CN108052702B - Lightning partitioning method based on lightning shortest path space geometric topology principle - Google Patents
Lightning partitioning method based on lightning shortest path space geometric topology principle Download PDFInfo
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Abstract
The invention discloses a lightning partitioning method based on the spatial geometric topological principle of the shortest path of lightning, which comprises the following steps: s1, dividing the target CAD model into grid models; s2, reading the target grid model file and constructing a data matrix of the network node; s3, establishing a central point coordinate data matrix of a target surface grid node tangent lightning stroke sphere, constructing the lightning stroke sphere and calculating the topological characteristic of a lightning stroke attachment point; s4, judging and calculating the lightning stroke probability characteristic of the lightning stroke contact point on the surface of the airplane target according to the result of the step S3; and S5, repeatedly executing the steps S3-S4 to calculate and count the lightning stroke probability of the same lightning stroke contact point under all the lightning stroke sphere radiuses, and obtaining the lightning stroke attachment point distribution result of the airplane target. The advantages are that: the method can effectively provide reference basis for lightning protection design and verification test and airworthiness conformance test of the aviation aircraft.
Description
Technical Field
The invention relates to the technical field of electromagnetic environment effects of aircrafts, in particular to a lightning partitioning method based on the spatial geometrical topological principle of a lightning shortest path.
Background
Lightning is one of the most common natural phenomena, and for various aircrafts, along with the adoption of a large amount of electronic equipment and novel composite materials, the lightning can affect the operation safety of the aircrafts and even possibly cause catastrophic accidents. Taking an aviation aircraft as an example, when the aircraft is struck by lightning, the top of a nose cone and a vertical tail of the aircraft body often become an inlet and an outlet for thunder, at the moment, the aircraft body structure becomes a thunder and lightning transmission channel, transient large current flows along the aircraft body structure, transient electromagnetic fields appearing outside and inside the aircraft body are coupled through an interconnection harness of equipment inside the aircraft body, transient high voltage and large current appear at an electronic and electrical equipment interface, the performance of airborne electronic and electrical equipment is disordered or reduced, and the aircraft is damaged and casualties are caused if the performance is low. Therefore, a lightning protection design is necessary when designing an aircraft.
The lightning partition is the first step of lightning protection design, and can provide important basis for lightning protection design and risk assessment of the aircraft. The lightning partition aims to determine the possible positions of attachment points of lightning channels and the areas through which lightning current flows between lightning outlet points and lightning inlet points, and determine different areas of the aircraft to adopt corresponding levels of lightning protection design and measures so as to reduce the influence of lightning phenomena on the aircraft.
At present, the main methods for lightning zoning comprise a similar analogy method, a test method and a simulation method. The similarity comparison method refers to the lightning zoning experience of the aircraft with similar structures, the lightning zoning experience passes the certification and the identification of an authority department or an airworthiness organization, and the lightning zoning is carried out on the newly designed or derived modified aircraft by adopting a similar analysis method. However, this method requires that each part of the aircraft is similar to previously validated aircraft and lightning zoning cannot be performed using a similar method if there is a large change between the aircraft requiring zoning and the aircraft that has been identified or there is a change in the electrical conductivity of the fuselage surface. The currently accepted lightning partition test is an airplane lightning attachment point test, the test is mainly carried out according to the standards of GJB 3567 'identification test method for military airplane lightning protection', navigation standard HB6129 'requirement and test method for airplane lightning protection', SAE ARP5414 'airplane lightning partition', SAE ARP5416 'airplane lightning effect test method', and the like, the high-voltage discharge test is carried out on a full-size or scaling model of an airplane in a laboratory, and the attachment area is recorded. A similar method is also mentioned in an academic paper 'airplane model lightning strike attachment point test research' published by Wenhao et al in 2006, and a lightning strike attachment point test is carried out on a scaled model of an airplane by adopting an impulse voltage generator. Although the airplane lightning attachment point test is a lightning partition method which is widely adopted at present, the test cost is high, the test period is long, and the test personnel have high-voltage electric shock risks, so that the airplane lightning attachment point test has many limitations. With the rapid development of computer technology, the lightning zoning simulation method is gradually applied to the design work of lightning effect protection of the aircraft.
