Homogeneous composite material, composite material system, stacking structure and radiation protection material design method

Abstract

The invention provides a homogeneous composite material, a composite material system, a stacking structure and a radiation protection material design method, and relates to the technical field of space radiation protection materials.The homogeneous composite material is prepared from, by mass, 10-30% of epoxy resin, 10-90% of bismuth trioxide and the balance polyethylene and boron nitride which are equal in mass fraction. According to the invention, the radiation protection material with radiation resistance and light weight can be designed.

Description

Technical Field

[0001] The present invention relates to the technical field of space radiation protection materials, and in particular to a homogeneous composite material, a composite material system, a stacking structure and a radiation protection material design method. Background Art

[0002] With the rapid development of deep space exploration missions, spacecraft are exposed to complex cosmic radiation environments for a long time, and the selection and design of traditional protective materials face severe challenges.

[0003] In related technologies, spacecraft mostly use aluminum as the mainstream protective material, which has high density characteristics and limited radiation protection performance, or use multi-layer composite materials, which limits the spacecraft's payload and makes it difficult to adapt to the comprehensive protection needs under different space radiation conditions. Summary of the Invention

[0004] The problem to be solved by the present invention is that the selection and design of protective materials in the related art have limited radiation protection performance and are difficult to meet comprehensive protection needs.

[0005] To solve the above problems, in a first aspect, the present invention provides a homogeneous composite material comprising 10-30% by mass of epoxy resin, 10-90% by mass of bismuth trioxide, and the rest being equal mass fractions of polyethylene and boron nitride.

[0006] The homogeneous composite material provided by the present invention can improve the radiation resistance of the homogeneous composite material to different radiation particles in different orbital environments (such as as a protective material for spacecraft). By adjusting the mass fraction of bismuth trioxide, the overall weight of the protective material can be changed, so that the protective material of the spacecraft has both radiation resistance and light weight.

[0007] In a second aspect, the present invention provides a composite material system, comprising a plurality of homogeneous composite materials as described above, wherein each of the homogeneous composite materials has a different density.

[0008] By adjusting the mass fraction of bismuth trioxide, homogeneous composite materials with different densities can be obtained. Since the density of each homogeneous composite material is different, the composite material system contains different density systems, which are specifically manifested as different Bi2O3. The performance of different homogeneous composite materials in the composite material system is different. This difference can be used to optimize the radiation protection material.

[0009] In a third aspect, the present invention provides a stacking structure comprising any one of the homogeneous composite materials in the composite material system described above, and also comprising a radiation target material. The stacking structure is a flat plate geometric structure, and the homogeneous composite material and the radiation target material are both configured in sheet form and alternately stacked to form the flat plate geometric structure.

[0010] The composite material system and stacking structure provided by the present invention have the same beneficial effects as those of the homogeneous composite material over the prior art, and will not be described in detail here.

[0011] In a fourth aspect, the present invention provides a method for designing a radiation protection material, based on the stacking structure described above, comprising: Establishing a plurality of stacked structures of different mass thicknesses, wherein each stacked structure of different mass thicknesses comprises a plurality of homogeneous composite materials of different densities; Determine the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position; Performing forward Monte Carlo simulation based on the multiple stacking structures and the spacecraft radiation environment energy spectrum, and calculating the total ionizing dose of the last layer of radiation target material of each stacking structure away from the particle source under different orbits according to the number of random particle movements; According to the total ionizing dose of each stacked structure under different orbits, a trade-off curve based on aluminum of the same mass thickness under different orbits is established, and the homogeneous composite material suitable for the operation of the spacecraft under different orbits is screened according to the trade-off curve.

[0012] Optionally, establishing a plurality of stacked structures with different mass thicknesses includes: According to the plurality of homogeneous composite materials with different densities, the thickness of the homogeneous composite materials with different densities at the same mass thickness is determined, and thereby the plurality of stacking structures with different mass thicknesses are established.

[0013] Optionally, determining the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position includes: determining various orbital parameters of the spacecraft using a spacecraft orbit extrapolation model, wherein the orbital parameters include orbit type, perigee distance, apogee distance, and orbit inclination; The multiple orbital parameters are input into a space radiation environment model to determine the spacecraft radiation environment energy spectrum. The space radiation environment model includes a radiation belt electron environment model, a radiation belt proton environment model, and a solar high-energy proton environment model.

[0014] Optionally, the performing of forward Monte Carlo simulation based on the multiple stacking structures and the spacecraft radiation environment energy spectrum, and counting the total ionizing dose of the last layer of radiation target material of each stacking structure away from the particle source under different orbits according to the number of random particle operations, includes: A square surface source, a distance between the particle source and the stacked structure, and a radiation emission direction are determined based on the particle source that conforms to the spacecraft radiation environment energy spectrum, and a forward Monte Carlo simulation is performed to calculate the total ionizing dose. The radiation target material includes a silicon dose sheet.

