CN112287572B - Complex system and lightning stroke direct effect protection optimization and verification method and device thereof - Google Patents
Complex system and lightning stroke direct effect protection optimization and verification method and device thereof Download PDFInfo
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Abstract
The disclosure relates to a complex system and a lightning direct effect protection optimization and verification method and device thereof. The lightning direct effect protection optimization and verification method of the complex system comprises the following steps: determining the overall lightning current conduction path and characteristic structure of the complex system; according to the lightning current conduction path and the simplified modeling principle, simplifying and modeling is carried out on the whole complex system model, and the whole current distribution simulation is carried out on the simplified system model; and carrying out fine modeling on the extracted characteristic structure to obtain a quantification result of lightning damage simulation of the characteristic structure. The method and the device can perform rapid iterative optimization with the structural design scheme, accurately reflect the real lightning strike working condition level and obtain the overall optimal solution to the system; meanwhile, the test cost in the research and development process is greatly reduced.
Description
Technical Field
The disclosure relates to the field of aviation lightning protection, in particular to a complex system and a lightning direct effect protection optimization and verification method and device thereof.
Background
With the application of composite materials to aircraft skins and frame structures in a large number in recent years, the performance of the aircraft structure is improved continuously, meanwhile, lightning protection design and verification work are difficult, and particularly, large-scale complex systems such as wing fuel systems, nacelle systems and the like are used for a large number of composite materials, the structural characteristics, states, structural performances and the like which need to be verified when lightning work is carried out are extremely large, and in this case, the carrying out of the lightning work is also particularly difficult according to the means of a metal aircraft which only depends on test verification. The number of test pieces and the number of tests become extremely large due to the diversity of the damage characteristics and structural characteristics of the lightning tests in the product research and development stage, so that the cost becomes extremely high while the lightning protection design and verification work difficulty is increased.
Disclosure of Invention
The inventors found through research that: at present, the design optimization and verification means aiming at the lightning direct effect protection of the aircraft structure mainly carry out a typical structural part level test and a part level test according to the SAE ARP5416 standard: for a direct lightning stroke area structure such as a composite material skin structure, a lightning stroke damage result is obtained mainly by means of a typical structural member arc introduction test, nondestructive testing is conducted on a test piece to determine a damage range, residual strength assessment is conducted on the test piece with damage according to the residual strength requirement, wherein the assessment current selection can refer to the SAE ARP5412 standard, the outstanding problem is that the damage depth of the composite material is difficult to measure through damage measurement means such as C scanning and the like because the composite material skin belongs to a thin-wall structure, the damage depth has a great influence on the residual strength of the composite material, and an accurate optimization space of the structure cannot be determined.
The design optimization and verification means for key structures such as an internal hinge structure and the like on a lightning current conduction path are mainly to conduct current conduction tests on structural members according to partition requirements, and the outstanding problem is that two conditions exist if current amplitude values are still selected as assessment currents according to SAE ARP5412 standards because the structural members are arranged in a system and are not in direct lightning stroke areas: 1. if only the checking structure is selected as a test object to conduct a conduction test, excessive checking can be caused by the fact that the conduction current passes through the checking structure completely, and the design result is conservative. 2. If the whole body is selected as a test object to conduct a conduction test, the full-size current has the risk of causing structural damage, and the test cost is too high.
In view of at least one of the above technical problems, the present disclosure provides a complex system and a lightning direct effect protection optimization and verification method and device thereof, which can perform rapid iterative optimization with a structural design scheme and accurately reflect a real lightning working condition level.
According to one aspect of the present disclosure, there is provided a method for optimizing and verifying lightning strike direct effect protection of a complex system, comprising:
determining the overall lightning current conduction path and characteristic structure of the complex system;
according to the lightning current conduction path and the simplified modeling principle, simplifying and modeling is carried out on the whole complex system model, and the whole current distribution simulation is carried out on the simplified system model;
and carrying out fine modeling on the extracted characteristic structure to obtain a quantification result of lightning damage simulation of the characteristic structure.
In some embodiments of the present disclosure, the performing the overall current distribution simulation on the simplified system model includes:
and determining lightning out-points and in-points at the positions of the aircraft by combining a complex system, so as to form a current conducting loop.
In some embodiments of the present disclosure, the complex system lightning direct effect protection optimization and verification method further comprises:
and carrying out overall estimation and optimization of the lightning protection scheme according to the overall current distribution simulation result.
In some embodiments of the present disclosure, the complex system lightning direct effect protection optimization and verification method further comprises:
deriving a current component of the feature structure according to the overall current distribution simulation result;
and performing damage test of the characteristic structure according to the current component of the characteristic structure.
In some embodiments of the present disclosure, the complex system lightning direct effect protection optimization and verification method further comprises:
comparing the quantitative result of the lightning damage simulation of the characteristic structure with the damage test result of the characteristic structure standard test piece, and analyzing the accuracy of the protection effect;
optimizing and determining a lightning protection scheme of the characteristic structure according to an accuracy analysis result of the protection effect;
and (5) performing a verification test of the overall lightning protection effect of the complex system.
In some embodiments of the present disclosure, the complex system is a complex system comprising a composite skin and a frame structure.
