Three-dimensional woven composite material lightning stroke damage prediction device and method

Abstract

The invention provides a lightning stroke damage prediction device and method for a three-dimensional woven composite material, and the device is characterized in that the device comprises a key region model construction module which is used for obtaining the parameters of the three-dimensional woven composite material, and constructing a key region model according to the parameters; the non-critical area model construction module is used for constructing a macroscopic uniform model as a non-critical area model according to the three-dimensional woven composite material; the coupling module is used for binding and coupling the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model; the data input module is used for inputting boundary conditions, lightning current loads and thermal radiation conditions; and the lightning stroke calculation module is used for calculating the damage area and the damage depth as the lightning stroke damage result according to the boundary condition, the lightning current load, the thermal radiation condition and the three-dimensional woven composite material plate model. In a word, the device and the method can accurately predict the damage result of the three-dimensional woven composite material after lightning stroke.

Description

Technical Field

[0001] The invention relates to the field of aerospace, and in particular to a device and method for predicting lightning damage of a three-dimensional woven composite material. Background Art

[0002] Compared with traditional laminate composite materials, 3D woven composite materials have the advantages of high specific strength, high specific modulus, fatigue resistance, corrosion resistance, strong designability, etc., due to the introduction of yarns in the thickness direction. At the same time, it also greatly improves the interlayer stress resistance of composite materials. At present, 3D woven composite materials have been gradually applied to aircraft engine blades and have become the best choice for engine blades.

[0003] However, the electrical conductivity of carbon fiber composites is several orders of magnitude lower than that of commonly used metal materials, and they are easily damaged by lightning. In addition, since fan blades are rotating parts, it is impossible to lay a lightning protection layer on the blades like on aircraft, which poses a serious safety hazard. In particular, the latest internationally developed next-generation turbofan engine uses an open composite fan structure, and the probability of fan blades being struck by lightning when the aircraft is running is significantly increased. In addition, lightning safety of carbon fiber composite structural parts is an important airworthiness safety requirement, so it is necessary to conduct lightning damage assessment on three-dimensional woven composites.

[0004] However, existing lightning damage prediction methods are all targeted at composite laminates and are not applicable to three-dimensional woven composites. In other words, existing methods find it difficult to comprehensively evaluate the performance and damage of three-dimensional woven composites under lightning strikes. Summary of the invention

[0005] The present invention is made to solve the above-mentioned problem, and its purpose is to provide a device and method for predicting lightning damage of three-dimensional woven composite materials.

[0006] The present invention provides a three-dimensional woven composite material lightning damage prediction device, which is used to obtain the lightning damage result of the three-dimensional woven composite material, and has the following characteristics, including: a key area model construction module, which is used to obtain the parameters of the three-dimensional woven composite material and construct the key area model according to the parameters; a non-key area model construction module, which is used to construct a macroscopic uniform model according to the three-dimensional woven composite material as the non-key area model; a coupling module, which is used to bind and couple the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model; a data input module, which is used to input boundary conditions, lightning current load and thermal radiation conditions; a lightning strike calculation module, which is used to calculate the damage area and damage depth as the lightning strike damage according to the boundary conditions, lightning current load, thermal radiation conditions and the three-dimensional woven composite material plate model. Results, wherein the lightning calculation module includes: a variable calculation unit, which is used to calculate the electric field strength, potential, current density and temperature of each time step according to the boundary conditions, lightning current load, thermal radiation conditions and three-dimensional woven composite material plate model of each time step; a breakdown judgment unit, which stores the dielectric breakdown strength, and is used to judge whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength according to the potential after each time step. If so, the insulator conductivity and conductor conductivity of the part are increased; a pyrolysis calculation unit, which stores the pyrolysis temperature, and is used to judge whether the temperature of each part obtained in the last time step is greater than the pyrolysis temperature. If so, the part is a part damaged by lightning. A lightning damage unit is used to calculate the damage area and damage depth according to all parts damaged by lightning.