[0015] Optionally, establishing a trade-off curve based on aluminum of the same mass and thickness under different orbits according to the total ionizing dose of each stacked structure under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve includes: The mass thickness is converted into an equivalent aluminum thickness, and the trade-off curve is constructed according to the relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks.

[0016] Optionally, converting the mass thickness into an equivalent aluminum thickness, and constructing the trade-off curve according to a relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks includes: Based on a low earth orbit, a near polar orbit, and an equatorial medium earth orbit, a corresponding relationship between the total ionizing dose and the equivalent aluminum thickness of each stacked structure is established, and a first trade-off curve is constructed.

[0017] Based on a medium earth orbit and a geostationary orbit, establishing a corresponding relationship between the total ionizing dose and the mass thickness of each stacked structure, and constructing a second trade-off curve; Therein, the stacked structures are marked by corresponding homogeneous composite materials.

[0018] Optionally, establishing a trade-off curve based on aluminum of the same mass and thickness under different orbits according to the total ionizing dose of each stacked structure under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve includes: Determining, according to the first trade-off curve, the stacking structure corresponding to the minimum total ionizing dose at the same equivalent aluminum thickness, and determining the corresponding homogeneous composite material; According to the second trade-off curve, the stacking structure corresponding to the minimum mass thickness under the total ionizing dose of the same level is determined, and the corresponding homogeneous composite material is determined.

[0019] Through the radiation protection material design method provided by the present invention, the radiation target material can be selected as silicon according to the material of the aerospace electronic components, and then a flat plate geometric structure of alternating stacking of homogeneous composite materials and thin silicon wafers (i.e., silicon dose wafers) is set. For different stacking structures, the mass thickness is determined by the density and thickness of the homogeneous composite material. The target material is a thin slice, and the thickness is not taken into account. In this way, a variety of stacking structures with different mass thicknesses are established, which can be used to simulate the radiation of radiation particles on the radiation target material under different energy distributions and orbital conditions. Based on the performance of the radiation shielding effect of the homogeneous composite material in the stacking structure, the optimal composite material under different energy distributions and orbital conditions can be screened to obtain a radiation protection material that has both radiation resistance and composite lightweight requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a stacking structure according to an embodiment of the present invention is shown; Figure 2 A schematic diagram showing a process flow of a radiation protection material design method according to an embodiment of the present invention is shown; Figure 3 A schematic diagram showing the relationship between energy and flux in the AE9 model according to an embodiment of the present invention is shown; Figure 4 Schematic diagram showing the relationship between energy and flux in the AP9 model according to an embodiment of the present invention; Figure 5 A schematic diagram showing the relationship between energy and flux in the SAPPHIRE model according to an embodiment of the present invention is shown; Figure 6 A trade-off curve diagram based on aluminum under LEO orbit according to an embodiment of the present invention is shown; Figure 7 A partial enlarged view of a trade-off curve diagram based on aluminum under LEO orbit according to an embodiment of the present invention is shown; Figure 8 A trade-off curve diagram based on aluminum under the LEPO track according to an embodiment of the present invention is shown; Figure 9 A partial enlarged view of a trade-off curve diagram based on aluminum under a LEPO track according to an embodiment of the present invention is shown; Figure 10 A trade-off curve diagram based on aluminum under the EMEO track in an embodiment of the present invention is shown; Figure 11 A partial enlarged view of a trade-off curve diagram based on aluminum under the EMEO track in an embodiment of the present invention is shown; Figure 12 shows a trade-off curve diagram under MEO orbit in an embodiment of the present invention; Figure 13 FIG. 4 shows a trade-off curve diagram under the GEO orbit in an embodiment of the present invention.

[0021] Description of reference numerals: 1. Homogeneous composite material sheet; 2. Silicon dosage sheet. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0024] Throughout this specification, references to the terms "embodiment," "one embodiment," and "an implementation" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or implementation are included in at least one embodiment or implementation of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or implementations.

[0025] An embodiment of the present invention provides a homogeneous composite material, comprising 10-30% by mass of epoxy resin, 10-90% by mass of bismuth trioxide, and the remainder being equal in mass fractions of polyethylene and boron nitride.