In some embodiments of the present disclosure, the composite material is a carbon fiber reinforced composite material.
In some embodiments of the present disclosure, the obtaining the quantification of lightning damage simulation of the feature includes:
measuring anisotropic conductivity of the composite material and the metal mesh;
establishing a mesh subdivision principle aiming at model characteristics;
setting a physical field and boundary conditions and selecting a transient solver suitable for model solving;
lightning damage is quantified by temperature distribution.
In some embodiments of the present disclosure, the measuring the anisotropic conductivity of the composite and the metal mesh comprises:
equivalent metal net is formed into a flat plate layer, conductivity in the length direction and the width direction of the metal net is measured, and equivalent conductivity in the thickness direction of the metal net is calculated by adopting a numerical calculation method;
the conductivity of the composite material in the fiber direction, perpendicular to the fiber direction and in the thickness direction was measured.
According to another aspect of the present disclosure, there is provided a complex system lightning direct effect protection optimization and verification device, comprising:
the path and characteristic structure determining module is used for determining the overall lightning current conduction path and characteristic structure of the complex system;
the integral simplified modeling module is used for carrying out simplified modeling on the integral model of the complex system according to the lightning current conduction path and the simplified modeling principle, and carrying out integral current distribution simulation on the simplified system model;
and the fine modeling module is used for carrying out fine modeling on the extracted characteristic structure and obtaining the quantification result of lightning damage simulation of the characteristic structure.
In some embodiments of the present disclosure, the complex system lightning direct effect protection optimization and verification device is configured to perform operations to implement the complex system lightning direct effect protection optimization and verification method described in any of the embodiments above.
According to another aspect of the present disclosure, there is provided a complex system lightning direct effect protection optimization and verification device, comprising:
a memory for storing instructions;
and the processor is used for executing the instructions, so that the complex system lightning direct effect protection optimization and verification device executes the operation of realizing the complex system lightning direct effect protection optimization and verification method according to any embodiment.
According to another aspect of the present disclosure, there is provided a complex system comprising a complex system lightning direct effect protection optimization and verification device as described in any of the embodiments above.
According to another aspect of the disclosure, there is provided a computer readable storage medium storing computer instructions that when executed by a processor implement a method of optimizing and validating lightning strike direct effect protection of a complex system according to any of the embodiments described above.
The method and the device can perform rapid iterative optimization with the structural design scheme, accurately reflect the real lightning strike working condition level and obtain the overall optimal solution to the system; meanwhile, the test cost in the research and development process is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.
FIG. 1 is a schematic diagram of some embodiments of a lightning direct effect protection optimization and verification method of the complex system of the present disclosure.
FIG. 2 is a schematic diagram of further embodiments of the lightning direct effect protection optimization and verification method of the complex system of the present disclosure.
FIG. 3 is a flow chart of a direct effect simulation analysis of a feature lightning in some embodiments of the disclosure.
FIG. 4 is a schematic diagram of some embodiments of a lightning strike direct effect protection optimization and verification device of the present disclosure.
FIG. 5 is a schematic diagram of further embodiments of the lightning direct effect protection optimization and verification device of the complex system of the present disclosure.
Detailed Description
The following description of the technical solutions in the embodiments of the present disclosure will be made clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure, and it is apparent that the described embodiments are only some embodiments of the present disclosure, not all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. Based on the embodiments in this disclosure, all other embodiments that a person of ordinary skill in the art would obtain without making any inventive effort are within the scope of protection of this disclosure.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless it is specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
The inventors found through research that: in the related technology, due to factors such as complex structure, large size, multiple structural features and the like of a research object, the difficulty and cost of directly carrying out fine modeling calculation or test on the whole object are very high, and when lightning stroke protection design and verification are carried out on a direct lightning stroke area structure such as a composite material skin structure, the prominent problem is that the composite material skin belongs to a thin-wall structure, the damage depth of the composite material is difficult to measure by a C-scanning and other damage measurement means, and the damage depth has a great influence on the residual strength of the composite material, so that the accurate optimization space of the structure cannot be determined only by the related technology test means.
The outstanding problem of design optimization and verification of key structures such as an internal hinge structure and the like on a lightning current conduction path is that because structural members are arranged in a system and are not in direct lightning stroke areas, if a related technology test means is adopted, if only an examination structure is selected as a test object to conduct a conduction test, excessive examination can be caused when the conduction current passes through the examination structure, the design result is conservative, if the whole is selected as the test object to conduct the conduction test, the whole-size current has the risk of damaging the whole structure, and the test cost is too high.
In view of at least one of the above technical problems, the present disclosure provides a complex system and lightning strike direct effect protection optimization and verification method and device thereof.
The method and the device for optimizing and verifying the lightning direct effect protection of the complex system are described in the following through specific embodiments.
FIG. 1 is a schematic diagram of some embodiments of a lightning direct effect protection optimization and verification method of the complex system of the present disclosure. Preferably, the present embodiment may be performed by the complex system lightning strike direct effect protection optimization and verification device of the present disclosure. The lightning direct effect refers to the physical effect of the aircraft and equipment caused by the direct attachment of the lightning channel to the aircraft and by the conduction of lightning current; the direct effect of lightning is a multi-physical field problem, and when lightning strikes act on an aircraft, the structure often has electromagnetic, heating and stress effects while current passes through.
