Three-dimensional woven composite lightning strike damage prediction apparatus and method

Abstract

The application provides a lightning stroke damage prediction device and method for three-dimensional woven composite materials, which has the characteristics that the device comprises a key area model construction module, which is used for acquiring parameters of the three-dimensional woven composite material and constructing a key area model according to the parameters; a non-key area model construction module, which is used for constructing a macroscopic uniform model as a non-key area model according to the three-dimensional woven composite material; a coupling module, which 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; a data input module, which is used for inputting boundary conditions, lightning current load and thermal radiation conditions; and a lightning stroke calculation module, which is used for calculating damage area and damage depth as lightning stroke damage results according to the boundary conditions, the lightning current load, the thermal radiation conditions and the three-dimensional woven composite material plate model. In summary, the device and the method can accurately predict the damage results of the three-dimensional woven composite material after lightning stroke.

Description

Technical Field

[0001] The present 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 to traditional laminated composites, 3D woven composites, due to the introduction of yarns through the thickness, offer advantages such as high specific strength, high specific modulus, fatigue resistance, corrosion resistance, and strong designability, while also significantly improving the interlaminar stress resistance of the composite. Currently, 3D woven composites are gradually being used in aircraft engine blades, becoming the optimal choice for engine blades.

[0003] However, carbon fiber composites have electrical conductivity several orders of magnitude lower than common metal materials, making them susceptible to damage from lightning. Furthermore, since fan blades are rotating components, they cannot be protected with lightning protection layers like on aircraft, posing a serious safety hazard. In particular, the latest internationally developed next-generation turbofan engines utilize open composite fan structures, significantly increasing the probability of fan blades being struck by lightning during aircraft operation. Furthermore, lightning strike safety of carbon fiber composite structural components is a key airworthiness safety requirement, necessitating lightning damage assessments for 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 problems, and its purpose is to provide a device and method for predicting lightning damage of three-dimensional woven composite materials.

[0006] The application provides a lightning damage prediction device for three-dimensional woven composite materials, which is used for obtaining lightning damage results of three-dimensional woven composite materials and has the following characteristics: a key area model construction module, which is used for obtaining parameters of the three-dimensional woven composite materials and constructing a key area model according to the parameters; a non-key area model construction module, which is used for constructing a macroscopic uniform model as a non-key area model according to the three-dimensional woven composite materials; a coupling module, which 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; a data input module, which is used for inputting boundary conditions, lightning current load and thermal radiation conditions; a lightning calculation module, which is used for calculating damage area and damage depth as lightning damage results according to the boundary conditions, the lightning current load, the thermal radiation conditions and the three-dimensional woven composite material plate model, wherein the lightning calculation module comprises: a variable calculation unit, which is used for calculating electric field intensity, electric potential, current density and temperature at 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; a breakdown judgment unit, which stores dielectric breakdown strength and is used for 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 electric potential after each time step, and if yes, the insulation conductivity and the conductor conductivity of the part are increased; a pyrolysis calculation unit, which stores pyrolysis temperature and is used for judging whether the temperature of each part obtained at the last time step is greater than the pyrolysis temperature, and if yes, the part is a lightning damaged part; and a lightning damage unit, which is used for calculating the damage area and the damage depth according to all the lightning damaged parts.

[0007] In the lightning damage prediction device for three-dimensional woven composite materials provided by the application, the key area model construction module can further have the following characteristics: an RVE construction unit, which is used for obtaining parameters of the three-dimensional woven composite materials at a mesoscale and constructing an RVE geometric model according to the parameters; a performance parameter measurement unit, which is used for obtaining performance parameters of the three-dimensional woven composite materials according to a test standard; an attribute setting unit, which is used for setting material attributes and periodic boundary conditions for the RVE geometric model; a performance parameter calculation unit, which stores an electrical conductivity calculation formula and a thermal conductivity calculation formula and is used 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; and a verification unit, which is used for judging whether the electrical conductivity data and the thermal conductivity data are correct according to the performance parameters, and if yes, the RVE geometric model is taken as the key area model, and if not, the attribute setting unit is executed.

