A method for designing a high-power-resistant composite material for a radome

Abstract

This application relates to the field of radome technology, and more specifically, to a design method for high-power resistant composite materials for radomes, comprising the following steps: Step 1: Calculate the heat generation power per unit area of ​​each layer of the radome based on its structure, dimensions, and dielectric properties; Step 2: Calculate the maximum temperature reached by the radome during its operating time using finite element simulation analysis based on the law of conservation of energy; Step 3: Evaluate whether the temperature resistance of each layer of the radome material meets the evaluation temperature calculated in Step 2. This application, through simulation of composite material data, realizes the design of composite materials for high-power resistant radomes, reveals the contribution law of various intrinsic properties of materials to their application in high-power resistant radomes, and proposes limitations and specifications for the application of intrinsic material parameters in high-power resistant radomes, which can be used to guide the design and material selection of high-power radomes.

Description

Technical Field

[0001] This application relates to the field of radome technology, and more specifically, to a design method for a radome made of high-power composite materials. Background Technology

[0002] Under the influence of strong electromagnetic pulse radiation, the radar radome's wave-transparent composite material will generate a large amount of electromagnetic heat, causing the temperature to rise. At the same time, the thermal conductivity of commonly used core materials such as honeycomb and foam, as well as the skin, in existing radar radome structures is very low, leading to obstructed heat dissipation, heat accumulation, and further temperature increases. This causes the internal temperature of the structure to exceed the material's temperature resistance limit, resulting in ablation and causing the radar radome's wave-transparent performance to fail or even be completely destroyed.

[0003] Therefore, there is an urgent need to develop a data simulation design method for radome composite materials.

[0004] Patent CN201510063994.6 discloses a design method for a high-power, wideband radar radome, belonging to the technical field of large ground-based radar radomes. This method addresses the problem that current radome design methods based on material research are not suitable for large ground-based radomes. The method includes: obtaining the maximum power density of antenna radiation under wideband conditions based on the array antenna aperture field; selecting the material and structural parameters of the radome wall; obtaining the electromagnetic radiation energy absorption coefficient; and then, combining this with the energy conservation of radome heat transfer, obtaining the temperature of the radome under high-power irradiation; determining whether the temperature resistance value of the current radome wall material is greater than the obtained temperature. If so, the radome is the final design; otherwise, the radome structural material is reselected and the design is reworked. This method is used to design large ground-based radar radomes.

[0005] However, the design methods of the aforementioned prior art do not limit the intrinsic properties of materials for the requirements of power-tolerant radomes, and lack guidance for material selection in actual power-tolerant radome design. Summary of the Invention

[0006] This application provides a design method for high-power resistant composite materials for radomes. Through simulation of composite material data for radomes, the design of composite materials for high-power resistant radomes is realized. The method reveals the contribution law of various intrinsic properties of materials to their application in high-power resistant radomes and proposes limitations and specifications for the application of intrinsic parameters of materials in high-power resistant radomes. This method can be used to guide the design of high-power radomes and the selection of materials.

[0007] This application provides a design method for high-power resistant composite materials for radomes, specifically including the following: A design method for a radome made of high-power resistant composite materials includes the following steps: Step 1: Based on the structure, dimensions, and dielectric properties of each layer of the radome, and considering the total number of radome layers (n), calculate the heat generation power per unit area for each layer from 1 to n. The heat generation power per unit area of ​​each layer of the radome is... 热1 ... 热n The calculation formula is as follows: 热1 = P 总热 × ; ...... 热n = P 总热 × ; in, '1, ''2, ''3...... '' n The dielectric loss of each layer of the radome is calculated using the dielectric loss tangent and dielectric constant of each layer; P 总热 The total heat generation power per unit area of ​​the radome is calculated based on the required power density of the radome; d1……d n The thickness of each layer of the radome; Step 2: Based on the law of conservation of energy, finite element simulation analysis is performed. The software used includes ANSYS finite element analysis software, and the input parameters are as follows: ① Establish a structural model of the radome, including the thicknesses of each layer of the radome, d1...d2. n ; ② The heat source of each layer of the input radome, i.e., the heat power per unit area is 热1 ... 热n ,in P 总热 = 热1 +……+ 热n ; ③ Input radar operating time is t 工作 ; ④ Considering heat transfer between layers, input the thermal conductivity K of each layer material. f1 ...K fn ; ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外 (W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); ⑥ Considering the temperature rise of each layer, input the material density of each layer. (kg / m 3 Input the specific heat capacity C (J / (kg·K)) of each layer of material. ⑦ Considering out-of-plane radiation, input the blackbody emissivity λ1……λ of each layer of material. n ; ⑧ Input the initial temperature T0 (K) of the radome and the ambient temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; Step 3: Evaluate whether the temperature resistance of each layer of the radome meets the evaluation temperature calculated in Step 2. If yes, the radome meets the power resistance design requirements. If not, materials with better dielectric properties, temperature resistance, and / or heat dissipation performance need to be selected to design the radome. Return to Step 1 for re-verification.