Intellectual property rights and published documents published in lightning partition simulation at home and abroad are retrieved, and the lightning partition method based on the lightning shortest path spatial geometric topological principle, which is disclosed by the invention, is not retrieved, and the specific retrieval result is as follows:
1) invention patent retrieval scenario
(1) The Zhao Xiaoying et al, Beijing university of aerospace, obtained an authorization to invent patent "a method of generating an initial lightning strike attachment point for an aircraft" (patent application No. CN201310159421.4) at 2016.2.17. The invention discloses a method for generating an initial lightning strike attachment point of an aircraft, and belongs to the technical field of simulation of lightning direct effect of the aircraft. The method comprises the steps of firstly selecting a simulation area, calculating the probability of the development of each discharge channel to each possible breakdown point, calculating the potential of the discharge point which is possible to develop after determining one of the possible breakdown points as the next breakdown point according to the probability by a wheel disc rotation method, adjusting the boundary condition of the simulation area according to the potential, and repeatedly calculating until the condition that the lightning channel hits an aircraft or a downlink pilot develops until the space boundary is solved. And recording the times of lightning hitting a certain part of the aircraft in each discharging process to obtain the lightning stroke probability of the part. The method adopts a simulation method based on an electric field, and does not relate to the simulation method based on the space geometric topological principle.
(2) The Beijing aerospace engineering institute and the national Carrier rocket technical research institute, Zhongxian, Guo Hua dong, etc. are authorized at 2017.3.8 to invent a method for determining the lightning partition of a special vehicle (patent application No. CN 201610840046.3). The invention provides a special vehicle lightning partition simulation determination method, which is characterized in that different lightning discharge models are respectively arranged by simulating two different lightning strike forms, namely induced lightning strike which is easy to appear in the running process of a special vehicle and natural lightning strike which is easy to appear when the vehicle is parked, and the lightning partition conditions of the surface of the special vehicle under different lightning strike conditions are determined. The invention does not belong to the field of lightning simulation of aircrafts, and does not relate to the simulation method based on the space geometric topological principle.
(3) The invention discloses a device for counting the inlet and outlet points and measuring the current of an airplane lightning partition scaling model test (patent application number CN201120264575.6), which is issued by 2012.3.21 to Sheneng, Hausanhuang and the like of West electric and electric Provisions Limited of China. The invention relates to a device for counting the inlet and outlet points and measuring the current of an airplane lightning partition scaling model test related to a lightning partition test, and does not relate to a simulation method based on a space geometric topological principle.
2) Document retrieval scenario
(1) An academic paper entitled research on airplane thunder initial attachment simulation method is published in 2016 in the journal of aviation computing technology by people in the laboratory of Xian Aibang thunder and electromagnetic environment, namely a section goose super, and the lightning attachment point simulation method related in the text simulates the potential distribution of an airplane in a thunder environment simulated by a flat plate electrode and a rod electrode and judges whether the tip part of the surface of the airplane can become an in-point or an out-point of thunder according to the potential distribution of the surface of the airplane;
(2) an academic paper of electrostatic field numerical simulation analysis of aircraft lightning initial attachment area was published in 2014 by Fangjinpeng et al in an important laboratory of electromagnetic environment effect of aerospace craft in Shanghai city, wherein Finite Element (FEM) method is adopted for electrostatic field numerical calculation, a metal fuselage structure is regarded as an equipotential body, and the area of the maximum electric field intensity of the surface of an aircraft model is obtained and is the aircraft lightning initial attachment area;
(3) an academic paper of aircraft lightning strike attachment point value simulation research is published in 2012 by Zhao Yulong, university of second cannon war project, and the like, and the article relates to a simulation method of electrostatic field analysis, wherein an EM working room of CST electromagnetic simulation software is utilized to simulate a certain aircraft lightning strike attachment point on an equal-proportion model;
(4) the academic paper of Study of numerical simulation of air lighting and tuning based on CST software was published in 2011 by Shuang Song et al of national emphasis laboratories for electromagnetic environmental effects, and the article also relates to an electrostatic field-based Lightning strike attachment point simulation method using an EM studio of CST electromagnetic simulation software.