The method of the embodiment of fig. 1 may comprise the steps of:
and 11, determining the overall lightning current conducting path and the characteristic structure of the complex system, and extracting the characteristic structure to be inspected on the conducting path.
In some embodiments of the present disclosure, the complex system may be a complex system comprising a composite skin and a frame structure.
In some embodiments of the present disclosure, the composite material may be CFRP (Carbon Fiber Reinforced Polymer/Plastic, carbon fiber reinforced composite).
And step 12, simplifying modeling is carried out on the complex system overall model according to the lightning current conduction path and the simplified modeling principle, and overall current distribution simulation is carried out on the simplified system model.
In some embodiments of the present disclosure, step 12 may include:
step 121, simplified modeling is performed on the overall system model according to the conduction path and the simplified modeling principle, and an overall lightning path simplified model of the complex object is established.
In some embodiments of the present disclosure, step 121 may include: and determining a lightning outlet point and a lightning inlet point at the position of the aircraft according to the lightning subareas and the complex system, and forming a current conduction loop.
In some embodiments of the present disclosure, the step of determining the lightning out-point and in-point in step 121 may include: the lightning distribution formed by the access points is selected to inspect all areas of the system; the lightning threat created by the selected access points is the most severe.
At step 122, a lightning conduction or arc striking model of the feature is determined.
In some embodiments of the present disclosure, the feature structure requires the establishment of a current conduction model and a current striking model, the model settings of which are consistent with the test, and reference may be made to the selection of test criteria.
In some embodiments of the present disclosure, the selected features of lightning 1 and 2 regions require the creation of a lightning current striking model, and the lightning 3 region and system internal structures create a current conduction model. Wherein, lightning strike zone 1: the aircraft surfaces in this area are most vulnerable to lightning strikes (inlet and outlet); lightning strike zone 2: the aircraft surface of this area is most susceptible to sweeping by lightning strikes starting from area 1; lightning strike zone 3: including all aircraft surfaces except regions 1 and 2, the likelihood of lightning strikes is low. But the area is still traversed by the current at the two lightning strike points (in and out).
Step 123, performing overall current distribution simulation on the simplified system model.
In some embodiments of the present disclosure, the simulation result of step 123 may be used as a basis for performing an optimization design on the overall lightning current conduction path, and meanwhile, a current component of the non-direct lightning strike area feature structure is obtained as a basis for evaluating current, which is used for a lightning damage test and a simulation analysis of the next feature structure, respectively.
And 13, carrying out fine modeling on the extracted characteristic structure to obtain a quantification result of lightning damage simulation of the characteristic structure.
In some embodiments of the present disclosure, step 13 may include:
step 131, measuring the anisotropic conductivity of the composite material and the metal mesh.
In simulation calculation, material parameters are critical, and whether the material parameters are reasonable or not directly determines the accuracy of simulation solution. The key materials for solving the lightning direct effect problem are mainly intrinsic conductivity, heat conduction coefficient, heat capacity and the like of the material. The conductivity of the metal net and the composite material is obtained by a measuring method, other material parameters can be measured by a professional laboratory, or data of an authoritative measuring laboratory are quoted, and the actual calibration is combined in the simulation process.
In some embodiments of the present disclosure, step 131 may include step a and step b, wherein:
and a, equivalent metal net is formed into a plate layer, conductivity in the length direction and the width direction of the metal net is measured, and equivalent conductivity in the thickness direction of the metal net is calculated by adopting a numerical calculation method.
In some embodiments of the present disclosure, the metal mesh is fine and complex in structure and difficult in finite element modeling during simulation calculation, and the metal mesh is equivalent to a plate layer. Because the process has great influence on the conductivity of the metal net in production, the intrinsic conductivity of the equivalent metal net needs to be obtained through actual measurement.
Of metal meshesThe structural characteristics lead to the variability of the conductivity, so that the conductivity in three directions, namely sigma, of the length direction x, the length direction y and the thickness direction z of the metal net need to be measured during measurement xx ，σ yy ，σ zz The test method is as follows:
for sigma xx ，σ yy The sample is made taking into account the uniform spread of the current and the test errors. It is recommended to make a plurality of rectangular test pieces with a large aspect ratio, and to make measurements separately.
In some embodiments of the present disclosure, step a may comprise:
and a step a1, performing zero setting calibration on the measuring device. The method comprises the steps of carrying out a first treatment on the surface of the
And a2, clamping two ends of the test piece by using a clamp, reading out the resistance value of the test piece on a display screen, and recording the measured resistance value.
Step a3, calculating the corresponding resistivity ρ by the following formula (1), averaging the resistivity ρ, and calculating the conductivity σ by the formula (2). Wherein ρ is resistivity, R is resistance, S is cross-sectional area, L is specimen length, σ is conductivity.