[0026] In practical applications of this embodiment, epoxy resin is used as a base material (liquid), and polyethylene (PE), hexagonal boron nitride (BN), and bismuth trioxide (Bi2O3) (the latter three are powders) are doped to form a homogeneous composite material. By adding the Bi element, the shielding effectiveness against high-energy electrons in the space radiation environment is increased. By adding polyethylene, etc., the shielding effectiveness against positive-charged high-energy radiation ions such as protons in the space radiation environment can be increased. As a result, the radiation resistance of the homogeneous composite material against different radiation particles in different orbital environments (such as when used as a protective material for spacecraft) can be improved. By adjusting the mass fraction of bismuth trioxide, the overall weight of the protective material can be changed, so that the protective material for spacecraft has both radiation resistance and light weight.

[0027] An embodiment of the present invention further provides a composite material system, comprising a plurality of the homogeneous composite materials as described above, wherein each of the homogeneous composite materials has a different density.

[0028] When this embodiment is applied in practice, by adjusting the mass fraction of bismuth trioxide through a variety of homogeneous composite materials as in the above embodiment, a homogeneous composite material with different densities can be obtained. Since the density of each homogeneous composite material is different, the composite material system includes different density systems, which are specifically manifested as different Bi2O3. The performance of different homogeneous composite materials in the composite material system is different. This difference can be used for the optimization of radiation protection materials.

[0029] In a preferred embodiment, the mass fraction of the epoxy resin is 10%, and the mass fraction of the bismuth trioxide is 90%.

[0030] In a preferred embodiment, the mass fraction of the epoxy resin is 30%, the mass fraction of the bismuth trioxide is 10-70%, and the mass fractions of the polyethylene and the boron nitride are 0-30%.

[0031] Seven preferred materials are given below, as shown in Table 1.

[0032] Table 1

[0033] An embodiment of the present invention also proposes a stacking structure, including any homogeneous composite material in the composite material system described above, and also including a radiation target material. The stacking structure is a flat plate geometric structure, and the homogeneous composite material and the radiation target material are both configured in sheet form and alternately stacked to form the flat plate geometric structure.

[0034] When this embodiment is applied in practice, silicon can be selected as the radiation target material based on the material of the aerospace electronic components, and a flat plate geometric structure of alternating stacks of homogeneous composite materials and thin silicon wafers (i.e., silicon dose wafers) can be set. For different stacking structures, the mass thickness is determined by the density and thickness of the homogeneous composite material. The target material is a thin slice, and the thickness is not taken into account. In this way, multiple stacking structures with different mass thicknesses are established, which can be used to simulate the radiation of radiation particles on the radiation target material under different energy distribution and orbital conditions. The optimal composite material under different energy distribution and orbital conditions can be screened based on the radiation shielding effect of the homogeneous composite material in the stacking structure.

[0035] The following is a method for preparing a homogeneous composite material. Using any of the mass fractions of the above examples, epoxy resin is used as a base material (liquid), doped with polyethylene (PE), hexagonal boron nitride (BN), and bismuth trioxide (Bi2O3) (the latter three are powders), stirred evenly, and applied to cure to obtain a thin sheet of the homogeneous composite material.

[0036] like Figure 2 As shown, an embodiment of the present invention further provides a radiation protection material design method based on the stacking structure described above, comprising: S100: establishing a plurality of stacking structures of different mass thicknesses, wherein each stacking structure of different mass thicknesses comprises a plurality of homogeneous composite materials of different densities.

[0037] Specifically, the density of each homogeneous composite material is certain, and the mass thickness is a parameter of the material, which is defined as the surface density of the material, that is, the mass per unit area. , represents the material density, It represents the (total) thickness of the material. Therefore, under the condition of determining the (fixed) mass thickness, the total thickness of the homogeneous composite material can be calculated. Then, a stacked structure can be obtained by alternately stacking a single piece of homogeneous composite material (sheet) and a radiation target material. At each mass thickness, there are multiple types of homogeneous composite materials. For example, using No.1-No.7 with a mass thickness of 0.1mm, 7 stacked structures are formed.

[0038] S200: Determine the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position.

[0039] Specifically, spacecraft have corresponding on-orbit spatial positions in typical space mission scenarios such as low Earth orbit (LEO), medium Earth orbit (MEO), geostationary orbit (GEO), low polar orbit (LPEO) and equatorial medium Earth orbit (EMEO). By inputting the on-orbit spatial position of the spacecraft into the space radiation environment model, the spacecraft radiation environment energy spectrum, that is, the energy distribution of particle sources in the radiation environment, can be obtained. The space radiation sources that contribute significantly to the on-orbit TID of the spacecraft include radiation belt electrons, radiation belt protons and solar high-energy protons. Different radiation sources require different space radiation environment models.