Disclosure of Invention
The invention aims to provide a lightning partitioning method based on a lightning shortest path space geometric topological principle, which adopts the principle based on the lightning shortest path, utilizes a space geometric algorithm of the interaction between lightning and an airplane, calculates lightning stroke attachment points by rolling a ball body on the surface of the airplane, the point contacted by the ball body corresponds to a lightning stroke entry point, and the probability that the basic surface of the airplane is possibly hit by the lightning can be deduced on the outer surface generated in the center of the ball body, so that the calculation and analysis of the lightning stroke attachment area are carried out, the method is suitable for all-aircraft lightning partitioning of various aviation aircrafts, the calculation is simple, convenient and rapid, the accuracy is high, and reference basis can be effectively provided for lightning protection design and verification tests and airworthiness conformance tests of the aviation aircrafts.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a lightning partitioning method based on the lightning shortest path space geometric topological principle is characterized by comprising the following steps:
s1, dividing the target CAD model into grid models;
s2, reading the target grid model file and constructing a data matrix of the network node;
s3, establishing a central point coordinate data matrix of a target surface grid node tangent lightning stroke sphere, constructing the lightning stroke sphere and calculating the topological characteristic of a lightning stroke attachment point;
s4, judging and calculating the lightning stroke probability characteristic of the lightning stroke contact point on the surface of the airplane target according to the result of the step S3;
and S5, repeatedly executing the steps S3-S4 to calculate and count the lightning stroke probability of the same lightning stroke contact point under all the lightning stroke sphere radiuses, and obtaining the lightning stroke attachment point distribution result of the airplane target.
The lightning partitioning method based on the lightning shortest path spatial geometric topological principle includes, in step S3:
s31, using the target grid node VmAs a calculation starting point, establishing a lightning stroke sphere with R as a radius, wherein the selected formula of the radius R is as follows:
R＝a×Ib (1)
wherein a is a coefficient in the range of 1-20, b is a coefficient in the range of 0.2-1, the coefficient values depending on the model of the down lightning negative leader; i is lightning peak current;
s32 meterCalculating the node V from the center of the lightning stroke sphere to the target surfacekDistance R ofk-m-0：
In the formula, a target surface node VkThe coordinate is Ak(xk,yk,zk)；VmHas the coordinate of Am(xm,ym,zm) (ii) a And node VmTangential lightning stroke sphere BmThe coordinate of the central point of the grid model is Bm-0(xm-0,ym-o,zm-0)；
S33, calculating the nodes in the whole target grid model according to the step S32 to obtain a group of lightning stroke spheres BmJudging the shortest distance from the center of the lightning stroke sphere to the surface of the target by using a distance data matrix from the center to the surface of the target;
when k is m, Rk-m-0When data in the distance data matrix is smaller than R, the lightning stroke sphere is overlapped with other parts of the target at the node of the target, the node position is not attached by lightning stroke, and the central position of the lightning stroke sphere corresponding to the node is assigned to be 0; when the minimum data in the distance data matrix is r, and the point of tangency between the center of the lightning stroke sphere and the target surface is at a node VmThe tangential direction of the combined surface element at the six-surface angle indicates that the group of data is effective, the coordinate of the central point of the lightning stroke sphere at the moment is recorded, and the position is assigned as 1;
s34, repeating the steps S32 and S33, sequentially calculating the shortest distance from the center of a tangent sphere at each node in the target network model to the surface of the target, judging whether the sphere at the position is overlapped with other positions of the target or not, recording the coordinate of the center point of the lightning stroke sphere at the moment when the effective data condition in the step S33 is achieved, and establishing a lightning stroke external envelope network, namely a coordinate data matrix of the center point of the target grid node tangent lightning stroke sphere;
s35, obtaining a topological data structure of the lightning strike attachment point, namely lightning external triangular grid data:
Bm-0＝Am+R×Nm (3)
in the formula: n is a radical ofmIs a target grid node VmNormalized normal vector coordinates of (a).