[0008] In the lightning damage prediction device for three-dimensional woven composite materials provided by the application, the periodic boundary conditions can be that the temperatures or electric potentials of nodes on two faces, edges or vertices in the RVE geometric model are equal or parallel.

[0009] In the three-dimensional woven composite lightning strike damage prediction device provided by the application, the conductivity calculation formula can be: I = ∑ECD×A, wherein I is the current, ECD is the current per unit area of each unit calculated by the finite element method, A is the cross-sectional area of the specified calculation direction, and and L is the length of the specified calculation direction, σ is the conductivity of the specified calculation direction, and the conductivity data includes the conductivity in the warp direction, the weft direction and the thickness direction.

[0010] In the three-dimensional woven composite lightning strike damage prediction device provided by the application, the thermal conductivity calculation formula can be: Q = ∑HFL×A, wherein Q is the heat flow, HFL is the heat flow per unit area of each unit calculated by the finite element method, A is the cross-sectional area of the specified calculation direction, L is the length of the specified calculation direction, T A and T B are the temperatures at both ends of the specified calculation direction, and k is the thermal conductivity of the specified calculation direction, and the thermal conductivity data includes the thermal conductivity in the warp direction, the weft direction and the thickness direction.

[0011] In the three-dimensional woven composite lightning strike damage prediction device provided by the application, the three-dimensional woven composite plate model can include a peripheral non-critical area and a central critical area, the peripheral non-critical area is a non-critical area model, and the central critical area is composed of a plurality of critical area models.

[0012] In the three-dimensional woven composite lightning strike damage prediction device provided by the application, the calculation expression of the current density can be: ∫ S J e ·ndS = ∫ V r c dV, wherein 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 the potential are: wherein σ E is the conductivity, φ is the potential, and E is the electric field intensity, and the calculation expression of the temperature is: Q j = ηP ec = ηJ e ·E = ηE·σ E ·E, wherein 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: wherein, 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 for obtaining a lightning damage result of a three-dimensional woven composite material, which has the following characteristics, including the following steps: 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 according to the three-dimensional woven composite material as a non-critical area model; 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, add 1 to the time step and execute step S5-1; 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, calculate the damage area and damage depth based on all parts damaged by lightning.

[0015] Functions and effects of the invention

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

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

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

[0019] Figure 3 1 is a schematic diagram of a process for predicting lightning damage to a three-dimensional woven composite material according to 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 Schematic diagram of a temperature cloud in the inner direction behind a lightning strike simulated by a three-dimensional woven composite material plate model according to 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 Schematic diagram of the temperature cloud in the thickness direction after a three-dimensional woven composite material plate model simulates a lightning strike 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 easier to understand, the following embodiments and accompanying drawings specifically illustrate the device and method for predicting lightning damage to three-dimensional woven composite materials of the present invention.

[0026] This embodiment provides a three-dimensional woven composite material lightning damage prediction device, hereinafter referred to as the lightning damage prediction device, which is used to obtain lightning damage results of the 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 construction module 10, a non-key area model construction 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 key region model construction module 10 includes an RVE construction unit 101 , a performance parameter measurement unit 102 , an attribute setting unit 103 , a performance parameter calculation unit 104 and a verification unit 105 .