[0008] By adopting the above technical solution, during the finite element simulation analysis, once the radome achieves thermal equilibrium, the heat generated by the radome per unit time equals the sum of the radome's heat dissipation and the blackbody's radiated heat. At this point, the temperature of the radome no longer rises, and t is obtained. 平衡 Moreover, when t 工作 ≥t 平衡 At that time, the radome working time t 工作 The temperature of the radome and t 平衡 The radome temperature is the same. Therefore, when t 工作 <t 平衡 When the output radome operates for time t 工作 The radome temperature is used as the evaluation temperature; when t 工作 ≥t 平衡 When the output radome operates for time t 平衡 The radome temperature is used as the evaluation temperature.

[0009] Additionally, it should be noted that in the technical solution of this application, n is an integer greater than or equal to 1, where n is 1, i.e., the radome is a single-layer structure. The heat power generated per unit area of ​​each layer of the radome is... 热1 The calculation formula is as follows: 热1 = P 总热 .

[0010] In addition, the order of the subscripts of each symbol is only for the convenience of indicating the corresponding layer number; the specific values ​​of the parameters of different layers can be the same or different.

[0011] Furthermore, in step one, the calculation of dielectric loss includes the following steps: ① The electromagnetic parameters of each layer of material, calculated by the loss tangent, are tan θ. 1……tan n The dielectric constant is calculated as follows: '1…… ' n ; ② Calculate the dielectric loss of each layer ''1= '1×tan 1…… '' n = ' n ×tan n .

[0012] Furthermore, in step one, the wave-transmitting structure of the radome is designed according to the frequency band requirements of the radome, and the power transmittance T of the radome in that frequency band is confirmed. 2 Power reflectivity R 2 Calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 The process of calculating the total heat generation power of the radome according to the required power density is as follows: Total heat generation power per unit area (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( ).

[0013] By adopting the above technical solution, according to the law of conservation of energy, the power loss rate of the radome is the thermal conversion rate generated when electromagnetic waves pass through the radome. The maximum thermal conversion rate in the required frequency band is calculated, which is the thermal conversion rate required by this application. ).

[0014] In addition, power transmittance T 2 Power reflectivity R 2 It can be obtained through simulation calculations or testing methods.

[0015] Furthermore, in step three, the evaluation method for assessing the temperature resistance performance of each layer of the radome material includes at least one of the following methods: ① The glass transition temperature of the resin-based composite material should be at least 30°C higher than the maximum temperature reached by the material in step two; ②The retention rate of mechanical properties of the resin-based composite material at the maximum temperature reached in step two is ≥70%; ③ The melting point and decomposition temperature of ceramic materials should be 0.8 times higher than the maximum temperature reached in step two.

[0016] By adopting the above technical solution, the maximum temperature mentioned above is the evaluation temperature obtained in step two.

[0017] Furthermore, the radome structure involved in the design method includes a single-layer radome or a multi-layer radome.

[0018] Furthermore, the dielectric constant of each layer of the radome material involved in the design method ranges from 1 to 10, and the dielectric loss tangent ranges from 0.001 to 0.1.

[0019] Furthermore, the materials used in the antenna radome layers of the design method include at least one of fiber-reinforced resin-based composite materials, ceramic-based materials, honeycomb materials, and foam materials.