[0007] In the three-dimensional woven composite material lightning damage prediction device provided by the present invention, it can also have the following characteristics: wherein, the key area model construction module includes: an RVE construction unit, which is used to obtain the parameters of the three-dimensional woven composite material at the microscopic scale, and construct an RVE geometric model based on the parameters; a performance parameter measurement unit, which is used to obtain the performance parameters of the three-dimensional woven composite material according to the test standard; a property setting unit, which is used to set material properties and periodic boundary conditions for the RVE geometric model; a performance parameter calculation unit, which stores the electrical conductivity calculation formula and the thermal conductivity calculation formula, and is used to obtain the electrical conductivity data of the RVE geometric model according to the electrical conductivity calculation formula, and obtain the thermal conductivity data of the RVE geometric model according to the thermal conductivity calculation formula; a verification unit, which is used to determine whether the electrical conductivity data and the thermal conductivity data are correct according to the performance parameters. If so, the RVE geometric model is used as the key area model; if not, the property setting unit is executed.

[0008] The three-dimensional woven composite material lightning damage prediction device provided by the present invention may also have the following characteristics: wherein the periodic boundary condition is that the temperature or electric potential of each node on the corresponding two faces, edges, and vertices in the RVE geometric model is equal or parallel.

[0009] The three-dimensional woven composite material lightning damage prediction device provided by the present invention may also have the following features: wherein the conductivity calculation formula is: I = ∑ECD × A, Where I is the current, ECD is the current per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, and are the electric potentials at both ends of the specified calculation direction, L is the length of the specified calculation direction, σ is the conductivity in the specified calculation direction, and the conductivity data includes the conductivity in the longitudinal, latitudinal and thickness directions.

[0010] The three-dimensional woven composite material lightning damage prediction device provided by the present invention may also have the following features: wherein the thermal conductivity calculation formula is: Q = ∑HFL × A, Where Q is the heat flux, HFL is the heat flux per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, L is the length in the specified calculation direction, and T A and T B are the temperatures at both ends of the specified calculation direction, k is the thermal conductivity in the specified calculation direction, and the thermal conductivity data includes the thermal conductivity in the longitudinal, latitudinal and thickness directions.

[0011] In the three-dimensional woven composite material lightning strike damage prediction device provided by the present invention, it can also have the following characteristics: wherein, the three-dimensional woven composite material plate model includes surrounding non-critical areas and a central critical area, the surrounding non-critical areas are non-critical area models, and the central critical area is filled with multiple critical area models.

[0012] The three-dimensional woven composite material lightning damage prediction device provided by the present invention may also have the following features: wherein the calculation expression of current density is: ∫ S J e ·ndS=∫ V r c dV, where S is the area, J e is the surface density vector of the current, n is the surface normal vector, V is the volume, r c is the volume density of the charge, and the calculation expressions of the electric field intensity and electric potential are: Where σ E is the conductivity, φ is the electric potential, E is the electric field strength, and the temperature is calculated as: Q j =ηP ec =ηJ e ·E=ηE·σ E E, Where Q j is the internal energy, η is the energy conversion coefficient, ρ is the density, C pis the specific heat capacity, T is the temperature, t is the time, and k is the thermal conductivity of the material in all directions.

[0013] The three-dimensional woven composite material lightning damage prediction device provided by the present invention may also have the following characteristics: in the breakdown judgment unit, when the potential difference is greater than or equal to the dielectric breakdown strength, the conductivity of the insulator in the corresponding part is increased by 6 orders of magnitude, and the conductivity of the conductor is increased by 3 orders of magnitude.

[0014] The present invention also provides a three-dimensional woven composite material lightning damage prediction method, which is used to obtain the lightning damage result of the three-dimensional woven composite material, and has such characteristics, comprising the following steps: step S1, obtaining the parameters of the three-dimensional woven composite material, and constructing a key area model according to the parameters; step S2, constructing a macroscopic uniform model as a non-critical area model according to the three-dimensional woven composite material; step S3, binding and coupling the key area model and the non-critical area model to obtain a three-dimensional woven composite material plate model; step S4, setting boundary conditions, lightning current load and thermal radiation conditions; step S5, according to the boundary conditions, lightning current load, thermal radiation conditions and the three-dimensional woven composite material plate model, calculating the damage area and damage depth as the lightning damage result, wherein step S5 includes the following sub-steps: step S5-1 , according to the boundary conditions, lightning current load, thermal radiation conditions and three-dimensional woven composite material plate model of each time step, the electric field strength, potential, current density and temperature of the time step are calculated; step S5-2, after each time step, according to the potential, whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength, if so, the insulator conductivity and conductor conductivity of the part are increased; step S5-3, judge whether the iteration is completed, if so, enter step S5-4, if not, the time step is increased by 1, and step S5-1 is executed; step S5-4, judge whether the temperature of each part obtained in the last time step is greater than the pyrolysis temperature, if so, the part is a part damaged by lightning; step S5-5, according to all the parts damaged by lightning, calculate the damage area and damage depth.