The lightning partitioning method based on the lightning shortest path spatial geometric topological principle includes, in step S4:
s41, searching and judging the number of the connected local triangular meshes at the lightning stroke position of the airplane model; the number is used for determining an external triangular mesh of all shared sphere center nodes of the current lightning strike contact point;
s42, calculating the external triangular mesh surface area of the target lightning strike contact point:
when node VmWhen the value of the coordinate matrix of the central point of the tangent lightning stroke sphere is 0, the node VmThe lightning stroke probability of the corresponding hexagonal combined surface element is 0; when the value of the coordinate matrix of the central point of the lightning stroke sphere is 1, the current lightning stroke contact point is obtained;
computing node VmS of the outer triangular mesh model correlationi、St-m、StarThe surface area, calculated as:
in the formula, ai、bi、ci3 side lengths of a single triangular mesh respectively; siIs the area of a single outer triangular mesh; st-mThe sum of the areas of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point is obtained, and M is the number of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point; starThe sum of the areas of the external triangular grids formed by all the central nodes of the sphere, wherein N is the number of all the external triangular grids;
s43, calculating the lightning stroke probability of the target lightning stroke contact point:
the lightning strike attachment probability of the local triangular grid surface element connected with the current lightning strike contact point is as follows:
the lightning partitioning method based on the lightning shortest path spatial geometric topological principle includes, in step S5:
s51, setting and adjusting coefficients a and b in the step S3, so that the radius of the lightning stroke sphere is gradually changed in a corresponding range, repeatedly executing the step S4 to judge and calculate the lightning stroke probability of the target lightning stroke point, and storing corresponding data;
s52, numerically adding and averaging the lightning stroke probabilities of the same target lightning stroke point in all the lightning stroke sphere radius states;
s53, expressing the lightning probability distribution and the intensity value of the target grid model by using a color difference graph, determining a threshold value of the lightning probability, and determining a region larger than the threshold value as a region 1, namely an initial lightning attachment point region, so as to obtain the distribution result of the aircraft lightning attachment points.
The lightning partitioning method based on the lightning shortest path space geometric topological principle includes, in step S53:
the threshold value is 10%.
Compared with the prior art, the invention has the following advantages:
after the target grid model is determined, the lightning attachment area and the lightning attachment level can be determined through one-time lightning attachment probability calculation of the full grid nodes, the calculation efficiency can be greatly improved, the calculation result is accurate, and the problems that simulation calculation under different attitude angles is carried out on the attitude of the target under different lightning leading states, and the calculation amount is very large are solved.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 shows an embodiment of the present invention in which a B757 aircraft CAD geometric model is imported into simulation software;
FIG. 3 shows an embodiment of the present invention in which a B757 aircraft CAD model is divided into mesh models in simulation software;
FIG. 4 is a schematic diagram of a lightning strike attachment point region search of a B757 aircraft in an embodiment of the invention;
FIG. 5 is a lightning outer envelope grid of a B757 aircraft in an embodiment of the present invention;
FIG. 6 is a diagram of B757 aircraft lightning strike attachment point distribution results in an embodiment of the present invention;
FIG. 7 is a schematic diagram of a grid pattern in an embodiment of the present invention;
FIG. 8 is a schematic diagram of a grid plane structure in an embodiment of the present invention;
fig. 9 is a schematic diagram of a node structure in the embodiment of the present invention.
Detailed Description
The present invention will now be further described by way of the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings.
As shown in fig. 1, the present invention provides a lightning partitioning method based on the spatial geometric topology principle of the shortest path of lightning, which comprises the following steps:
s1, dividing the target CAD model into grid models;
s2, reading the target grid model file and constructing a data matrix of the network node;
s3, establishing a central point coordinate data matrix of a target surface grid node tangent lightning stroke sphere, constructing the lightning stroke sphere and calculating the topological characteristic of a lightning stroke attachment point;
s4, judging and calculating the lightning stroke probability characteristic of the lightning stroke contact point on the surface of the airplane target according to the result of the step S3;
and S5, repeatedly executing the steps S3-S4 to calculate and count the lightning stroke probability of the same lightning stroke contact point under all the lightning stroke sphere radiuses, and obtaining the lightning stroke attachment point distribution result of the airplane target.
The steps S1 and S2 in the method belong to a general method and are necessary processes for realizing the steps of the method, and the steps S3-S5 are used for calculating the initial lightning attachment area by applying a lightning stroke sphere rolling model to a lightning stroke principle on an airplane and adopting a space geometric algorithm of a shortest path to solve the lightning attachment probability, so that the method is suitable for all-airplane lightning partitions of various aviation aircrafts, has strong applicability, simple, convenient and quick calculation and high accuracy, and can effectively provide reference basis for lightning protection design and verification tests and airworthiness conformance tests of the aviation aircrafts.