[0020] In summary, this application has the following beneficial effects: 1. The design method of this invention performs power resistance design for each layer of the sandwich radome, which can clearly define the power resistance boundary of each layer of material. This is conducive to the refined design of the power resistance performance of the radome from the perspective of material performance, and maximizes the efficiency of the power resistance performance of materials in the radome design.

[0021] 2. By inputting experimental or simulation data into finite element calculations, the accuracy of calculations and the efficiency of simulation iterations are improved, providing a calculation basis for rapid iteration of radome design.

[0022] 3. This patent sets limits and specifications for the application of intrinsic material parameters in power-resistant radomes, which can be used to guide the design of power-resistant radomes and the selection of materials. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method provided in this application; Figure 2 This is a schematic diagram of the A-layer radome structure in Embodiment 3; Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the C-layer radome structure in Embodiment 3; Figure 5 yes Figure 4 Enlarged view of point B in the middle.

[0024] Explanation of reference numerals in the attached drawings: 1. Outer skin of A-layer radome; 2. Core material of A-layer radome; 3. Inner skin of A-layer radome; 4. Outer skin of C-layer radome; 5. First core material of C-layer radome; 6. Middle skin of C-layer radome; 7. Second core material of C-layer radome; 8. Inner skin of C-layer radome. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] This application provides a design method for a radome made of high-power resistant composite materials, such as... Figure 1 As shown, according to the order of operations, the main steps include: Step 1: Design the structure according to the radome frequency band and wave transmission requirements, and obtain the power transmittance and power reflectance through testing or calculation.

[0027] Step 2: Based on the results of Step 1, calculate the maximum heat conversion rate according to the law of conservation of energy. The maximum heat conversion rate is also known as the power loss rate. .

[0028] Step 3: Calculate the total heat generation power per unit area based on the required power density of the radome.

[0029] Step 4: Calculate the heat generation power per unit area of ​​the nth layer of the radome based on the structure, size and dielectric properties of each layer.

[0030] Step 5: Perform finite element simulation based on the modeling in Step 4, and output the temperature reached by each layer of the radome.

[0031] Step 6: Evaluate whether the temperature resistance of each layer of the radome meets the temperature output in Step 5. If yes, the radome meets the power resistance design requirements. If no, select materials with better dielectric properties, temperature resistance, and / or heat dissipation performance to design the radome and return to Step S1 for re-verification.

[0032] Based on the above steps, the specific operations for each step are as follows: Step 1: Design the radome's wave-transmitting structure according to the radome's frequency band requirements, and confirm the radome's power transmittance T in that frequency band. 2 Power reflectivity R 2 ; Step 2: Calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 ; Step 3: Calculate the total heat generation power of the radome according to the required power density. The process is as follows: Total heat generation power per unit area (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( ); Step 4: Calculate the thermal power of each layer of the radome, including the following steps: ① The radome has a total of n layers, where n is an integer greater than or equal to 1. The thickness of each corresponding layer of the radome is d1...d2. n ; ② The electromagnetic parameters of each layer of material, calculated by the loss tangent, are tan θ. 1……tan n The dielectric constant is calculated as follows: '1…… ' n ; ③ Calculate the dielectric loss of each layer ''1= '1×tan 1…… '' n = ' n ×tan n ; ④ The heat power generated per unit area of ​​each layer of the radome is 热1 ... 热n The calculation formula is as follows: 热1 = P 总热 × ; ...... 热n = P 总热 × ; Step 5: Based on the law of conservation of energy, use ANSYS finite element analysis software and input the following parameters: ① Establish a structural model of the radome, including the thicknesses of each layer of the radome, d1...d2. n ; ② The heat source of each layer of the input radome, i.e., the heat power per unit area is 热1 ... 热n ,in P 总热 = 热1 +……+ 热n ; ③ Input radar operating time is t 工作 ; ④ Considering heat transfer between layers, input the thermal conductivity K of each layer material. f1 ...K fn ; ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外(W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); ⑥ Considering the temperature rise of each layer, input the material density of each layer. (kg / m 3 Input the specific heat capacity C (J / (kg·K)) of each layer of material. ⑦ Considering out-of-plane radiation, input the blackbody emissivity λ1……λ of each layer of material. n ; ⑧ Input the initial temperature T0 (K) of the radome and the ambient temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; Step 6: Evaluate whether the temperature resistance of each layer of the radome meets the evaluation temperature calculated in Step 2; if yes, the radome meets the power resistance design requirements; if no, materials with better dielectric properties, temperature resistance and / or heat dissipation performance need to be selected to design the radome and return to Step 1 for re-verification.