Conductivity sigma in thickness direction of metal copper net zz It is difficult to test a material by injecting a current through both positive and negative electrodes into the material, where the three resistors are connected in series in the circuit. In general, the conductivity of the metal copper mesh is in the order of 107S/m, and the resistivity is very small, so that the influence of the resistance of the measuring electrode on the total resistance is large, the measured resistance is large in difference with the actual resistance of the metal copper mesh, and the calculated conductivity error is also large. Conductivity sigma in thickness direction of metallic copper net zz The calculation is performed using a numerical method. The current of 1A flows uniformly from the upper surface of the model to the lower surfaceThe surface flows out. And obtaining the terminal resistance through simulation calculation, and enabling the metal net units to be equivalent to rectangular units with the same thickness and consistent length and width. And calculating the equivalent conductivity in the z direction from the formula (1) and the formula (2).
And b, measuring the conductivity of the composite material in the fiber direction, the vertical fiber direction and the thickness direction.
In some embodiments of the present disclosure, the composite is equivalently modeled, with the composite being set to the x-direction along the fiber direction, the y-direction perpendicular to the fiber direction, and the thickness direction being set to the z-direction. Because the composite material has anisotropy, the conductivity in three directions of xyz needs to be measured, and the structural attribute of the material is added, the testing method of the step b can comprise the following steps:
σ xx ，σ yy the test method of (2) is mainly referred to the aerospace industry standard of China aerospace industry head, and the resistivity test method of the carbon fiber and the composite material thereof (QJ 3074-98). The test principle is a double-probe method test, and the test method is based on ohm's law. Square (rectangle or other) samples were made, two metal electrodes were sandwiched on both sides of the composite, and the resistance was tested with a high precision resistance tester. When the metal electrode is used, the two ends of the CFRP material are polished, so that the carbon fiber is completely exposed, the metal electrode is connected with the carbon fiber through conductive adhesive, and the electrode is clamped by a pressure clamp, so that the electrode is fully contacted with the CFRP material.
The test scheme is equivalent to a series circuit, and the relation between the test resistance and the metal electrode and the resistance of the CFRP material is as follows:
R＝R1+R2+R3 (3)
wherein R is the resistance measured by a megameter, R1 is the resistance of the left metal electrode, R2 is the resistance of the CFRP test piece, and R3 is the resistance of the right metal electrode.
The CFRP material resistance is therefore:
R2＝R-R1-R3 (4)
the resistivity of the CFRP material is as follows:
CFRP material conductivity:
conductivity sigma in CFRP material thickness direction zz Current is injected into the material through the positive and negative electrodes, and the three resistors are connected in series in the circuit. Wherein R1 is the resistance of the left metal electrode, R2 is the resistance of the CFRP test piece, R3 is the resistance of the right metal electrode, R is the resistance measured by a megameter, and each resistance accords with the relation of the formula (3). When the metal electrode is used, the upper surface and the lower surface of the CFRP material are polished, so that the carbon fiber is completely exposed, the metal electrode is connected with the carbon fiber by using conductive adhesive, and the electrode is clamped by using a pressure clamp, so that the electrode is fully contacted with the CFRP material. The size of the metal electrode is larger than or equal to that of the CFRP test piece, so that the current is ensured to uniformly spread on the CFRP test piece.
The resistance R is measured by a direct current resistance meter, the resistance R2 of the CFRP material is obtained by a formula (4), and the resistivity ρ is obtained by formulas (5) and (6) respectively z And conductivity sigma zz 。
In any direction of measurement, the measurement error is considered, a plurality of CFRP material test pieces are recommended to be manufactured, the test is performed respectively, the measured resistance value is recorded, the resistivity rho is calculated, and the conductivity sigma is calculated after averaging.
Step 132, formulating mesh subdivision principle for model features.
In some embodiments of the present disclosure, step 132 may include: and selecting a proper mesh for the model features, designing the mesh for the model, and making a mesh rule.
Step 133, setting physical field and boundary conditions and selecting a transient solver suitable for model solving.
In step 134, the lightning damage is quantified by temperature distribution.
In some embodiments of the present disclosure, step 134 may include: calculating quantified physical quantities such as current distribution, temperature distribution, stress distribution, electromagnetic field distribution and the like; because the damage of the thin-wall structure of the composite material is mainly caused by instantaneous high temperature, the damage can be quantified through temperature distribution.
In some embodiments of the present disclosure, after step 13, the complex system lightning direct effect protection optimization and verification method may further include: and the numerical calculation result is required to be combined with the analysis result and the comparison of the test result of the standard test piece for accuracy analysis.
According to the lightning direct effect protection optimization and verification method for the complex system, lightning current path simulation is conducted through the overall simplified model, local current is collected for current conduction assessment, feasibility of a lightning protection scheme is verified through fine simulation and experimental analysis of a local structure, rapid repeated iteration and accurate optimization design can be conducted with design results in a product research and development stage, and finally experimental verification of overall lightning protection effect is conducted on the overall complex system.
The research method of the embodiment of the disclosure can greatly increase the reliability of the design of the direct effect protection of the lightning stroke of the complex system, simultaneously furthest reduce the test cost of repeated tests caused by design iteration, and a series of typical sample pieces can be accumulated into a model library to play a great role in subsequent designs. The method for researching the embodiment of the disclosure has strong guiding and reference significance for similar design optimization and verification work of lightning direct effect protection of complex systems with composite material skins and frame structures.