Examples
Taking a B757 airplane as an example, a specific implementation process of the above steps is described in detail:
the step S1 specifically includes:
and S11, establishing or importing a target three-dimensional CAD geometric model, wherein the CAD geometric model is as shown in figure 2, specifically, establishing or modifying an airplane target three-dimensional CAD geometric model in CAD software, and importing the target three-dimensional CAD geometric model in simulation software with a mesh division function.
S12, grid division is carried out on the target CAD model, specifically:
in simulation software with grid division performance, a triangular surface element is adopted to carry out discretization processing on an airplane target CAD model, the vertex of the triangular surface element is a node, and the nodes of adjacent triangular surface elements are required to be connected with each other. The premise of lightning partition is that a lightning attachment point is set, and any position of the target surface can be an initial attachment point of lightning, so that any surface element node in the target grid model is regarded as the initial attachment point of lightning stroke. In order to ensure the modeling precision of the target model and the calculation precision of the lightning subareas, the grid division is carried out by the average side length of the grid being about 0.2-1% of the length of the airplane model.
S13, storing the target grid division data into a grid model file in a common format, wherein the grid model file can be stored in a common format with a file format of nas, stl, asc and the like.
The step S2 specifically includes:
s21, reading the target grid model file, and establishing a data matrix of grid nodes, as shown in FIG. 2 and FIGS. 7-9:
and one triangular surface element is provided with three nodes, and coordinates are set for each node to form target grid model data. First, an origin is set, and the coordinates of the origin are (0, 0, 0). The origin may be located at a node position in the target grid or at a position outside the target grid. Reading coordinate data of each node in the target grid model, establishing a data matrix of the grid nodes of the target three-dimensional model, wherein the matrix has five columns, the first column of the matrix is the serial number of the grid nodes, the second column to the fourth column of the matrix are coordinates x, y and z respectively, the fifth column is a coordinate matrix value of the central point of a lightning stroke sphere of the target grid model, the initial value is 0, and the value is 1 later to indicate that the node is possible to be struck by lightning.
S22, establishing a data matrix of the target grid triangular surface element, specifically:
the data matrix of the triangular surface element has four columns, the first column of the matrix is the serial number of the triangular surface element, and the second column to the fourth column of the matrix are the serial numbers of the grid nodes forming the triangular surface element respectively.
The step S3 specifically includes:
s31, using the target grid node VmAs a calculation starting point, a lightning stroke sphere with the radius of R is established above the node, as shown in FIG. 4; in order to ensure the calculation precision of the lightning attachment probability, the selection formula of the radius R of the sphere is as follows:
R＝a×Ib (1)
where a is a coefficient in the range of (1-20) and b is a coefficient in the range of (0.2-1), the values of the coefficients depending on the model of the downlightning negative leader; i is lightning peak current;
and the lightning stroke sphere is tangent with the sphere taking the node as the center and a hexagonal combined surface element taking the node as the center (the hexagonal combined surface element consists of six triangular surface elements and takes a node VmAs a center), i.e., the slave node VmThe normal line led out passes through the center B of the ball body struck by lightning and the center point of the ball body reaches a node VmIs the radius R.