[0033] The evaluation methods for assessing the temperature resistance performance of each layer of the radome material include at least one of the following methods: ① The glass transition temperature of the resin-based composite material should be at least 30°C higher than the maximum temperature reached by the material in step 5; ②The retention rate of mechanical properties of the resin-based composite material at the maximum temperature reached in step 5 is ≥70%; ③ The melting point and decomposition temperature of ceramic materials should be 0.8 times higher than the maximum temperature reached in step 5.

[0034] The following explanation is provided through specific examples.

[0035] Example 1 This embodiment designs a power density index of 50W / cm². 2 A single-layer radome.

[0036] Based on the power density specifications and structure, following the design method below, materials with different dielectric properties are selected. The dielectric loss tangent is set as a variable, while other material parameters remain consistent. The required temperature resistance of the materials can then be obtained. The design steps are as follows: S1, design the radome according to the frequency band of 6GHz~18GHz. Design a single-layer composite material structure with a thickness of 6mm. Set up a material system with a gradient dielectric loss tangent.

[0037] The structure and dielectric properties of the radome are shown in Table 1.

[0038] Table 1 Material Parameters of Example 1 The power transmittance T of each material was calculated using the "Test Method for Transmittance of Radar Transmitting Materials" (GJB7954-2012). 2 Power reflectivity R 2 The details are as follows: Material 1: Radome power transmittance T 2 =87.97%, power reflectivity R 2 =10.37%; Power transmittance T of radome, material 2 2 =86.52%, power reflectivity R 2 =10.21%; Material 3: Radome power transmittance T 2 =82.32%, power reflectivity R 2 =9.76%.

[0039] S2, calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 ; Based on this, the maximum power loss rate of material 1 in this frequency band is obtained. =1-T 2 -R 2 =1.65%; Maximum power loss rate of material 2 =1-T 2 -R 2 =3.27%; Maximum power loss rate of material 3 =1-T 2 -R 2 =7.91%.

[0040] S3. The required power density of the radome is 50W / cm³. 2 The calculation process for the total heat generation power per unit area is as follows: Material 1: Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×1.65% = 0.826 W / cm² 2 Material 2: Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×3.27% = 1.635W / cm² 2 ; Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总) × heat conversion rate ( =50W / cm 2 ×7.91% = 3.957 W / cm 2 .

[0041] S4. Calculate the heat generated by a single-layer radome based on the radome structure design and material parameters: ①The A-layer radome has one layer, and the thickness of the radome layer is designed to be d1; ②The loss tangent of a single layer is tan The dielectric constant of a single layer is '1; ③ Dielectric loss ''1= '1×tan 1; ④ The heat power generated per unit area of ​​a single layer of the radome is 热1 P 总热 = 热1 ; 热1 = P 总热 × Therefore, the thermal power of each layer of material is shown in Table 2.

[0042] Table 2 Calculated values ​​of heat power per unit area of ​​each layer of material in Example 1 S5. Radome Thermal Balance Calculation According to the law of conservation of energy, the total heat generation power per unit area of ​​the radome is P. 总热 The heat power of a single layer is 热1 The finite element simulation analysis software used in this embodiment is ANSYS, and the input parameters are shown in Table 3.

[0043] Table 3. Parameters input for some finite element simulation analyses in Example 1 ① Establish a structural model of the radome, including the thickness d1 of each layer of the radome; ② The heat source of each layer of the input radome, i.e., the heat power per unit area is 热1 ,in P 总热 = 热1 ; ③ Input radar operating time is t 工作 ; ④ Considering heat transfer between layers, input the thermal conductivity K of each layer material. f1 ; ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外 (W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); ⑥ Considering the temperature rise of each layer, input the material density of each layer. (kg / m 3 Input the specific heat capacity C (J / (kg·K)) of each layer of material. ⑦ Considering out-of-plane radiation, input the blackbody emissivity λ1 of each layer of material; ⑧ Input the initial temperature T0 (K) of the radome and the ambient temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; S6. Power handling performance assessment of the radome: Based on the simulation analysis results above, the highest temperature of each layer of the radome was output and compared with the temperature resistance performance of the material to determine that the radome meets the power resistance index. The results are shown in Table 4.