[0040] S300: performing forward Monte Carlo simulation based on the multiple stacking structures and the spacecraft radiation environment energy spectrum, and counting the total ionizing dose of the last layer of radiation target material of each stacking structure away from the particle source under different orbits according to the number of random particles running.

[0041] Specifically, through forward Monte Carlo simulation, based on a variety of stacking structures and energy distributions, the total ionizing dose (TID) of the last layer of radiation target material away from the particle source under different orbits was statistically analyzed. The TID value is closely related to the number of particles running, the geometric configuration of the stacking structure, and the energy distribution. When high-energy particles pass through the stacking structure, the TID of the last layer of target material accumulates significantly due to multiple scattering and energy deposition. Under different orbital conditions, the differences in the incident angle and flux of the particles further affect the distribution of TID. The size of the TID dose is used to evaluate the shielding effect of the protective material. The smaller the TID, the better the shielding effect. This structure provides a quantitative basis for radiation protection and device reliability design.

[0042] S400: establishing a trade-off curve based on aluminum of the same mass thickness under different orbits according to the total ionizing dose of each stacked structure under different orbits, and screening the homogeneous composite material suitable for the spacecraft operating under different orbits according to the trade-off curve.

[0043] Specifically, homogeneous composite materials of different mass thicknesses are simulated under different tracks, and the experimental results are represented by curves to obtain the relationship between the equivalent aluminum thickness or the mass thickness and the total ionization amount, thereby obtaining the trade-off curve. The mass thickness is measured in Al, and different materials are often converted into equivalent aluminum thickness {mm (Al)} in engineering. The trade-off curve is, for example Figure 6As shown by the middle blue dotted line, for materials selected with the same TID threshold, the TID behind the 1.6mm (Al) thick Al shielding layer is 5605rad (Si), while for the 1.4mm (Al) thick No4 shielding layer, the TID is 5333rad (Si), which means that the radiation protection performance of No4 is 4.9% higher than that of Al, while its mass is 12.5% lower than that of Al. Therefore, a homogeneous composite material designed with the best material system can be selected to achieve the same (or even better) radiation shielding effect as aluminum, and a radiation protection material with a lower mass thickness, that is, a lighter weight.

[0044] When this embodiment is applied in practice, by establishing a stacking structure corresponding to each density of homogeneous composite materials at different mass thicknesses, the on-orbit spatial position of the spacecraft is input into the space radiation environment model to obtain the spacecraft radiation environment energy spectrum, which is used to simulate the radiation effects of radiation belt electrons, radiation belt protons, and solar high-energy protons on the radiation target material under the shielding of the stacking structure, and performing forward Monte Carlo simulation to calculate the total ionizing dose of the last layer of radiation target material of each stacking structure under different orbits. Through realistic simulation under different orbital and energy distribution conditions, a quantitative basis is provided for radiation protection and device reliability design. According to the total ionizing dose of each stacking structure under different orbits, a trade-off curve based on aluminum of the same mass thickness under different orbits is established. Using aluminum as the measurement standard, radiation protection materials with both radiation resistance and composite lightweight requirements can be screened out.

[0045] The above optimization is based on the differences in orbital radiation environment to avoid the imbalance between protection effectiveness and mass ratio, to avoid the inability of monoenergetic particle ground tests to simulate the real space wide energy spectrum radiation environment, and to avoid the design results deviating from actual needs.

[0046] As an optional embodiment of the present invention, the establishing of multiple stacked structures with different mass thicknesses includes: According to the plurality of homogeneous composite materials with different densities, the thickness of the homogeneous composite materials with different densities at the same mass thickness is determined, and thereby the plurality of stacking structures with different mass thicknesses are established.

[0047] Specifically, a flat plate geometry structure is set up in which homogeneous composite material sheets 1 and silicon dosage sheets 2 (i.e., 100 μm-1 mm thin silicon dosage sheets) are alternately stacked. For different stacking structures, the mass thickness is determined by the density and thickness of the homogeneous composite material. The density and mass thickness of each homogeneous composite material are known. According to the material density ( , g / cm3) to set the geometric thickness to obtain the same mass thickness (g / cm2, also known as surface mass, which represents the weight of the material per unit area), expressed as ; Calculate the thickness of the homogeneous composite material from this Generally, the thickness of the homogeneous composite material at the minimum mass thickness is calculated first, such as 0.2 mm, and then it can be stacked in equal multiples. The target material is taken as a thin slice and the thickness is not included in the thickness, thereby establishing a variety of stacking structures with different mass thicknesses.