[0015] Functions and Effects of the Invention

[0016] According to the three-dimensional woven composite material lightning damage prediction device and method involved in the present invention, on the one hand, the entire three-dimensional woven composite material plate model is divided into a key area model and a non-key area model, and a simulation model that can accurately reflect the characteristics of the three-dimensional woven composite material is constructed while reducing unnecessary computing power; on the other hand, the influence of the lightning strike is evaluated at each time step through the pyrolysis calculation unit, so as to obtain the final accurate damage result of the three-dimensional woven composite material plate model. Therefore, the three-dimensional woven composite material lightning damage prediction device and method of the present invention can accurately predict the damage result of the three-dimensional woven composite material after the lightning strike. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a block diagram of a lightning damage prediction device in an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of a periodic boundary condition of heat conduction in an embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of a process for predicting lightning damage of a three-dimensional woven composite material in an embodiment of the present invention;

[0020] Figure 4 is a schematic diagram of lightning strike calculation in an embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of ultrasonic C-scan results of a real three-dimensional woven composite material after a lightning strike test in an embodiment of the present invention;

[0022] Figure 6 is a schematic diagram of a temperature cloud in the inner direction behind a three-dimensional woven composite material plate model simulating a lightning strike in an embodiment of the present invention;

[0023] Figure 7 is a schematic diagram of ultrasonic B-scan results of a real three-dimensional woven composite material after a lightning strike test in an embodiment of the present invention;

[0024] Figure 8 It is a schematic diagram of the temperature cloud in the thickness direction after simulating a lightning strike by a three-dimensional woven composite material plate model in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the device and method for predicting lightning damage to three-dimensional woven composite materials of the present invention.

[0026] The present embodiment provides a three-dimensional woven composite material lightning damage prediction device, hereinafter referred to as a lightning damage prediction device, which is used to obtain a lightning damage result of a three-dimensional woven composite material.

[0027] Figure 1 4 is a block diagram of a lightning damage prediction device in an embodiment of the present invention.

[0028] like Figure 1 As shown, the lightning damage prediction device 100 includes a key area model building module 10, a non-key area model building module 20, a coupling module 30, a data input module 40, a lightning calculation module 50 and a control module 60 for controlling the operation of the above modules.

[0029] The key area model building module 10 is used to obtain parameters of the three-dimensional woven composite material and build a key area model according to the parameters.

[0030] The critical region model construction module 10 includes an RVE construction unit 101 , a performance parameter measurement unit 102 , a property setting unit 103 , a performance parameter calculation unit 104 and a verification unit 105 .

[0031] The RVE construction unit 101 is used to obtain the parameters of the three-dimensional woven composite material at a microscopic scale and construct an RVE geometric model according to the parameters.

[0032] In this embodiment, the RVE construction unit 101 obtains the parameters of the three-dimensional woven composite material at the microscopic scale through CT scanning, and the parameters include the three-dimensional weaving form of the warp and weft yarns, the yarn width, the yarn thickness and the yarn spacing. Since the three-dimensional woven composite material is composed of many repeated cyclic structures in space under ideal conditions, this structure can be selected as the representative unit of the unit cell, namely RVE. Therefore, in this embodiment, the parameters obtained by the above CT scanning are used to construct an RVE geometric model, which can reflect the microscopic structure of the yarn and the matrix, and the yarn size, three-dimensional weaving form and CT scanning results are consistent.

[0033] The performance parameter measuring unit 102 is used to obtain the performance parameters of the three-dimensional woven composite material according to the test standard.

[0034] The performance parameters in this embodiment include the electrical conductivity, thermal conductivity, specific heat capacity, pyrolysis temperature and breakdown strength of the three-dimensional woven composite material as a whole, the matrix and the yarn. Specifically, the electrical conductivity is obtained by testing according to GB / T 31838.2-2019 using the four-section method; the thermal conductivity of the three-dimensional woven composite material and the resin matrix are both tested according to ISO 22007-2-2015, and the thermal conductivity of the yarn is tested according to ASTM D5470-06; the specific heat capacity is tested according to GB / T19466.4-2016; the pyrolysis temperature is tested according to GB / T 33047.1-2016; and the breakdown strength is tested according to GB / T 1408.1-2006.