FIG. 2 is a schematic diagram of further embodiments of the lightning direct effect protection optimization and verification method of the complex system of the present disclosure. Preferably, the present embodiment may be performed by the complex system lightning strike direct effect protection optimization and verification device of the present disclosure. The method of the embodiment of fig. 2 may comprise the steps of:
step 201, determining the overall lightning current conduction path of the complex system; step 202 and step 207 are then performed.
In some embodiments of the present disclosure, the complex system may be a complex system comprising a composite skin and a frame structure.
In some embodiments of the present disclosure, the composite material may be CFRP (Carbon Fiber Reinforced Polymer/Plastic, carbon fiber reinforced composite).
Step 202, simplified modeling is carried out on the complex system overall model according to the lightning current conduction path and the simplified modeling principle.
Step 203, performing overall current distribution simulation on the simplified system model; step 204 and step 205 are then performed.
And 204, carrying out overall estimation and optimization of the lightning protection scheme according to the overall current distribution simulation result.
Step 205, deriving a current component of the feature structure according to the overall current distribution simulation result; step 206 and step 209 are then performed.
Step 206, performing a damage test of the feature structure according to the current component of the feature structure; step 210 is then performed.
In step 207, the feature structure to be inspected on the conductive path is extracted.
And step 208, carrying out fine modeling on the extracted characteristic structure.
And step 209, obtaining a quantification result of lightning damage simulation of the characteristic structure.
And 210, comparing the quantitative result of the lightning damage simulation of the characteristic structure with the damage test result of the characteristic structure standard test piece, and analyzing the accuracy of the protection effect.
Step 211, optimizing and determining the lightning protection scheme of the characteristic structure according to the accuracy analysis result of the protection effect.
And step 212, performing a verification test of the overall lightning protection effect of the complex system.
FIG. 3 is a flow chart of a direct effect simulation analysis of a feature lightning in some embodiments of the disclosure. The method for analyzing the lightning direct effect simulation of the characteristic structure of the embodiment of fig. 3 may comprise the following steps:
in step 301, a simulation object is determined. I.e. to determine the features on the conductive path that need to be investigated.
Step 302, a simulation tool is selected.
Step 303, a simulation model is built. Namely, the extracted feature structure is modeled in detail. Thereafter, steps 304-306 are performed.
Step 304, measuring a material parameter; step 307 is then performed.
In some embodiments of the present disclosure, step 304 may include: the anisotropic conductivity of the composite and metal mesh was measured.
Step 305, designing a model grid; step 307 is then performed.
In some embodiments of the present disclosure, step 305 may include: and selecting a proper mesh for the model features, designing the mesh for the model, and making a mesh rule.
Step 306, setting physical field and boundary conditions; step 307 is then performed.
Step 307, selecting and setting a solution method.
In some embodiments of the present disclosure, step 307 may include: a transient solver suitable for model solving is selected.
Step 308, analyzing the accuracy of the calculation result.
Step 309, analyzing the simulation result; step 313 is then performed.
Step 310, comparing the numerical result and the analysis result; step 312 is then performed.
Step 311, performing typical structure simulation and test comparison; after which a step 312 is performed in which,
in some embodiments of the present disclosure, step 311 may include: and the numerical calculation result is required to be combined with the analysis result and the comparison of the test result of the standard test piece for accuracy analysis.
Step 312, evaluating the credibility of the simulation.
Step 313, quantifying lightning damage by the physical field.
In some embodiments of the present disclosure, step 313 may include: calculating quantified physical quantities such as current distribution, temperature distribution, stress distribution, electromagnetic field distribution and the like; because the damage of the thin-wall structure of the composite material is mainly caused by instantaneous high temperature, the damage can be quantified through temperature distribution.
And 314, collecting the simulation result.
According to the embodiment of the disclosure, the whole lightning current conduction path and the characteristic structure can be determined according to the partition and the structural characteristics in the product research and development stage, the system whole model is subjected to simplified modeling according to the conduction path and the simplified modeling principle, and the lightning conduction or arc striking model of the complex object whole lightning path simplified model and the characteristic structure is established. And carrying out overall current distribution simulation on the simplified system model, wherein a simulation result can be used as a basis for carrying out optimal design on an overall lightning current conducting path, and meanwhile, current components of the non-direct lightning stroke area characteristic structure are obtained and used as a basis for checking current to be respectively used for lightning damage test and simulation analysis of the next characteristic structure.
According to the embodiment of the disclosure, the extracted characteristic structure is subjected to fine modeling, and the following steps are performed on the composite material skin structure to obtain a quantifiable damage result: 1. actually measuring the anisotropic conductivity of the composite material and the metal net; 2. selecting a proper mesh for the model features, designing the model to form a mesh, and formulating a mesh principle; 3. setting a physical field and boundary conditions and selecting a transient solver suitable for model solving; 4. the quantified physical quantity such as current distribution, temperature distribution, stress distribution, electromagnetic field distribution and the like is calculated, and as the damage of the thin-wall structure of the composite material is mainly caused by instantaneous high temperature, the damage can be quantified through the temperature distribution; 5. and the numerical calculation result is required to be combined with the analysis result and the comparison of the test result of the standard test piece for accuracy analysis.