[0048] As an optional embodiment of the present invention, determining the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position includes: determining various orbital parameters of the spacecraft using a spacecraft orbit extrapolation model, wherein the orbital parameters include orbit type, perigee distance, apogee distance, and orbit inclination; Specifically, five typical orbital parameters with real application value are selected to characterize the on-orbit space radiation environment, as shown in Table 2.

[0049] Table 2

[0050] The multiple orbital parameters are input into a space radiation environment model to determine the spacecraft radiation environment energy spectrum. The space radiation environment model includes a radiation belt electron environment model, a radiation belt proton environment model, and a solar high-energy proton environment model.

[0051] Specifically, the space radiation environment characterization model calculates the energy spectrum of a typical orbital radiation environment: Radiation belt electronic environment: AE9 model; Radiation belt proton environment: AP9 model; Solar high-energy proton environment: SAPPHIRE model; Substitute the position of the spacecraft in different orbits into the space radiation environment characterization model (a mature simulation model), and calculate the flux of radiation particles (radiation electrons, radiation protons and solar long-term protons) under the condition of constant energy. By obtaining the average of the flux at a certain energy, the environmental energy spectrum can be obtained.

[0052] Specifically, the radiation environment in low-Earth orbit is extremely complex and is affected by the coupling of multiple factors, resulting in radiation environments with huge differences in different orbits. Specific influencing factors include: (1) Space radiation sources: The space radiation sources that contribute most to spacecraft TID on orbit include radiation belt electrons, radiation belt protons, and solar high-energy protons. Space radiation sources have a wide energy spectrum, that is, the flux of particles of different energies varies with the energy of the particles. Generally speaking, the higher the energy, the lower the flux.

[0053] (2) Distribution of space radiation sources: The space radiation environment from different sources is unevenly distributed in near-Earth space. The Earth's radiation belts are mainly distributed in two annular belts at different altitudes, the inner and outer belts centered on the geomagnetic dipole axis. The inner belt extends from a few hundred kilometers to an altitude of 6,000 km above the equator and is mainly composed of high-energy protons and high-energy electrons. The outer belt can extend to an altitude of 60,000 km and is mainly composed of high-energy electrons. The solar high-energy proton radiation is mainly modulated by the geomagnetic field and is affected by the geomagnetic shielding effect. It can only reach low-Earth orbit in the polar regions or when the particle energy is high enough.

[0054] The orbit of a spacecraft in space is controlled by orbital parameters such as perigee, apogee, and inclination. As it passes through different areas in space, it couples with the characteristics of space radiation sources, resulting in huge differences in the radiation environment energy spectrum of different orbits. The radiation environment energy spectrum is determined below.

[0055] like Figure 3 As shown in the simulation of the radiation belt electron environment using the 95% AE9 model, the electron environment in GEO is two orders of magnitude higher than that in LEO. When the electron energy approaches 10 MeV, the electron flux in MEO and GEO is similar, and is more than three orders of magnitude higher than that in LEO. The LPEO orbital electron energy spectrum is similar to but slightly higher than that of LEO. The EMEO radiation belt electron energy spectrum is significantly different from other orbits. When the electron energy is below 1 MeV, its flux is higher than that of other orbits, and when the electron energy is above 1 MeV, its flux drops rapidly. like Figure 4 As shown in the figure, for the simulation of the proton environment in the radiation belt, the AP9 model with a 95% percentage mode is used. The proton energy spectrum in MEO and GEO does not exceed 10 MeV, while the proton energy spectrum in LEO, LPEO and EMEO is as high as 10 3 MeV.

[0056] like Figure 5 As shown, during periods of solar activity, the SAPPHIRE model simulates the long-term solar proton environment with a 95% confidence level, taking into account the geomagnetic cutoff stiffness during periods of geomagnetic quiet. The proton energy spectrum in MEO is similar to, but slightly lower than, that in GEO. Due to the strong geomagnetic shielding effect, only a small number of high-energy protons are present in LEO, and no solar protons are present in EMEO. Because the LPEO orbit passes over the Earth's polar regions, it is affected by the solar proton environment distributed in these polar regions.

[0057] As an optional embodiment of the present invention, the forward Monte Carlo simulation is performed based on the multiple stacked structures and the spacecraft radiation environment energy spectrum, and according to the number of random particles running, the total ionizing dose of the last layer of radiation target material of each stacked structure away from the particle source under different orbits is calculated, including: A square surface source, a distance between the particle source and the stacked structure, and a radiation emission direction are determined based on the particle source that conforms to the spacecraft radiation environment energy spectrum, and a forward Monte Carlo simulation is performed to calculate the total ionizing dose. The radiation target material includes a silicon dose sheet.