[0035] The property setting unit 103 is used to set material properties and periodic boundary conditions for the RVE geometric model.

[0036] The periodic boundary condition is that the temperature or potential of each node on the corresponding two faces, edges, and vertices in the RVE geometric model is equal or parallel. In this embodiment, the periodic boundary condition is used to make the calculation results of the electrical and thermal conductivity of the RVE geometric model equivalent to the macroscopic electrical and thermal conductivity of the entire material.

[0037] Figure 2Schematic diagram of the periodic boundary conditions of heat conduction in an embodiment of the present invention.

[0038] like Figure 2 As shown, point B is the constraint point in the x direction, point A' is the constraint point in the y direction, and point D is the constraint point in the z direction. The periodic boundary conditions for heat conduction are as follows:

[0039] 1. Surface:

[0040] T ξ' -T ξ -T D =0,

[0041] T η' -T η -T B =0,

[0042] T ζ' -T ζ -T A' =0,

[0043] Where T ξ is the temperature of any point on the surface, T ξ' is the temperature of the corresponding point on the surface ξ′; T D is the temperature of point D; T η is the temperature of any point on the surface η, T η' is the temperature of the corresponding point on the surface η′; T B is the temperature of point B; T ζ is the temperature of any point on the surface, T ζ' is the temperature of the corresponding point on the surface ζ′; T A' is the temperature of point A'.

[0044] 2. Edge:

[0045] T C'D' -T CD -T A' =0,

[0046] T C'D' -T A'B' -T D =0,

[0047] T A'B' -T AB -T A' =0,

[0048] T C'C -T DD' -T B =0,

[0049] T C'C -T BB' -TD =0,

[0050] T BB' -T AA' -T B =0,

[0051] T BC -T AD -T B =0,

[0052] T B'C' -T BC -T A' =0,

[0053] T B'C' -T A'D' -T B =0,

[0054] Where T CD is the temperature of any point on edge CD, T C'D' is the temperature of the corresponding point on edge C'D'; T AB is the temperature of any point on edge AB, T A'B' is the temperature of the corresponding point on edge A'B'; T C'C is the temperature of any point on edge C'C, T DD' is the temperature of the corresponding point on edge DD'; T BB' is the temperature of any point on edge BB', T AA' is the temperature of the corresponding point on edge AA'; T BC is the temperature of any point on edge BC, T AD is the temperature of the corresponding point on edge AD; T B'C' is the temperature of any point on edge B'C', T A'D' is the temperature of the corresponding point on edge A'D'.

[0055] 3. Vertex:

[0056] T C -T D -T B =0,

[0057] T D -T D' -T A' =0,

[0058] T B' -T A' -T B =0,

[0059] T C' -T C -T A' =0,

[0060] Where T C is the temperature of point C, T D' is the temperature of point D', T B' is the temperature of point B', T C' is the temperature of point C'.

[0061] The performance parameter calculation unit 104 stores an electrical conductivity calculation formula and a thermal conductivity calculation formula, and is used to obtain electrical conductivity data of the RVE geometric model according to the electrical conductivity calculation formula, and to obtain thermal conductivity data of the RVE geometric model according to the thermal conductivity calculation formula.

[0062] The conductivity data includes the conductivity in the warp, weft and thickness directions. The conductivity calculation formula is:

[0063] I=∑ECD×A,

[0064]

[0065]

[0066] Where I is the current, ECD is the current per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, and are the electric potentials at both ends of the specified calculation direction, L is the length of the specified calculation direction, and σ is the conductivity in the specified calculation direction.

[0067] In this embodiment, a certain potential difference is set at both ends of the specified calculation direction of the RVE geometric model, so as to obtain the total current passing through the specified calculation direction, and then obtain the conductivity of the specified calculation direction through the above conductivity calculation formula.

[0068] The thermal conductivity data includes the thermal conductivity in the warp, weft and thickness directions. The thermal conductivity calculation formula is:

[0069] Q=∑HFL×A,

[0070]

[0071] Where Q is the heat flux, HFL is the heat flux per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, L is the length in the specified calculation direction, and T A and T B are the temperatures at both ends of the specified calculation direction, and k is the thermal conductivity in the specified calculation direction.

[0072] In this embodiment, a certain temperature difference is set at both ends of the specified calculation direction of the RVE geometric model to obtain the heat flow through the specified calculation direction, and then the thermal conductivity of the specified calculation direction is obtained through the above thermal conductivity calculation formula.