Therefore, the research method of the embodiment of the disclosure can greatly increase the reliability of the design of the direct effect protection of the lightning stroke of the complex system, simultaneously furthest reduce the test cost of repeated tests caused by design iteration, and a series of typical sample pieces can be accumulated into a model library to play a great role in subsequent designs. The method for researching the embodiment of the disclosure has strong guiding and reference significance for similar design optimization and verification work of lightning direct effect protection of complex systems with composite material skins and frame structures.
FIG. 4 is a schematic diagram of some embodiments of a lightning strike direct effect protection optimization and verification device of the present disclosure. As shown in fig. 4, the complex system lightning strike direct effect protection optimization and verification device of the present disclosure may include a path and feature determination module 41, an overall simplified modeling module 42, and a refined modeling module 43, wherein:
the path and feature determination module 41 is used to determine the overall lightning current conduction path and feature of the complex system.
In some embodiments of the present disclosure, the complex system may be a complex system comprising a composite skin and a frame structure.
In some embodiments of the present disclosure, the composite material may be CFRP.
The overall simplified modeling module 42 is configured to perform simplified modeling on the complex system overall model according to the lightning current conduction path and the simplified modeling principle, and perform overall current distribution simulation on the simplified system model.
In some embodiments of the present disclosure, the global simplified modeling module 42 may be configured to simplified model the system global model according to conduction paths and simplified modeling principles to create a complex object global lightning path simplified model; determining a lightning conduction or arc striking model of the feature structure; and carrying out overall current distribution simulation on the simplified system model.
The refinement modeling module 43 is configured to perform refinement modeling on the extracted feature structure, and obtain a quantification result of lightning damage simulation of the feature structure.
In some embodiments of the present disclosure, refinement modeling module 43 may be used to refine model the extracted feature structure; measuring anisotropic conductivity of the composite material and the metal mesh; establishing a mesh subdivision principle aiming at model characteristics; setting a physical field and boundary conditions and selecting a transient solver suitable for model solving; setting a physical field and boundary conditions and selecting a transient solver suitable for model solving; and setting physical fields and boundary conditions, and selecting a transient solver suitable for model solving.
In some embodiments of the present disclosure, the complex system lightning direct effect protection optimization and verification device is configured to perform operations to implement the complex system lightning direct effect protection optimization and verification method described in any of the embodiments above (e.g., any of the embodiments of fig. 1-3).
FIG. 5 is a schematic diagram of further embodiments of the lightning direct effect protection optimization and verification device of the complex system of the present disclosure. As shown in fig. 5, the complex system lightning strike direct effect protection optimization and verification device of the present disclosure may include a memory 51 and a processor 52, wherein:
a memory 51 for storing instructions.
A processor 52 for executing the instructions to cause the complex system lightning direct effect protection optimization and verification device to perform operations implementing the complex system lightning direct effect protection optimization and verification method described in any of the embodiments described above (e.g., any of the embodiments of fig. 1-3).
Based on the lightning direct effect protection optimizing and verifying device for the complex system provided by the embodiment of the disclosure, lightning current path simulation is performed through the overall simplified model, local current is collected for current conduction assessment, feasibility of a lightning protection scheme is verified through fine simulation and experimental analysis of a local structure, rapid repeated iteration and accurate optimization design can be performed with a design result in a product research and development stage, and finally experimental verification of overall lightning protection effect is performed on the overall complex system.
The embodiment of the disclosure can greatly increase the reliability of the design of the lightning direct effect protection of the complex system, simultaneously furthest reduce the test cost of trial and error caused by design iteration, and a series of typical sample pieces can be accumulated into a model library to play a great role in subsequent designs. The design optimization and verification work of the lightning stroke direct effect protection of the complex system with the composite material skin and the frame structure, which are similar to the embodiment of the disclosure, have strong guiding and reference significance.
According to another aspect of the present disclosure, there is provided a complex system comprising a complex system lightning direct effect protection optimization and verification device as described in any one of the embodiments described above (e.g., the embodiment of fig. 4 or 5).
Based on the complex system provided by the embodiment of the disclosure, the reliability of the lightning direct effect protection design of the complex system can be greatly increased, meanwhile, the test cost of trial and error caused by design iteration is reduced to the greatest extent, and a series of typical sample pieces can be accumulated into a model library to play a great role in subsequent designs. The design optimization and verification work of the lightning stroke direct effect protection of the complex system with the composite material skin and the frame structure, which are similar to the embodiment of the disclosure, have strong guiding and reference significance.
According to another aspect of the disclosure, a computer readable storage medium is provided, wherein the computer readable storage medium stores computer instructions that, when executed by a processor, implement a method of complex system lightning direct effect protection optimization and verification as described in any of the embodiments above (e.g., any of the embodiments of fig. 1-3).