[0058] Specifically, after determining the energy spectrum of the on-orbit radiation environment and setting the particle source energy distribution, the particle source is set as a square surface source (simulating the coverage of the space environment on the spacecraft) and placed at a preset distance above the sample (stacked structure). The emission direction of the particle source is set to the spatial isotropic particle source mode (to ensure that the sample surface can be radiated from all directions. The arrows in Figure 1 indicate the various directions of particle source radiation, generally 0-180 degrees). Silicon dose sheets are used as radiation targets, which are more in line with the actual material structure of the spacecraft. Figure 1 The forward Monte Carlo simulation shown covers the following physical processes: electromagnetic processes, hadronic interactions, decay processes, gamma-nuclear and light-nuclear processes, optical photon processes, parameter processes and transport processes, and performs total ionization dose, realistically simulating the process of spacecraft being irradiated by particles in different orbital environments.

[0059] As an optional embodiment of the present invention, establishing a trade-off curve based on the total ionizing dose of each stacked structure under different orbits with aluminum of the same mass thickness as a benchmark under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve includes: The mass thickness is converted into an equivalent aluminum thickness, and the trade-off curve is constructed according to the relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks.

[0060] Specifically, after calculating the stacking structures with different mass thicknesses, the mass thickness of the stacking structure is equal to the mass thickness of the homogeneous composite material it constitutes, and the mass thickness of the 1 mm thick aluminum material is equal to the mass thickness of the 1 mm thick aluminum material. .

[0061] When this embodiment is applied in practice, homogeneous composite materials of different mass thicknesses are subjected to simulation experiments under different tracks, and the experimental results are represented by a curve to obtain the relationship between the equivalent aluminum thickness or the mass thickness and the total ionization amount, and to obtain the trade-off curve, for example Figure 6 As shown, the trade-off curve is used for the optimization screening design of homogeneous composite materials.

[0062] like Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 and Figure 13 As shown, as an optional embodiment of the present invention, converting the mass thickness into an equivalent aluminum thickness, and constructing the trade-off curve according to the relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks includes: Based on a low earth orbit, a near polar orbit, and an equatorial medium earth orbit, a corresponding relationship between the total ionizing dose and the equivalent aluminum thickness of each stacked structure is established, and a first trade-off curve is constructed.

[0063] Based on the medium earth orbit and the geostationary orbit, a corresponding relationship between the total ionizing dose and the mass thickness of each stacked structure is established, and a second trade-off curve is constructed.

[0064] Therein, the stacked structures are marked by corresponding homogeneous composite materials.

[0065] For example, the orbits covered by the first trade-off curve include LEO orbit (low earth orbit), LPEO orbit (low polar orbit), and EMEO orbit (equatorial medium earth orbit), such as Figure 6 、 Figure 7 、 Figure 8 and Figure 9 、 Figure 10 and Figure 11 As shown in (the horizontal axis is the total ionizing dose, the vertical axis is the equivalent aluminum thickness), the orbits covered by the second trade-off curve include MEO (Medium Earth Orbit) and GEO orbit (Geostationary Orbit), such as Figure 12 and Figure 13 As shown (the horizontal axis is mass thickness, and the vertical axis is total ionizing dose).

[0066] Specifically, the first trade-off curve and the second trade-off curve are essentially curves of the same nature. After the mass thickness in the second trade-off curve is converted into equivalent aluminum thickness, a curve of the same type as the first trade-off curve can be obtained. Different homogeneous composite materials correspond to corresponding stacking structures and are marked with homogeneous composite materials No. 1-No. 7. The same mass thickness or equivalent aluminum thickness is connected into a line, and Al and W are added for comparison. This can be used to compare the performance of homogeneous composite materials under different TIDs and different mass thicknesses.

[0067] like Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 and Figure 13 As shown, an embodiment of the present invention further provides a method of establishing a trade-off curve based on the total ionizing dose of each stacked structure under different orbits and taking aluminum of the same mass thickness as a benchmark under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve, including: Determining, according to the first trade-off curve, the stacking structure corresponding to the minimum total ionizing dose at the same equivalent aluminum thickness, and determining the corresponding homogeneous composite material; Specifically, in LEO orbit, based on Figure 6 and Figure 7 , we can find the optimal material system for different types of materials under the same equivalent aluminum thickness, and we can also find lighter homogeneous composite materials with the same shielding effect based on this figure, that is, with the increase of mass thickness, the shielding performance of No.7 material transitions from the best to the fifth, that is, at an equivalent thickness of 0.2mm (Al), the TID value of No.7 is the lowest, indicating that No.7 has the best shielding performance. When the equivalent thickness increases to 2.0mm (Al), the TID result of No.7 becomes the fifth from the bottom. As the equivalent thickness increases, the material with the best shielding performance shifts from No.7 to No.5. Figure 6 and Figure 7 In the results, the homogeneous composite material can reduce the TID result to up to 58% of that of aluminum at the same equivalent aluminum thickness, at 2 mm (Al) equivalent thickness.