[0073] The verification unit 105 is used to determine whether the electrical conductivity data and the thermal conductivity data are correct according to the performance parameters. If so, the RVE geometric model is used as the key area model. If not, the property setting unit 103 is executed. That is, when the verification result of the RVE geometric model is incorrect, the corresponding parameters and conditions are readjusted by the property setting unit 103, and the adjusted RVE geometric model is subsequently verified again, and this is repeated until the verification result is correct, and the corresponding RVE geometric model is used as the key area model.

[0074] The non-critical region model building module 20 is used to build a macroscopic uniform model as a non-critical region model according to the three-dimensional woven composite material.

[0075] In this embodiment, the material properties of the non-critical region model are set according to the overall macroscopic material properties of the three-dimensional woven composite material, including thermal conductivity, electrical conductivity, specific heat capacity, pyrolysis temperature and breakdown strength.

[0076] The coupling module 30 is used to bind and couple the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model.

[0077] Among them, the three-dimensional woven composite material plate model includes surrounding non-critical areas and a central critical area. The surrounding non-critical areas are non-critical area models, and the central critical area is filled with multiple critical area models.

[0078] The data input module 40 is used to input boundary conditions, lightning current loads and heat radiation conditions.

[0079] In this embodiment, the boundary condition is that the four sides or one side is grounded, and its potential is defined as 0. The lightning current load is applied according to the standard "SAEARP5416" A wave, B wave, C wave, D wave or combined wave. The thermal radiation condition is to define the three-dimensional woven composite plate model as surface thermal radiation to achieve heat flow radiation transfer between the material and the environment.

[0080] The lightning strike calculation module 50 is used to calculate the damage area and damage depth as the lightning strike damage result according to the boundary conditions, lightning current load, thermal radiation conditions and the three-dimensional woven composite material plate model.

[0081] The lightning strike calculation module 50 includes a variable calculation unit 501 , a breakdown determination unit 502 , a thermal decomposition calculation unit 503 and a lightning strike damage unit 504 .

[0082] The variable calculation unit 501 is used to calculate the electric field intensity, electric potential, current density and temperature of each time step according to the boundary conditions, lightning current load, thermal radiation conditions and the three-dimensional woven composite material plate model of the time step.

[0083] The calculation expression of current density is:

[0084] ∫ S J e ·ndS=∫ V r c dV,

[0085] Where S is the area, J e is the surface density vector of the current, n is the surface normal vector, V is the volume, r c is the volume density of charge.

[0086] The calculation expressions of electric field strength and electric potential are:

[0087]

[0088] Where σ E is the conductivity, φ is the electric potential, and E is the electric field strength.

[0089] The calculation expression of temperature is:

[0090] Q j =ηP ec =ηJ e ·E=ηE·σ E E,

[0091]

[0092] Where Q j is the internal energy, η is the energy conversion coefficient, ρ is the density, C p is the specific heat capacity, T is the temperature, t is the time, and k is the thermal conductivity of the material in all directions.

[0093] The breakdown determination unit 502 stores the dielectric breakdown strength and is used to determine whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength according to the electric potential after each time step. If so, the insulator conductivity and conductor conductivity of the part are increased.

[0094] Wherein, in the breakdown determination unit 502, when the potential difference is greater than or equal to the dielectric breakdown strength, the conductivity of the insulator at the corresponding position is increased by 6 orders of magnitude, and the conductivity of the conductor is increased by 3 orders of magnitude.

[0095] The pyrolysis calculation unit 503 stores the pyrolysis temperature, which is used to determine whether the temperature of each part obtained in the last time step is greater than the pyrolysis temperature. If so, the part is damaged by lightning. Since the damage caused by lightning is mainly burning damage, the lightning damage at each time step can be described by the pyrolysis situation.

[0096] The lightning damage unit 504 is used to calculate the damage area and damage depth based on all the parts damaged by lightning.

[0097] The control module 60 stores a control program for controlling the operation of each module.

[0098] The following describes the process of using the lightning damage prediction device 100 to predict lightning damage of a three-dimensional woven composite material in conjunction with the accompanying drawings.

[0099] Figure 3 It is a schematic diagram of the process of predicting lightning damage of three-dimensional woven composite materials in an embodiment of the present invention.