[0044] Table 4. Maximum temperature of each layer of material in Example 1 of the antenna radome. The design results show that, with other material properties remaining consistent, the heat generated by the radome increases and the temperature rises as the material's loss tangent increases. Material 1 has a loss tangent of 0.004, and the highest radome temperature is 211.085℃; a composite material with a glass transition temperature greater than 241℃ is recommended. Material 2 has a loss tangent of 0.008, and the highest radome temperature is 396.682℃; a ceramic-based material with a melting point and decomposition temperature greater than 495.85℃ is recommended. Material 3 has a loss tangent of 0.02, and the highest radome temperature is 912.763℃; a ceramic-based material with a glass transition temperature greater than 1140.95℃ is recommended. Evaluate whether the material's temperature resistance meets the above design requirements. If it does, output the radome design; if not, select a material with better dielectric properties, temperature resistance, and / or heat dissipation performance to design the radome and return to step S1 for re-verification.

[0045] Example 2 This embodiment designs a power density index of 50W / cm². 2 A single-layer radome.

[0046] Based on the power density index and structure, following the design method below, materials with different dielectric properties are selected, the dielectric constant is set as a variable, and other material parameters remain the same, to obtain the material temperature resistance requirements. The design steps are as follows: S1, design the radome for the frequency band 6GHz~18GHz. Design a single-layer composite material structure with a thickness of 6mm. Set up a material system with a gradient dielectric constant.

[0047] The structure and dielectric properties of the radome are shown in Table 5.

[0048] Table 5 Material Parameters of Example 2 The power transmittance T of each material was calculated using the "Test Method for Transmittance of Radar Transmitting Materials" (GJB7954-2012). 2 Power reflectivity R 2 The details are as follows: Material 1: Radome power transmittance T 2 =87.97%, power reflectivity R 2 = 10.37%; Power transmittance T of radome (material 2) 2 =89.98%, power reflectivity R 2 =8.33%; Material 3: Radome power transmittance T 2 =91.83%, power reflectivity R 2 =6.42%.

[0049] S2, calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 ; Based on this, the maximum power loss rate of material 1 in this frequency band is obtained. =1-T 2 -R 2 =1.65%; Maximum power loss rate of material 2 =1-T 2 -R 2 =1.69%; Maximum power loss rate of material 3 =1-T 2 -R 2 =1.75%.

[0050] S3. The required power density of the radome is 50W / cm³. 2 The calculation process for the total heat generation power per unit area is as follows: Material 1: Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm2 ×1.65% = 0.826 W / cm² 2 Material 2: Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×1.69% = 0.847 W / cm² 2 ; Total heat generation power per unit area of ​​the radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×1.75% = 0.876 W / cm 2 .

[0051] S4. Calculate the heat generated by a single-layer radome based on the radome structure design and material parameters: ①The A-layer radome has one layer, and the thickness of the radome layer is designed to be d1; ②The loss tangent of a single layer is tan 1; The dielectric constant of a single layer is '1; ③ Dielectric loss ''1= '1×tan 1; ④ The heat power generated per unit area of ​​a single layer of the radome is 热1 P 总热 = 热1 ; 热1 = P 总热 × Therefore, the thermal power of each layer of material is shown in Table 6.

[0052] Table 6 Calculated values ​​of heat power per unit area of ​​each layer of material in Example 2 S5. Radome Thermal Balance Calculation According to the law of conservation of energy, the total heat generation power per unit area of ​​the radome is P. 总热 The heat power of a single layer is 热1 The finite element simulation analysis software used in this embodiment is ANSYS, and the input parameters are shown in Table 7.