S32, calculating a node V from the center of the lightning stroke sphere to the target surfacekDistance R ofk-m-0：
In the formula, a target surface node VkThe coordinate is Ak(xk,yk,zk)；VmHas the coordinate of Am(xm,ym,zm) (ii) a And node VmTangential lightning stroke sphere BmThe coordinate of the central point of the grid model is Bm-0(xm-0,ym-o,zm-0)；
S33, calculating the nodes in the whole target grid model according to the step S32 to obtain a group of lightning stroke spheres BmJudging the shortest distance from the center of the lightning stroke sphere to the surface of the target by using a distance data matrix from the center to the surface of the target;
when k is m, Rk-m-0When data in the distance data matrix is smaller than R, the lightning stroke sphere is overlapped with other parts of the target at the node of the target, the node position is not attached by lightning stroke, and the central position of the lightning stroke sphere corresponding to the node is assigned to be 0; when the minimum data in the distance data matrix is r, and the point of tangency between the center of the lightning stroke sphere and the target surface is at a node VmThe tangential direction of the combined surface element at the six-surface angle indicates that the group of data is effective, the coordinate of the central point of the lightning stroke sphere at the moment is recorded, and the position is assigned as 1;
s34, repeating the steps S32 and S33, sequentially calculating the shortest distance from the center of a tangent sphere at each node in the target network model to the surface of the target, judging whether the sphere at the position is overlapped with other positions of the target or not, recording the coordinate of the center point of the lightning stroke sphere at the moment when the effective data condition in the step S33 is achieved, and establishing a lightning stroke external envelope network, wherein the coordinate data matrix of the center point of the target grid node tangent lightning stroke sphere is shown in figure 5;
s35, obtaining a topological data structure of the lightning strike attachment point, namely lightning external triangular grid data:
Bm-0＝Am+R×Nm (3)
in the formula: n is a radical ofmIs a target grid node VmNormalized normal vector coordinates of (a).
The step S4 specifically includes:
s41, searching and judging the number of the connected local triangular meshes at the lightning stroke position of the airplane model; the number is used for determining an external triangular mesh of all shared sphere center nodes of the current lightning strike contact point;
s42, calculating the external triangular mesh surface area of the target lightning strike contact point:
when node VmWhen the value of the coordinate matrix of the central point of the tangent lightning stroke sphere is 0, the node VmThe lightning stroke probability of the corresponding hexagonal combined surface element is 0; when the value of the coordinate matrix of the central point of the lightning stroke sphere is 1, the current lightning stroke contact point is obtained;
computing node VmS of the outer triangular mesh model correlationi、St-m、StarThe surface area, calculated as:
in the formula, ai、bi、ci3 side lengths of a single triangular mesh respectively; siIs the area of a single outer triangular mesh; st-mThe sum of the areas of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point is obtained, and M is the number of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point; starThe sum of the areas of the external triangular grids formed by all the central nodes of the sphere, wherein N is the number of all the external triangular grids;
s43, calculating the lightning stroke probability of the target lightning stroke contact point:
the lightning strike attachment probability of the local triangular grid surface element connected with the current lightning strike contact point is as follows:
the step S5 specifically includes:
s51, setting and adjusting coefficients a and b in the step S3, so that the radius of the lightning stroke sphere is gradually changed in a corresponding range, repeatedly executing the step S4 to judge and calculate the lightning stroke probability of the target lightning stroke point, and storing corresponding data;
s52, numerically adding and averaging the lightning stroke probabilities of the same target lightning stroke point in all the lightning stroke sphere radius states;
s53, expressing the lightning probability distribution and the intensity value of the target grid model by using a color difference graph, and determining a threshold value of the lightning probability, wherein the threshold value is 10% in the embodiment, and the area larger than the threshold value is an area 1, namely an initial lightning attachment point area, so as to obtain the distribution result of the aircraft lightning attachment points, and the result is shown in FIG. 6.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.