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

[0032] In this embodiment, the RVE construction unit 101 obtains microscopic parameters of the three-dimensional woven composite material through CT scanning. These parameters include the three-dimensional weave pattern of the warp and weft yarns, yarn width, yarn thickness, and yarn spacing. Ideally, a three-dimensional woven composite material is spatially composed of many repeating, cyclic structures, so this structure can be selected as a representative unit cell, namely, the RVE. Therefore, in this embodiment, the parameters obtained through the CT scan are used to construct an RVE geometric model. This RVE geometric model can reflect the microscopic structure of the yarn and matrix, and the yarn size, three-dimensional weave pattern, and CT scan 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 measured in accordance with GB / T 31838.2-2019 using the four-section method; the thermal conductivity of the three-dimensional woven composite material and the resin matrix is ​​measured in accordance with ISO 22007-2-2015, and the thermal conductivity of the yarn is measured in accordance with ASTM D5470-06; the specific heat capacity is measured in accordance with GB / T 19466.4-2016; the pyrolysis temperature is measured in accordance with GB / T 33047.1-2016; and the breakdown strength is measured in accordance with 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 requires that the temperatures or potentials of nodes on two corresponding faces, edges, or vertices in the RVE geometric model be equal or parallel. In this embodiment, the periodic boundary condition is used to ensure that the electrical and thermal conductivity calculation results of the RVE geometric model can effectively reflect 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 at point C, T D' is the temperature at point D', T B' is the temperature at point B', T C' is the temperature at point C'.

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

[0062] The electrical conductivity data includes electrical conductivity in the warp direction, the weft direction and the thickness direction, and the electrical 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 element calculated by the finite element method, A is the cross-sectional area in the specified calculation direction, and are the potentials at the two ends of the specified calculation direction, L is the length of the specified calculation direction, and σ is the electrical conductivity in the specified calculation direction.

[0067] In this embodiment, a certain potential difference is set between the two 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 the electrical conductivity in the specified calculation direction is obtained by the above electrical conductivity calculation formula.

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

[0069] Q =∑HFL×A,

[0070]

[0071] where Q is the heat flow, HFL is the heat flow per unit area of each element calculated by the finite element method, A is the cross-sectional area in the specified calculation direction, L is the length of the specified calculation direction, T A and T B are the temperatures at the two 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 between the two ends of the specified calculation direction of the RVE geometric model, so as to obtain the heat flow passing through the specified calculation direction, and then the thermal conductivity in the specified calculation direction is obtained by the above thermal conductivity calculation formula.

[0073] The verification unit 105 is configured to determine whether the conductivity data and the thermal conductivity data are correct according to the performance parameters, if yes, the RVE geometric model is taken as the key region model, if not, the attribute setting unit 103 is executed. That is, when the verification result of the RVE geometric model is incorrect, the corresponding parameters and conditions are re-adjusted through the attribute setting unit 103, and the adjusted RVE geometric model is verified again in the subsequent, and so on until the verification result is correct, and then the corresponding RVE geometric model is taken as the key region model.

[0074] The non-key region model construction module 20 is configured to construct a macroscopic uniform model as the non-key region model according to the three-dimensional woven composite material.

[0075] In the embodiment, the material properties of the non-key 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 configured to bind and couple the key region model and the non-key region model to obtain a three-dimensional woven composite material plate model.

[0077] The three-dimensional woven composite material plate model includes a peripheral non-key region and a central key region, the peripheral non-key region is the non-key region model, and the central key region is filled with a plurality of key region models.

[0078] The data input module 40 is configured to input boundary conditions, lightning current load and thermal radiation conditions.

[0079] In the embodiment, the boundary condition is that the periphery or one side is grounded, and the electric potential thereof is defined as 0. The lightning current load is applied according to the standard “SAEARP5416” to apply A wave, B wave, C wave, D wave or combined wave. The thermal radiation condition is that the three-dimensional woven composite material plate model is defined as surface thermal radiation to realize heat flow radiation transfer between the material and the environment.

[0080] The lightning strike calculation module 50 is configured to calculate the damage area and the damage depth as the lightning strike damage result according to the boundary conditions, the lightning current load, the 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 judgment unit 502, a pyrolysis calculation unit 503 and a lightning strike damage unit 504.