Based on the computer readable storage medium provided by the embodiment of the disclosure, the reliability of the design for protecting the direct effect of the lightning stroke of the complex system can be greatly increased, meanwhile, the test cost of trial and error caused by design iteration is reduced to the greatest extent, and a series of typical sample pieces can be accumulated into a model library to play a great role in subsequent designs. The design optimization and verification work of the lightning stroke direct effect protection of the complex system with the composite material skin and the frame structure, which are similar to the embodiment of the disclosure, have strong guiding and reference significance.
The complex system lightning direct effect protection optimization and verification device described above may be implemented as a general purpose processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof for performing the functions described herein.
Thus far, the present disclosure has been described in detail. In order to avoid obscuring the concepts of the present disclosure, some details known in the art are not described. How to implement the solutions disclosed herein will be fully apparent to those skilled in the art from the above description.
Those of ordinary skill in the art will appreciate that all or a portion of the steps implementing the above embodiments may be implemented by hardware, or may be implemented by a program indicating that the relevant hardware is implemented, where the program may be stored on a computer readable storage medium, where the storage medium may be a read only memory, a magnetic disk or optical disk, etc.
The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.
Claims (12)
1. A lightning direct effect protection optimization and verification method for a complex system is characterized by comprising the following steps:
determining the overall lightning current conduction path and the characteristic structure of a complex system, and extracting the characteristic structure to be inspected on the conduction path, wherein the complex system comprises a composite material skin and a frame structure;
according to the lightning current conduction path and the simplified modeling principle, simplifying and modeling is carried out on the whole complex system model, and the whole current distribution simulation is carried out on the simplified system model;
carrying out fine modeling on the extracted characteristic structure to obtain a quantification result of lightning damage simulation of the characteristic structure;
the simplified modeling of the complex system overall model according to the lightning current conduction path and the simplified modeling principle comprises the following steps:
performing simplified modeling on the whole system model according to the conduction path and the simplified modeling principle, and establishing a simplified model of the whole lightning path of the complex object;
determining a lightning current conduction model and a lightning current arc striking model of a characteristic structure, wherein the lightning current arc striking model of the characteristic structure is selected by a first lightning zone and a second lightning zone, the lightning current conduction model is built by a third lightning zone and a system internal structure, and the surface of an aircraft in the first lightning zone is most susceptible to lightning strike; the aircraft surface selected for the second lightning zone is most susceptible to sweeping by lightning strikes starting from the first lightning zone; the third lightning zone comprises all aircraft surfaces except the first lightning zone and the second lightning zone, and the third lightning zone is penetrated by the current of the lightning outlet point and the lightning inlet point;
carrying out overall current distribution simulation on the simplified system model;
the quantification result of the lightning damage simulation of the obtained characteristic structure comprises the following steps:
measuring anisotropic conductivity of the composite material and the metal mesh;
establishing a mesh subdivision principle aiming at model characteristics;
setting a physical field and boundary conditions and selecting a transient solver suitable for model solving;
lightning damage is quantified by temperature distribution.
2. The method for optimizing and validating lightning direct effect protection of a complex system of claim 1, wherein said simulating the overall current distribution of a simplified system model comprises:
and determining lightning out-points and in-points at the positions of the aircraft by combining a complex system, so as to form a current conducting loop.
3. The method for optimizing and validating lightning direct effect protection of a complex system of claim 1, further comprising:
and carrying out overall estimation and optimization of the lightning protection scheme according to the overall current distribution simulation result.
4. A method of optimizing and validating lightning direct effect protection of a complex system according to any one of claims 1-3, further comprising:
deriving a current component of the feature structure according to the overall current distribution simulation result;
and performing damage test of the characteristic structure according to the current component of the characteristic structure.
5. The method for optimizing and validating lightning direct effect protection of a complex system of claim 4, further comprising:
comparing the quantitative result of the lightning damage simulation of the characteristic structure with the damage test result of the characteristic structure standard test piece, and analyzing the accuracy of the protection effect;
optimizing and determining a lightning protection scheme of the characteristic structure according to an accuracy analysis result of the protection effect;
and (5) performing a verification test of the overall lightning protection effect of the complex system.
6. A complex system lightning direct effect protection optimization and verification method according to any of the claims 1-3, characterized in that,
the composite material is a carbon fiber reinforced composite material.
7. A method of optimizing and validating protection against direct effects of a lightning strike in a complex system according to any one of claims 1 to 3, wherein said measuring the anisotropic conductivity of composite and metallic mesh comprises:
equivalent metal net is formed into a flat plate layer, conductivity in the length direction and the width direction of the metal net is measured, and equivalent conductivity in the thickness direction of the metal net is calculated by adopting a numerical calculation method;
the conductivity of the composite material in the fiber direction, perpendicular to the fiber direction and in the thickness direction was measured.