[0053] Table 7 shows some of the input parameters for the finite element simulation analysis in Example 2. ① Establish a structural model of the radome, including the thickness d1 of each layer of the radome; ② The heat source of each layer of the input radome, i.e., the heat power per unit area is 热1 ,in P 总热 = 热1 ; ③ Input radar operating time is t 工作 ; ④ Considering heat transfer between layers, input the thermal conductivity K of each layer material. f1 ; ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外 (W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); ⑥ Considering the temperature rise of each layer, input the material density of each layer. (kg / m 3 ), input the specific heat capacity C (J / (kg·K)) of each layer of material; ⑦ Considering out-of-plane radiation, input the blackbody emissivity λ1 of each layer of material; ⑧ Input the initial temperature T0 (K) of the radome and the ambient temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; S6. Power handling performance assessment of the radome: Based on the simulation analysis results above, the highest temperature of each layer of the radome is output and compared with the temperature resistance performance of the materials. The radome was determined to meet the power tolerance requirements. The results are shown in Table 8.

[0054] Table 8. Maximum temperature of each layer of material in Example 2. The design results show that other material properties remain consistent. As the dielectric constant of the material increases, the heat generated by the radome increases and the temperature rises, but the impact is relatively small. Material 1 has a dielectric constant of 3.2, and the highest radome temperature is 211.085℃. A composite material with a glass transition temperature greater than 241℃ is recommended. Material 2 has a dielectric constant of 3.8, and the highest radome temperature is 215.929℃. A composite material with a glass transition temperature greater than 246℃ is recommended. Material 3 has a dielectric constant of 4.5, and the highest radome temperature is 222.57℃. A composite material with a glass transition temperature greater than 253℃ is recommended. Evaluate whether the material's temperature resistance meets the above design requirements. If it does, output the radome design; if not, select a material with better dielectric properties, temperature resistance, and / or heat dissipation performance to design the radome and return to step S1 for re-verification.

[0055] Example 3 This embodiment designs a power density index of 50W / cm². 2 A sandwich structure radome.

[0056] Based on the power density specifications and structure, and following the design method, two schemes, A-layer structure and C-layer structure, using the same materials, are selected for the design of the radome's power-resistant composite material. The A-layer structure is as follows: Figure 2 and Figure 3 As shown, the radome, from the outside to the inside, consists of: A-layer radome outer skin 1, A-layer radome core material 2, and A-layer radome inner skin 3. The C-layer structure is as follows... Figure 4 and Figure 5 As shown, the radome consists of, from the outside to the inside, the outer skin of the C-layer radome 4, the first core material of the C-layer radome 5, the middle skin of the C-layer radome 6, the second core material of the C-layer radome 7, and the inner skin of the C-layer radome 8.

[0057] The temperature generated by the radome can be obtained. The design steps are as follows: S1. Based on the power density index and structure, and following the design method, two schemes, A-layer structure and C-layer structure, using the same materials, are designed for the radome's power-resistant composite material. The temperature generated by the radome can be obtained. The design steps are as follows.

[0058] The structure and dielectric properties of the radome are shown in Table 9.

[0059] Table 9 Material Parameters of Example 3 The power transmittance T of each interlayer was calculated using the "Test Method for Transmittance of Radar Transmitting Materials" (GJB7954-2012). This value was obtained when the loss rate was at its maximum. 2 Power reflectivity R 2 The details are as follows: A sandwich radome power transmittance T 2 = 88.23%, power reflectivity R 2 =10.85%; C-layer radome power transmittance T 2 = 81.35%, power reflectivity R 2 =17.01%.

[0060] S2, calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 ; Based on this, the maximum power loss rate of the A-layer radome in this frequency band was obtained. =1-T 2 -R 2 =0.92%; Maximum power loss rate of C-layer radome =1-T 2 -R 2 =1.64%.

[0061] S3. The required power density of the radome is 50W / cm³. 2 The calculation process for the total heat generation power per unit area is as follows: A. Total heat generation power per unit area of ​​the sandwich radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×0.92% = 0.460 W / cm² 2 ; Total heat generation power per unit area of ​​the C-layer radome (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( =50W / cm 2 ×1.64% = 0.819 W / cm² 2 .