[0082] The variable calculation unit 501 is configured to calculate the electric field strength, the electric potential, the current density and the 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.

[0083] wherein the calculation expression of the current density is:

[0084] ∫ S J e ·ndS=∫ V r c dV,

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

[0086] The calculation expression of the electric field intensity and the electric potential is:

[0087]

[0088] wherein σ E is the conductivity, φ is the electric potential, and E is the electric field intensity.

[0089] The calculation expression of the temperature is:

[0090] Q j =ηP ec =ηJ e ·E=ηE·σ E ·E,

[0091]

[0092] wherein 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 each direction.

[0093] The breakdown determination unit 502 stores the dielectric breakdown strength, and is configured 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, and if so, increase the insulator conductivity and the conductor conductivity of the part.

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

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

[0096] The lightning damage unit 504 is used to calculate the damage area and damage depth based on all 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 to a three-dimensional woven composite material with reference to the accompanying drawings.

[0099] Figure 3 It is a schematic flow chart of lightning damage prediction for three-dimensional woven composite materials in an embodiment of the present invention.

[0100] like Figure 3 As shown in Figure 2, the lightning damage prediction of 3D woven composites includes the following steps:

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

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

[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] In step S5 , 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.

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

[0107] In step S5-1, the variable calculation unit 501 calculates the electric field intensity, potential, current density, and temperature for each time step based on the boundary conditions, lightning current load, thermal radiation conditions, and the three-dimensional woven composite material panel model. In this embodiment, the variable calculation unit 501 calculates the boundary conditions, lightning current load, thermal radiation conditions, and the three-dimensional woven composite material panel model for each iterative time step to obtain the electric field intensity, potential, current density, and temperature for the current time step.

[0108] Step S5-2, the breakdown determination unit 502 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, the insulator conductivity and the conductor conductivity of the part are increased.

[0109] Step S5-3, it is determined whether the iteration is ended, if so, step S5-4 is entered, if not, the time step is added by 1, and step S5-1 is executed.

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

[0111] Step S5-5, the lightning damage unit 504 is used to calculate the damage area and the damage depth according to all lightning damaged parts.

[0112] In this embodiment, step S1 is performed first and then step S2 is performed. In other embodiments, the order of steps S1 and S2 can be changed according to actual needs, that is, step S2 is performed first and then step S1 is performed, or steps S1 and 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, and the specific details are as follows:

[0114] The key area model construction module 10 uses the modeling software Texgen to construct 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 yarn and 7 layers of warp yarn. And the microstructure of the yarn and the matrix is established in the RVE geometric model, specifically: the warp yarn width is 1.431mm, the thickness is 0.487mm, and the spacing is 1.431mm; the weft yarn width is 2.414mm, the thickness is 0.284mm, and the spacing is 3.017mm.

[0115] The performance parameter calculation unit 104 sets the potential difference between the two ends of the specified calculation direction when calculating the conductivity to be 9V, and sets the temperature difference between the two ends of the specified calculation direction when calculating the thermal conductivity to be 100℃.

[0116] The coupling module 30 is used to establish a non-key area of 200mm*200mm around and a center key area of a space of 50mm*50mm, and then generate a three-dimensional woven composite material plate model by combining the non-key area model and the key area model.

[0117] The boundary condition input by the data input module 40 is four-side grounding, and the 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 is a schematic diagram of lightning calculation in an embodiment of the present application.

[0119] As shown in Figure 4 , in this embodiment, the central key area, i.e., the mesoscopic area, is simulated for lightning, so as to obtain the lightning damage result of the three-dimensional woven composite material. In addition, the macroscopic is a non-key area around, Weft is weft yarn, Warp is warp yarn, Side Surfaces is boundary surface, and Atmosphere 25℃ represents an environment temperature of 25℃.