8. A lightning direct effect protection optimization and verification device for a complex system, comprising:
the path and characteristic structure determining module is used for determining the overall lightning current conduction path and characteristic structure of a complex system and extracting the characteristic structure to be inspected on the conduction path, wherein the complex system is a complex system comprising a composite material skin and a frame structure;
the integral simplified modeling module is used for carrying out simplified modeling on the integral model of the complex system according to the lightning current conduction path and the simplified modeling principle, and carrying out integral current distribution simulation on the simplified system model;
the fine modeling module is used for carrying out fine modeling on the extracted characteristic structure and obtaining a quantification result of lightning damage simulation of the characteristic structure;
the system comprises a simplified overall modeling module, a lightning path modeling module and a lightning path modeling module, wherein the simplified overall modeling module is used for simplified modeling of the overall system model according to a conduction path and a simplified modeling principle, and establishing a simplified overall lightning path model of a complex object; determining a lightning current conduction model and a lightning current arc striking model of a characteristic structure, wherein the lightning current arc striking model of the characteristic structure is selected by a first lightning zone and a second lightning zone, the lightning current conduction model is built by a third lightning zone and a system internal structure, and the surface of an aircraft in the first lightning zone is most susceptible to lightning strike; the aircraft surface selected for the second lightning zone is most susceptible to sweeping by lightning strikes starting from the first lightning zone; the third lightning zone comprises all aircraft surfaces except the first lightning zone and the second lightning zone, and the third lightning zone is penetrated by the current of the lightning outlet point and the lightning inlet point; carrying out overall current distribution simulation on the simplified system model;
the fine modeling module is used for measuring the anisotropic conductivity of the composite material and the metal net under the condition of obtaining the quantitative result of lightning damage simulation of the characteristic structure; establishing a mesh subdivision principle aiming at model characteristics; setting a physical field and boundary conditions and selecting a transient solver suitable for model solving; lightning damage is quantified by temperature distribution.
9. The complex system lightning direct effect protection optimization and verification device of claim 8, wherein the complex system lightning direct effect protection optimization and verification device is configured to perform operations to implement the complex system lightning direct effect protection optimization and verification method of any one of claims 2-7.
10. A lightning direct effect protection optimization and verification device for a complex system, comprising:
a memory for storing instructions;
a processor for executing the instructions such that the complex system lightning direct effect protection optimization and verification device performs operations implementing the complex system lightning direct effect protection optimization and verification method of any one of claims 1-7.
11. A complex system comprising a complex system lightning direct effect protection optimization and verification device according to any one of claims 8-10.
12. A computer readable storage medium storing computer instructions which when executed by a processor implement the method of lightning direct effect protection optimization and verification of a complex system according to any one of claims 1-7.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103530453A (en) * | 2013-09-30 | 2014-01-22 | 南方电网科学研究院有限责任公司 | Analysis method for locking of extra-high voltage direct current system caused by lightning strike on transmission line |
| CN105158562A (en) * | 2015-10-27 | 2015-12-16 | 上海无线电设备研究所 | Time-frequency domain data processing method for whole machine lightning indirect effect experiments |
| CN106671525A (en) * | 2016-12-27 | 2017-05-17 | 中国航空工业集团公司北京航空材料研究院 | Hybrid modified composite material with high-conductivity and high-toughness structure and preparation method of hybrid modified composite material |
| CN108460225A (en) * | 2018-03-21 | 2018-08-28 | 华北电力大学（保定） | A kind of emulation mode and system of anisotropy sheet metal induction type magnetic acoustic image |
| CN109738489A (en) * | 2018-12-06 | 2019-05-10 | 西安交通大学 | Multiple continuous thunder and lightning flow component acts on lower carbon fibre composite damage measurement method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7525785B2 (en) * | 2006-12-14 | 2009-04-28 | The Boeing Company | Lightning strike protection method and apparatus |
| US8645113B2 (en) * | 2008-07-09 | 2014-02-04 | The Boeing Company | Methods and systems for evaluating a design of an aircraft |
-
2019
- 2019-07-09 CN CN201910614646.1A patent/CN112287572B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103530453A (en) * | 2013-09-30 | 2014-01-22 | 南方电网科学研究院有限责任公司 | Analysis method for locking of extra-high voltage direct current system caused by lightning strike on transmission line |
| CN105158562A (en) * | 2015-10-27 | 2015-12-16 | 上海无线电设备研究所 | Time-frequency domain data processing method for whole machine lightning indirect effect experiments |
| CN106671525A (en) * | 2016-12-27 | 2017-05-17 | 中国航空工业集团公司北京航空材料研究院 | Hybrid modified composite material with high-conductivity and high-toughness structure and preparation method of hybrid modified composite material |
| CN108460225A (en) * | 2018-03-21 | 2018-08-28 | 华北电力大学（保定） | A kind of emulation mode and system of anisotropy sheet metal induction type magnetic acoustic image |
| CN109738489A (en) * | 2018-12-06 | 2019-05-10 | 西安交通大学 | Multiple continuous thunder and lightning flow component acts on lower carbon fibre composite damage measurement method |
Non-Patent Citations (2)
| Title |
|---|
| C919 试飞供电***闪电防护仿真研究;刘琳;《中国优秀硕士学位论文全文数据库-工程科技Ⅱ辑》;20180315(第03期);正文第三、五章，第16-24、37-49页 * |
| 刘琳.C919 试飞供电***闪电防护仿真研究.《中国优秀硕士学位论文全文数据库-工程科技Ⅱ辑》.2018,(第03期),正文第三、五章，第16-24、37-49页. * |
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