[0100] like Figure 3 As shown in the figure, the lightning damage prediction of 3D woven composites includes the following steps:

[0101] Step S1, using the key area model building module 10 to obtain parameters of the three-dimensional woven composite material, and building a key area model according to the parameters.

[0102] Step S2: using the non-critical region model building module 20 to build a macroscopic uniform model according to the three-dimensional woven composite material as the non-critical region model.

[0103] Step S3, using the coupling module 30 to bind and couple the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model.

[0104] Step S4: using the data input module 40 to input boundary conditions, lightning current load and heat radiation conditions.

[0105] Step S5, using the lightning strike calculation module 50 to calculate the damage area and damage depth as the lightning strike damage result according to the boundary conditions, lightning current load, thermal radiation conditions and the three-dimensional woven composite material plate model.

[0106] Wherein, step S5 includes the following sub-steps:

[0107] Step S5-1, using the variable calculation unit 501 to calculate the electric field strength, potential, current density and temperature of each time step according to the boundary conditions, lightning current load, thermal radiation conditions and three-dimensional woven composite material plate model of each time step. In this embodiment, the variable calculation unit 501 calculates the boundary conditions, lightning current load, thermal radiation conditions and three-dimensional woven composite material plate model of the current time step in each iterative time step, and then obtains the electric field strength, potential, current density and temperature of the current time step.

[0108] Step S5-2, using the breakdown determination unit 502 to determine whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength according to the potential after each time step, if so, the insulator conductivity and conductor conductivity of the part are increased.

[0109] Step S5-3, determine whether the iteration is completed, if so, enter step S5-4, if not, the time step is increased by 1 and step S5-1 is executed.

[0110] Step S5-4, using the pyrolysis calculation unit 503 to determine whether the temperature of each part obtained in the last time step is greater than the pyrolysis temperature, if so, the part is a part damaged by lightning.

[0111] Step S5-5: The lightning damage unit 504 is used to calculate the damage area and damage depth based on all the parts damaged by lightning.

[0112] In this embodiment, step S1 is performed first and then step S2. In other embodiments, the order of step S1 and step S2 can be swapped according to actual needs, that is, step S2 is performed first and then step S1, or step S1 and step S2 are performed simultaneously.

[0113] In this embodiment, the lightning damage prediction device 100 is used to predict the lightning damage of the existing three-dimensional woven composite material. The specific details are as follows:

[0114] The RVE geometric model corresponding to the three-dimensional woven composite material with a size of 12.07mm*6.1mm*5.72mm, 8 layers of weft yarns and 7 layers of warp yarns is constructed by using the modeling software Texgen through the key area model construction module 10. The microscopic structure of the yarn and the matrix is ​​established in the RVE geometric model, specifically: the width of the warp yarn is 1.431mm, the thickness is 0.487mm, and the spacing is 1.431mm; the width of the weft yarn is 2.414mm, the thickness is 0.284mm, and the spacing is 3.017mm.

[0115] The performance parameter calculation unit 104 is used to set the potential difference at both ends of the specified calculation direction when calculating the electrical conductivity to 9V, and to set the temperature difference at both ends of the specified calculation direction when calculating the thermal conductivity to 100°C.

[0116] The coupling module 30 is used to establish a space with a non-critical area of ​​200mm*200mm on all sides and a 50mm*50mm space dug out in the middle, and the central critical area is a 50mm*50mm space dug out, and then the non-critical area model and the critical area model are combined to generate a three-dimensional woven composite material plate model.

[0117] The boundary conditions inputted by the data input module 40 are that the ground is all around, and its potential is defined as 0; the lightning current load is a D wave with an amplitude of 100 kA and a duration of 3.3 μs; and the surface thermal radiation is 0.9.

[0118] Figure 4 Schematic diagram of lightning strike calculation in an embodiment of the present invention.

[0119] like Figure 4 As shown, in this embodiment, the central key area, i.e., the microscopic area, is simulated by lightning strike, so as to obtain the lightning strike damage result of the three-dimensional woven composite material. In addition, the macroscopic area is the surrounding non-critical area, the Weft is the weft yarn, the Warp is the warp yarn, the Side Surfaces is the boundary surface, and the Atmosphere 25℃ indicates the ambient temperature of 25℃.

[0120] Figure 5 It is a schematic diagram of ultrasonic C-scan results of a real three-dimensional woven composite material after a lightning strike test in an embodiment of the present invention.