[0062] S4. Calculate the heat generated in each layer of the sandwich radome A based on the radome structure design and material parameters: ① A sandwich radome has three layers, and the thickness of each layer is designed to be d1, d2, and d3; C sandwich radome has five layers, and the thickness of each layer is designed to be d1, d2, d3, d4, and d5. ② The heat power generated per unit area of ​​each layer of the A-layer radome is 热1 , 热2 , 热3 P 总热 = 热1 + 热2 + 热3 The thermal power generated per unit area of ​​each layer of the C-layer radome is: 热1 , 热2 , 热3 , 热4 , 热5 P 总热 = 热1 + 热2 + 热3 + 热4 + 热5 ③ The loss tangent of each layer of the A-layer radome is tan tangent. 1. tan 2. tan 3; The loss tangent of each layer of the C-layer radome is tan 1. tan 2. tan 3. tan 4. tan 5; ④ The dielectric constant of each layer of the A-layer radome is '1、 '2、 '3; The dielectric constant of each layer of the C-layer sandwich radome is '1、 '2、 '3、 '4、 '5; ⑤ Dielectric loss of each layer ''1= '1×tan 1, ''2= '2×tan 2, ''3= '3×tan 3, ''4= '4×tan 4, '5= '5×tan 5.

[0063] Since the sandwich radome in this embodiment has a layered structure of the same material, the dielectric constant and dielectric loss of each layer are not numbered in order in the symbol representation in the calculation of thermal power per unit area, but this does not affect its contribution to the final result.

[0064] The thermal power per unit area of ​​each layer of the A-layer radome is: 热1 = P 总热 × , 热2 = P 总热 × , 热3 = P 总热 × ; Similarly, the thermal power per unit area of ​​each layer of the C-layer radome is: 热1 = P 总热 × , 热2 = P 总热 × , 热3 = P 总热 × , 热4 = P 总热 × , 热5 = P 总热 × , Therefore, the thermal power of each layer of material is shown in Table 10.

[0065] Table 10 Calculated values ​​of heat power generated per unit area of ​​each layer of material in Example 3 S5. Radome Thermal Balance Calculation According to the law of conservation of energy, the total heat generation power per unit area is P. 总热 The heat power of each layer of interlayer A is 热1 , 热2 , 热3 The heat power of each layer of the C interlayer is 热1 , 热2 , 热3 , 热4 , 热5 The finite element simulation analysis software used in this embodiment is ANSYS, and the input material parameters are shown in Table 11.

[0066] Table 11 shows some of the parameters input for the finite element simulation analysis in Example 3. ①Establish structural models of the A-layer and C-layer radomes. ② Input antenna radome heat source, i.e., the heat power of each layer of the structure is respectively 热1 , 热2 , 热3 , 热4 , 热5 ; ③ Input radar operating time is t 工作 ; ④ Considering heat transfer between layers, input the thermal conductivity K of each layer material. f1 K f2 K f3 K f4 K f5 .

[0067] ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外 (W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); ⑥ Considering the temperature rise of each layer, input the material density of each layer. (kg / m 3 ),Right now 1. 2. 3. 4. 5; Input the specific heat capacity C (J / (kg·K)) of each layer of material, i.e. 1. 2. 3. 4. 5; ⑦ Considering out-of-plane radiation, input the blackbody emissivity λ1, λ2, λ3, λ4, λ5 of each layer material; ⑧ Input the initial temperature T0 (K) of the radome and the ambient temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; S6. Power handling performance assessment of the radome: Based on the simulation analysis results above, the highest temperature of each layer of the radome was output and compared with the temperature resistance performance of the material to determine that the radome meets the power resistance index. The results are shown in Table 12.

[0068] Table 12 Maximum Temperature of Radome Layers in Example 3 (Example 3) The design results show that the material properties are consistent, but the temperature generated by the A-layer radome is lower than that generated by the C-layer radome. The highest temperature of the A-layer radome skin is 147.549℃, and it is recommended to use a composite material with a glass transition temperature greater than 178℃; the highest temperature of the core material is 158.089℃, and it is recommended to use materials such as foam or honeycomb with a mechanical strength retention rate greater than 80% at 160℃. The highest temperature of the C-layer radome skin is 364.562℃, and it is recommended to use a composite material with a glass transition temperature greater than 395℃; the highest temperature of the core material is 364.557℃, and it is recommended to use ceramic materials with a melting point and decomposition temperature greater than 456℃. Evaluate whether the temperature resistance of the materials meets the above design requirements. If it does, output the radome design; if not, select materials with better dielectric properties, temperature resistance, and / or heat dissipation performance to design the radome and return to step S1 for re-verification.