Claims (4)
1. A lightning partitioning method based on a lightning shortest path space geometric topological principle is characterized by comprising the following steps:
s1, dividing the target CAD model into grid models;
s2, readingTargetA grid model file is obtained, and a data matrix of network nodes is constructed;
s3, establishing a central point coordinate data matrix of a target surface grid node tangent lightning stroke sphere, constructing the lightning stroke sphere and calculating the topological characteristic of a lightning stroke attachment point;
s4, judging and calculating the lightning stroke probability characteristic of the lightning stroke contact point on the surface of the airplane target according to the result of the step S3;
s5, repeatedly executing the steps S3-S4 to calculate and count the lightning stroke probability of the same lightning stroke contact point under all the lightning stroke sphere radiuses, and obtaining the lightning stroke attachment point distribution result of the airplane target;
the step S3 specifically includes:
s31, using the target grid node VmAs a calculation starting point, establishing a lightning stroke sphere with R as a radius, wherein the selected formula of the radius R is as follows:
R＝a×Ib (1)
wherein a is a coefficient in the range of 1-20, b is a coefficient in the range of 0.2-1, the coefficient values depending on the model of the down lightning negative leader; i is lightning peak current;
s32, calculating a node V from the center of the lightning stroke sphere to the target surfacekDistance R ofk-m-0：
In the formula, a target surface node VkThe coordinate is Ak(xk,yk,zk)；VmHas the coordinate of Am(xm,ym,zm) (ii) a And node VmTangential lightning stroke sphere BmThe coordinate of the central point of the grid model is Bm-0(xm-0,ym-o,zm-0)；
S33, calculating the nodes in the whole target grid model according to the step S32 to obtain a group of lightning stroke spheres BmJudging the shortest distance from the center of the lightning stroke sphere to the surface of the target by using a distance data matrix from the center to the surface of the target;
when k is m, Rk-m-0When data in the distance data matrix is smaller than R, the lightning stroke sphere is overlapped with other parts of the target at the node of the target, the node position is not attached by lightning stroke, and the central position of the lightning stroke sphere corresponding to the node is assigned to be 0; when the minimum data in the distance data matrix is r, and the point of tangency between the center of the lightning stroke sphere and the target surface is at a node VmThe tangential direction of the combined surface element at the six-surface angle indicates that the group of data is effective, the coordinate of the central point of the lightning stroke sphere at the moment is recorded, and the position is assigned as 1;
s34, repeating the steps S32 and S33, sequentially calculating the shortest distance from the center of a tangent sphere at each node in the target network model to the surface of the target, judging whether the sphere at the position is overlapped with other positions of the target or not, recording the coordinate of the center point of the lightning stroke sphere at the moment when the effective data condition in the step S33 is achieved, and establishing a lightning stroke external envelope network, namely a coordinate data matrix of the center point of the target grid node tangent lightning stroke sphere;
s35, obtaining a topological data structure of the lightning strike attachment point, namely lightning external triangular grid data:
Bm-0＝Am+R×Nm (3)
in the formula: n is a radical ofmIs a target grid node VmNormalized normal vector coordinates of (a).
2. The lightning partitioning method based on the lightning shortest path spatial geometric topological principle of claim 1, wherein the step S4 specifically comprises:
s41, searching and judging the number of the connected local triangular meshes at the lightning stroke position of the airplane model; the number is used for determining an external triangular mesh of all shared sphere center nodes of the current lightning strike contact point;
s42, calculating the external triangular mesh surface area of the target lightning strike contact point:
when node VmWhen the value of the coordinate matrix of the central point of the tangent lightning stroke sphere is 0, the node VmThe lightning stroke probability of the corresponding hexagonal combined surface element is 0; when the value of the coordinate matrix of the central point of the lightning stroke sphere is 1, the current lightning stroke contact point is obtained;
computing node VmS of the outer triangular mesh model correlationi、St-m、StarThe surface area, calculated as:
in the formula, ai、bi、ci3 side lengths of a single triangular mesh respectively; siIs the area of a single outer triangular mesh; st-mThe sum of the areas of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point is obtained, and M is the number of the external triangular grids of all the shared sphere center nodes of the current lightning strike contact point; starFormed by central nodes of all spheresThe sum of the areas of the external triangular meshes, wherein N is the number of all the external triangular meshes;
s43, calculating the lightning stroke probability of the target lightning stroke contact point:
the lightning strike attachment probability of the local triangular grid surface element connected with the current lightning strike contact point is as follows:
3. the lightning partitioning method based on the spatial geometrical topological principle of the lightning shortest path according to claim 2, wherein the step S5 specifically comprises:
s51, setting and adjusting coefficients a and b in the step S3, so that the radius of the lightning stroke sphere is gradually changed in a corresponding range, repeatedly executing the step S4 to judge and calculate the lightning stroke probability of the target lightning stroke point, and storing corresponding data;
s52, numerically adding and averaging the lightning stroke probabilities of the same target lightning stroke point in all the lightning stroke sphere radius states;
s53, expressing the lightning probability distribution and the intensity value of the target grid model by using a color difference graph, determining a threshold value of the lightning probability, and determining a region larger than the threshold value as a region 1, namely an initial lightning attachment point region, so as to obtain the distribution result of the aircraft lightning attachment points.
4. The lightning zoning method based on the lightning shortest path spatial geometric topological principle of claim 3, wherein in the step S53:
the threshold value is 10%.
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