[0121] like Figure 5 As shown in the figure, the left figure is a schematic diagram of the ultrasonic C-scan results of the real three-dimensional woven composite material after the lightning strike test, and the right figure is a schematic diagram of the left figure after partial enlargement. The surface morphology of the damaged area can be seen from the right figure, and the damaged area is 370.728mm 2 .

[0122] Figure 6 It is a schematic diagram of the temperature cloud in the inner direction behind the three-dimensional woven composite material plate model simulating a lightning strike in an embodiment of the present invention.

[0123] like Figure 6 As shown, (a) is the overall schematic diagram of the damaged area, (b) is the schematic diagram after the damage area is enlarged, and (c) is a schematic diagram of the damage perspective based on Figure (b). According to the calculation, the simulated damage area is 407.703mm 2 , and the error with the true test is 9.9%.

[0124] Figure 7 It is a schematic diagram of ultrasonic B-scan results of a real three-dimensional woven composite material after a lightning strike test in an embodiment of the present invention.

[0125] like Figure 7 As shown, the left picture is a schematic diagram of the B-scan position, and the right picture is the B-scan result, which shows that the damage depth is 3.64mm.

[0126] Figure 8 It is a schematic diagram of the temperature cloud in the thickness direction after simulating a lightning strike by a three-dimensional woven composite material plate model in an embodiment of the present invention.

[0127] like Figure 8As shown, according to the temperature cloud map, it can be calculated that the simulated damage depth is 3.01 mm, and the error with the actual test is 17.3%.

[0128] It can be seen that the lightning damage prediction device 100 of this embodiment can more accurately simulate the damage results of three-dimensional woven composite materials after lightning strike, which is conducive to the prediction and evaluation of lightning damage to aircraft engine blades made of three-dimensional woven composite materials.

[0129] Functions and Effects of the Embodiments

[0130] According to the device and method for predicting lightning damage of three-dimensional woven composite materials involved in this embodiment, on the one hand, the entire three-dimensional woven composite material plate model is divided into a key area model and a non-key area model, and a simulation model that can accurately reflect the characteristics of the three-dimensional woven composite material is constructed while reducing unnecessary computing power; on the other hand, the influence of lightning strike is evaluated at each time step through the pyrolysis calculation unit, so as to obtain the final accurate damage result of the three-dimensional woven composite material plate model. In short, the device and method can accurately predict the damage result of three-dimensional woven composite materials after lightning strike.

[0131] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A three-dimensional woven composite material lightning damage prediction device, used to obtain the lightning damage result of the three-dimensional woven composite material, characterized in that: include: A key area model building module, used to obtain parameters of the three-dimensional woven composite material and build a key area model according to the parameters; A non-critical area model building module, used to build a macroscopic uniform model as a non-critical area model according to the three-dimensional woven composite material; A coupling module, used for binding and coupling the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model; Data input module, used to input boundary conditions, lightning current loads and thermal radiation conditions; a lightning strike calculation module, for calculating the damage area and the damage depth as the lightning strike damage result according to the boundary conditions, the lightning current load, the heat radiation conditions and the three-dimensional woven composite material plate model; Wherein, the lightning strike calculation module includes: A variable calculation unit, used for calculating the electric field intensity, electric potential, current density and temperature of each time step according to the boundary conditions, the lightning current load, the thermal radiation conditions and the three-dimensional woven composite material plate model of the time step; A breakdown determination unit, storing the dielectric breakdown strength, is used to determine whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength according to the potential after each time step, and if so, increase the insulator conductivity and conductor conductivity of the part; A pyrolysis calculation unit stores the pyrolysis temperature and is used to determine whether the temperature of each of the parts obtained in the last time step is greater than the pyrolysis temperature. If so, the part is a part damaged by lightning. The lightning damage unit is used to calculate the damage area and the damage depth according to all the parts damaged by lightning.

2. The three-dimensional woven composite material lightning damage prediction device according to claim 1, Features: in, The key area model building module includes: An RVE construction unit, used for obtaining parameters of the three-dimensional woven composite material at a microscopic scale, and constructing an RVE geometric model according to the parameters; A performance parameter measuring unit, used to obtain the performance parameters of the three-dimensional woven composite material according to the test standard; A property setting unit, used for setting material properties and periodic boundary conditions for the RVE geometric model; a performance parameter calculation unit storing an electrical conductivity calculation formula and a thermal conductivity calculation formula, for obtaining electrical conductivity data of the RVE geometric model according to the electrical conductivity calculation formula, and obtaining thermal conductivity data of the RVE geometric model according to the thermal conductivity calculation formula; A verification unit is used to determine whether the electrical conductivity data and the thermal conductivity data are correct according to the performance parameters. If so, the RVE geometric model is used as the key area model; if not, the property setting unit is executed.