[0069] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method of designing a high power radome composite material, characterized in that, Includes the following steps: Step 1: Based on the structure, dimensions, and dielectric properties of each layer of the radome, and considering the total number of radome layers (n), calculate the heat generation power per unit area for each layer from 1 to n. The heat generation power per unit area of ​​each layer of the radome is... 热1 ... 热n The calculation formula is as follows: 热1 = P 总热 × ； ...... 热n = P 总热 × ； in, '1, ''2, ''3...... '' n The dielectric loss of each layer of the radome is calculated using the dielectric loss tangent and dielectric constant of each layer; P 总热 The total heat generation power per unit area of ​​the radome is calculated based on the required power density of the radome; d1……d n The thickness of each layer of the radome; Step 2: Based on the law of conservation of energy, finite element simulation analysis is performed. The software used includes ANSYS finite element analysis software, and the input parameters are as follows: ① Establish a structural model of the radome, including the thicknesses of each layer of the radome, d1...d2. n ; ② Input the heat source of each layer of the radome, i.e., the heat power per unit area is 热1 ... 热n ,in P 总热 = 热1 +……+ 热n ; ③ Input radar operating time is t 工作 ; (4) Consider the heat transfer of each layer, input the thermal conductivity K of each layer material f1 .........K fn ; ⑤ Considering the heat transfer from the air inside and outside the radome, the heat convection coefficient input to the outer surface of the radome is... 外 (W / (m·K)), the thermal convection coefficient of the inner surface of the input radome. 内 (W / (m·K)); (6) Considering the temperature rise of each layer, input the density of each layer of material (kg / m 3 ), and the specific heat capacity C of each layer of material (J / (kg·K)​ Consider the out-of-plane radiation, input each layer material blackbody radiation emissivity λ1 … λ n ; 8. Input radome initial temperature T0 (K) and external environment temperature T ext (K); ⑨ Set up transient simulation and output the highest temperature of the radome according to the radar's operating time as the evaluation temperature; Step 3: Evaluate whether the temperature resistance of each layer of the radome meets the evaluation temperature calculated in Step 2. If yes, the radome meets the power resistance design requirements. If not, materials with better dielectric properties, temperature resistance, and / or heat dissipation performance need to be selected to design the radome and return to Step 1 for re-verification.

2. The method of designing a high power radome composite material according to claim 1, wherein, In step one, the calculation of dielectric loss includes the following steps: 1 … tan n ; dielectric constant is ’1… ’ n ;​ ② Calculate the dielectric loss of each layer ''1= '1×tan 1…… '' n = ' n ×tan n .

3. The design method of a high power radome composite material according to claim 1, wherein, In step one, the wave-transmitting structure of the radome is designed according to the frequency band requirements, and the power transmittance T of the radome in that frequency band is confirmed. 2 Power reflectivity R 2 Calculate the power loss rate of the radome in this frequency band. =1-T 2 -R 2 The process of calculating the total heat generation power of the radome according to the required power density is as follows: Total heat generation power per unit area (P) 总热 = Antenna total power density (P) 总 ) × heat conversion rate ( ).

4. The design method of a high power composite radome according to claim 1, wherein, In step three, the evaluation method for assessing the temperature resistance performance of each layer of the radome material includes at least one of the following methods: ① The glass transition temperature of the resin-based composite material should be at least 30°C higher than the maximum temperature reached by the material in step two; ②The retention rate of mechanical properties of the resin-based composite material at the maximum temperature reached in step two is ≥70%; ③ The melting point and decomposition temperature of ceramic materials should be 0.8 times higher than the maximum temperature reached in step two.

5. The design method of a high power composite radome according to claim 1, wherein, The design method involves radome structures including single-layer radomes or multi-layer radomes.

6. The design method of a high power composite radome according to claim 1, wherein, The dielectric constant of each layer of the radome material involved in the design method ranges from 1 to 10, and the dielectric loss tangent ranges from 0.001 to 0.

1.

7. The design method of a high power composite radome according to claim 4, wherein, The design method involves radome materials for each layer, including at least one of fiber-reinforced resin-based composite materials, ceramic-based materials, honeycomb materials, and foam materials.

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