[0068] Under the LEPO orbit, such as Figure 8 and Figure 9 As shown, it is possible to identify optimal material systems for different types of materials at the same equivalent aluminum thickness. This figure also allows for the identification of lighter homogeneous composite materials with the same shielding effectiveness. As the equivalent thickness increases, the shielding performance of material No. 7 gradually transitions from the best to the worst. As the equivalent thickness increases, the best shielding performance material shifts from No. 7 to No. 1. At the same equivalent aluminum thickness, homogeneous composite materials can reduce TID by up to 64% compared to aluminum, at an equivalent thickness of 0.6 mm (Al).

[0069] Under the EMO track, such as Figure 10 and Figure 11As shown, the optimal material system for different types of materials at the same equivalent aluminum thickness can be found. This figure also identifies lighter homogeneous composite materials with the same shielding effectiveness. As the equivalent thickness increases, the shielding performance of material No. 6 gradually transitions from the best to the sixth. As the equivalent thickness increases, the best shielding performance material shifts from No. 6 to No. 1. At the same equivalent aluminum thickness, homogeneous composite materials can reduce TID by up to 67% compared to aluminum, at an equivalent thickness of 0.4 mm (Al).

[0070] According to the second trade-off curve, the stacking structure corresponding to the minimum mass thickness under the total ionizing dose of the same level is determined, and the corresponding homogeneous composite material is determined.

[0071] Specifically, in MEO and GEO orbit missions, the high-energy electron flux is large, and the electron environment is more severe than the proton environment. Figure 12 and Figure 13 It can be seen that as the thickness on the horizontal axis increases, the TID gradually decreases, that is, the electron TID contribution dominates from thinner mass thickness to thicker mass thickness. Therefore, the shielding effect of the homogeneous composite material in the figure is always manifested as a shielding effect for electrons. That is, composite materials with high Bi2O3 content, such as No. 7 and No. 6, have the best shielding effect. Looking vertically along the vertical axis, it is possible to screen out the materials corresponding to the lowest TID at the same mass thickness (such as No. 7 and No. 6). Looking horizontally along the horizontal axis, it is possible to screen out the homogeneous composite material corresponding to the smallest mass thickness at the same level of total ionizing dose (the closer to the left, the lower the weight), that is, materials that meet radiation protection requirements and are lighter, so as to take into account the needs of radiation resistance and light weight.

[0072] Example 1 Homogeneous composite materials numbered No. 1-No. 7 in Table 1, as well as pure aluminum (Al) and pure tungsten (W) materials, were used as equivalent aluminum thicknesses from 0.2 to 2.0 mm, with uniform intervals of 0.2 mm. Stacked structures with the same mass thickness were constructed. Experiments were conducted in the radiation belt electron environment, the radiation belt proton environment, and the low Earth orbit (LEO) environment of the sun's high-energy protons, and the total ionizing dose (TID) of the last layer of the radiation target was measured.

[0073] The experimental results show that as the thickness increases, the shielding performance of No.7 material transitions from the best to the fifth. That is, at an equivalent thickness of 0.2mm (Al), the TID value of No.7 is the lowest, indicating that No.7 has the best shielding performance. When the equivalent thickness increases to 2.0mm (Al), the TID result of No.7 becomes the fifth from the bottom. As the equivalent thickness increases, the material with the best shielding performance shifts from No.7 to No.5. Figure 6 and with Figure 7 In the results, the homogeneous composite material can reduce the TID result to up to 58% of that of aluminum at the same equivalent aluminum thickness, at 2 mm (Al) equivalent thickness.

[0074] Example 2 Homogeneous composite materials numbered No. 1-No. 7 in Table 1, as well as pure aluminum (Al) and pure tungsten (W) materials, were used as equivalent aluminum thicknesses from 0.2 to 2.0 mm, with uniform intervals of 0.2 mm. Stacked structures with the same mass and thickness were constructed. Experiments were conducted in the radiation belt electron environment, the radiation belt proton environment, and the low-Earth polar orbit (LPEO) environment in the solar high-energy proton environment, and the total ionizing dose (TID) of the last layer of radiation target material was measured.

[0075] The experimental results show that as the equivalent thickness increases, the shielding performance of No.7 material gradually transitions from the best to the worst. As the equivalent thickness increases, the material with the best shielding effect changes from No.7 to No.1. Figure 8 and with Figure 9 In the study, at the same equivalent aluminum thickness, the homogeneous composite material can reduce the TID by up to 64% compared to aluminum, at an equivalent thickness of 0.6 mm (Al).