3. The three-dimensional woven composite material lightning damage prediction device according to claim 2, characterized in that: in, The periodic boundary condition is that the temperature or electric potential of each node on the corresponding two faces, edges, and vertices in the RVE geometric model is equal or parallel.

4. The three-dimensional woven composite material lightning damage prediction device according to claim 2, characterized in that: in, The conductivity calculation formula is: I=∑ECD×A, Where I is the current, ECD is the current per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, and are the electric potentials at both ends of the specified calculation direction, L is the length of the specified calculation direction, σ is the conductivity in the specified calculation direction, The electrical conductivity data includes electrical conductivity in the warp direction, the weft direction and the thickness direction.

5. The three-dimensional woven composite material lightning damage prediction device according to claim 2, characterized in that: in, The thermal conductivity calculation formula is: Q=∑HFL×A, Where Q is the heat flux, HFL is the heat flux per unit area of ​​each unit obtained by finite element calculation, A is the cross-sectional area in the specified calculation direction, L is the length in the specified calculation direction, and T A and T B are the temperatures at both ends of the specified calculation direction, k is the thermal conductivity in the specified calculation direction, The thermal conductivity data include thermal conductivity in the warp direction, the weft direction and the thickness direction.

6. The three-dimensional woven composite material lightning damage prediction device according to claim 1, characterized in that: in, The three-dimensional woven composite material plate model includes surrounding non-critical areas and a central critical area. The surrounding non-critical areas are the non-critical area model. The central key area is filled with a plurality of key area models.

7. The three-dimensional woven composite material lightning damage prediction device according to claim 1, characterized in that: in, The calculation expression of the current density is: ∫ S J e ·ndS=∫ V r c dV, Where S is the area, J e is the surface density vector of the current, n is the surface normal vector, V is the volume, r c is the volume density of charge, The calculation expressions of the electric field intensity and the electric potential are: Where σ E is the conductivity, φ is the electric potential, E is the electric field strength, The calculation expression of the temperature is: Q j =ηP ec =ηJ e ·E=ηE·σ E ·E, Where Q j is the internal energy, η is the energy conversion coefficient, ρ is the density, C p is the specific heat capacity, T is the temperature, t is the time, and k is the thermal conductivity of the material in all directions.

8. The three-dimensional woven composite material lightning damage prediction device according to claim 1, characterized in that: in, In the breakdown determination unit, when the potential difference is greater than or equal to the dielectric breakdown strength, the conductivity of the insulator at the corresponding portion is increased by 6 orders of magnitude, and the conductivity of the conductor is increased by 3 orders of magnitude.

9. A method for predicting lightning damage of a three-dimensional woven composite material, used to obtain lightning damage results of a three-dimensional woven composite material, characterized in that: The following steps are involved: Step S1, obtaining parameters of the three-dimensional woven composite material, and constructing a key area model according to the parameters; Step S2, constructing a macroscopic uniform model as a non-critical area model according to the three-dimensional woven composite material; Step S3, binding and coupling the key area model and the non-key area model to obtain a three-dimensional woven composite material plate model; Step S4, setting boundary conditions, lightning current load and heat radiation conditions; Step S5, calculating the damage area and damage depth as the lightning damage result according to the boundary condition, the lightning current load, the heat radiation condition and the three-dimensional woven composite material plate model, Wherein, the step S5 includes the following sub-steps: Step S5-1, calculating the electric field intensity, electric potential, current density and temperature of each time step according to the boundary conditions, the lightning current load, the thermal radiation conditions and the three-dimensional woven composite material plate model of the time step; Step S5-2, after each time step, judging whether the potential difference of each part of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength according to the potential, and if so, increasing the insulator conductivity and the conductor conductivity of the part; Step S5-3, determine whether the iteration is completed, if so, proceed to step S5-4, if not, add 1 to the time step and execute step S5-1; Step S5-4, determining whether the temperature of each of the parts obtained in the last time step is greater than the pyrolysis temperature, if so, the part is a part damaged by lightning; Step S5-5, calculating the damage area and the damage depth based on all the parts damaged by lightning.

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