordinate to the target rectangular coordinate system is: ； Wherein, x, y and z are the target rectangular coordinate system coordinate parameters; α is the included angle between the connecting line between the warhead and the target and the x axis of the target coordinate system; and H is the vertical distance between the warhead and the ground when the warhead explodes, i.e. the burst height; Through the above conversion way, the distribution of the fragment power field at any moment in the dynamic flight process is rapidly obtained in combination with the fragment flight equation.

2. The method for quick assessment of damage effect of large fragment warhead according to claim 1, wherein, In step S1, the static fragment ground power field is constructed, and specifically: The finite element model of the warhead shell and the warhead charge shell is constructed by using the Lagrange method, the finite element model of the preformed fragments is constructed by using the discrete element method, and the finite element model of the warhead charge is constructed by using the Euler method. The high-precision simulation calculation is performed on the charge explosion and the flying process of the preformed fragments under the static explosion condition of the warhead by using the finite element software LS-DYNA, and the state parameters of all the preformed fragments at the end of the driving action of the charge explosion, i.e., the warhead power field, are obtained, including the spatial three-dimensional coordinate values ( , , ) of each preformed fragment and the component values ( , , ) of the speed mass in three directions in the spatial three-dimensional coordinate system, wherein i is the preformed fragment number; the warhead coordinate system is denoted as (o´x´y´z´), the origin o´ is located at the geometric center of the warhead, the symmetry axis of the warhead coincides with the z´ axis of the coordinate system, and the front end of the warhead faces the negative direction of the z´ axis.

3. The method of claim 1, wherein, In step S1, the warhead model characteristics comprise warhead size, charge power and preformed fragment type.

4. The method of claim 1, wherein, In step S1, the target characteristic data is constructed, and specifically: According to the specific target to be hit, target characteristic data is established, which includes three-dimensional geometric shape, spatial position coordinates and orientation vector, and a target coordinate system is denoted as (oxyz), with the origin o located at the geometric center of the target and the target orientation coinciding with the positive direction of the x-axis.

5. The method for quick assessment of damage effect of large fragment warhead according to claim 4, characterized in that, The target to be hit includes personnel, vehicles and aircraft.

6. The method of claim 1, wherein, In step S2, the specific steps for establishing the single preformed fragment damage judgment basis for the target are as follows: S2.1: High-speed impact tests of fragments on the target are carried out to pre-divide the target area, and the damage levels of the target area under different typical impact velocities and impact angles are obtained; S2.2: According to the test results, a finite element simulation calculation model with the same test conditions is established, and the model parameters are corrected; according to the corrected simulation model, large-flux simulation calculation is carried out for test conditions not covered by the test, and the damage levels of the target area under various impact velocities and impact angles are obtained; S2.3: The test and simulation results are integrated, and the damage judgment basis corresponding to different normal impact velocities of fragments on the target area is established according to the normal kinetic energy criterion.

7. The method of claim 1, wherein, In step S4, the damage probability model is specifically: According to the intersection parameters of each fragment and the target surface, the damage level of a single component area is calculated; Wherein, when each fragment can make each fragment damage effect on the target during the process of flying is an independent event, the probability superposition problem between fragments meets the independent random event operation law; assuming that n fragments hit the same component, causing different levels of damage probability are: (p 1A , p 1B , p 1C ), (p 2A , p 2B , p 2C )···(p nA ,p nB , p nC ), wherein, A, B and C represent severe, moderate, mild damage; for n fragments hit the same component, the probability of causing different levels of damage to the component adopts the calculation method of two-by-two superposition; The damage between each component of the target is also considered as a mutually independent probability event, and the superposition calculation of the damage probability of the whole target also adopts the calculation method of two-by-two superposition.

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