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

[0121] As shown in Figure 5 , the left side diagram is a schematic diagram of the ultrasonic C scan result of the real three-dimensional woven composite material after lightning test, and the right side diagram is a schematic diagram of the left side diagram after local amplification. As shown in the right side diagram, the surface morphology of the damage area can be seen, and then the damage area is 370.728 mm 2 .

[0122] Figure 6 is a schematic diagram of the temperature cloud in the face inner direction of the three-dimensional woven composite material plate model after lightning simulation in an embodiment of the present application.

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

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

[0125] As shown in Figure 7 , the left side diagram is a schematic diagram of the B scan position, and the right side diagram is a B scan result, and then the damage depth is 3.64 mm.

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

[0127] As shown in Figure 8As shown, according to the temperature cloud chart, the simulated damage depth is 3.01 mm, and the error with the real test is 17.3%.

[0128] It can be seen that the lightning damage prediction device 100 of the embodiment can simulate the damage result of the three-dimensional woven composite material after lightning strike more accurately, and is beneficial to lightning damage prediction and evaluation of the aircraft engine blade made of the three-dimensional woven composite material.

[0129] Effects of the embodiment

[0130] According to the three-dimensional woven composite material lightning damage prediction device and method, 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, the unnecessary calculation power is reduced, and a simulation model capable of accurately reflecting the characteristics of the three-dimensional woven composite material is constructed; on the other hand, the influence of lightning strike at each time step is evaluated by the pyrolysis calculation unit, so that the final accurate damage result of the three-dimensional woven composite material plate model is obtained. In summary, the device and method can accurately predict the damage result of the three-dimensional woven composite material after lightning strike.

[0131] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A three-dimensional woven composite material lightning damage prediction device for obtaining lightning damage results of a three-dimensional woven composite material, characterized in that: include: a key area model construction module, configured to obtain parameters of the three-dimensional woven composite material and construct a key area model according to the parameters; a non-critical area model construction module, configured to construct a macroscopic uniform model as a non-critical area model based on the three-dimensional woven composite material; A coupling module, configured to bind and couple 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 load and thermal radiation conditions; a lightning strike calculation module, configured to calculate the damage area and damage depth as the lightning strike damage result based on the boundary conditions, the lightning current load, the thermal radiation conditions, and the three-dimensional woven composite material plate model; Wherein, the lightning strike calculation module includes: a variable calculation unit, configured to calculate the electric field intensity, electric potential, current density, and temperature of each time step based on the boundary conditions, the lightning current load, the thermal radiation conditions, and the three-dimensional woven composite material plate model; a breakdown determination unit storing the dielectric breakdown strength and configured to determine, after each time step, based on the electric potential, whether the electric potential difference of each portion of the three-dimensional woven composite material plate model is greater than or equal to the dielectric breakdown strength, and if so, increase the insulator conductivity and the conductor conductivity of the portion; a pyrolysis calculation unit storing a pyrolysis temperature and 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 based on all the parts damaged by lightning.

2. The three-dimensional woven composite material lightning damage prediction device according to claim 1, Its characteristics are: in, The key area model building module includes: An RVE construction unit, configured to obtain parameters of the three-dimensional woven composite material at a microscopic scale and construct an RVE geometric model according to the parameters; a performance parameter measuring unit, configured to obtain performance parameters of the three-dimensional woven composite material according to a test standard; a property setting unit, configured to set 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 based on the performance parameters. If so, the RVE geometric model is used as the key area model; if not, the function of 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 two corresponding 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, 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 includes thermal conductivity in the warp, weft and thickness directions.

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 four non-critical areas and a central critical area. The surrounding non-critical areas are the non-critical area models. 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 electrical conductivity of the insulator at the corresponding portion is increased by 6 orders of magnitude, and the electrical 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, for obtaining 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 based on 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 based on the boundary conditions, the lightning current load, the heat radiation conditions 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 based on 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, determining 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 based on 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, increase the time step by 1 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: Calculate the damage area and the damage depth based on all the parts damaged by lightning.

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