[0076] Example 3 Homogeneous composite materials numbered No. 1-No. 7 in Table 1, as well as pure aluminum (Al) and pure tungsten (W) materials, were used as equivalent aluminum thicknesses from 0.2 to 2.0 mm, with uniform intervals of 0.2 mm. Stacked structures with the same mass thickness were constructed. Experiments were conducted in the radiation belt electron environment, the radiation belt proton environment, and the equatorial medium Earth orbit (EMEO) environment in the solar high-energy proton environment, and the total ionizing dose (TID) of the last layer of radiation target material was measured.

[0077] The experimental results show that as the equivalent thickness increases, the shielding performance of No.6 material gradually transitions from the best to No.6. As the equivalent thickness increases, the material with the best shielding effect changes from No.6 to No.1. Figure 10 and with Figure 11 In the study, at the same equivalent aluminum thickness, the homogeneous composite material can reduce the TID by up to 67% compared to aluminum, at an equivalent thickness of 0.4 mm (Al).

[0078] Example 4 Homogeneous composite materials numbered No. 1-No. 7 in Table 1, as well as pure aluminum (Al) materials and pure tungsten (W) materials, were used as mass thicknesses ranging from 0.1 to 0.6 mm with uniform intervals of 0.1 mm to construct stacked structures with the same mass thickness. Experiments were carried out in the medium Earth orbit (MEO) under the radiation belt electron environment, the radiation belt proton environment, and the solar high-energy proton environment, and the total ionizing dose (TID) of the last layer of radiation target material was measured.

[0079] The experimental results show that due to the large high-energy electron flux in the MEO orbit mission and the harsher electron environment compared to the proton environment, the electron TID contribution dominates from thinner mass thickness to thicker mass thickness. Figure 12 The shielding effect of the medium-homogeneous composite materials is always manifested as a shielding effect against electrons, that is, the composite materials with high Bi2O3 content, such as No.7 and No.6, have the best shielding effect.

[0080] Example 5 Homogeneous composite materials numbered No. 1-No. 7 in Table 1, as well as pure aluminum (Al) and pure tungsten (W) materials, were used as mass thicknesses ranging from 0.1 to 0.6 mm, with uniform intervals of 0.1 mm. Stacked structures with the same mass thickness were constructed. Experiments were conducted in the geostationary orbit (GEO) under the radiation belt electron environment, the radiation belt proton environment, and the solar high-energy proton environment, and the total ionizing dose (TID) of the last layer of radiation target material was measured.

[0081] The experimental results show that due to the large high-energy electron flux in the GEO orbital mission and the harsher electron environment compared to the proton environment, the electron TID contribution dominates from thinner mass thickness to thicker mass thickness. Figure 13 The shielding effect of the medium-homogeneous composite materials is always manifested as a shielding effect against electrons, that is, the composite materials with high Bi2O3 content, such as No.7 and No.6, have the best shielding effect.

[0082] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

[0083] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A homogeneous composite material, characterized in that The invention comprises epoxy resin with a mass fraction of 10-30%, bismuth trioxide with a mass fraction of 10-90%, and the rest being polyethylene and boron nitride with equal mass fractions.

2. A composite material system, characterized in that: The method comprises a plurality of homogeneous composite materials as claimed in claim 1, wherein each of the homogeneous composite materials has a different density.

3. A stacking structure, characterized in that: It includes any homogeneous composite material in the composite material system as described in claim 2, and also includes a radiation target material. The stacking structure is a flat plate geometric structure. The homogeneous composite material and the radiation target material are both configured as sheets and alternately stacked to form the flat plate geometric structure.

4. A method for designing radiation protection materials, characterized in that: Based on the stacking structure according to claim 3, comprising: Establishing a plurality of stacked structures of different mass thicknesses, wherein each stacked structure of different mass thicknesses comprises a plurality of homogeneous composite materials of different densities; Determine the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position; Performing forward Monte Carlo simulation based on the multiple stacking structures and the spacecraft radiation environment energy spectra, and calculating the total ionizing dose of the last layer of radiation target material of each stacking structure away from the particle source under different orbits according to the number of random particle movements; According to the total ionizing dose of each stacked structure under different orbits, a trade-off curve based on aluminum of the same mass thickness under different orbits is established, and the homogeneous composite material suitable for the operation of the spacecraft under different orbits is screened according to the trade-off curve.

5. The radiation protection material design method according to claim 4, characterized in that: The establishing of a plurality of stacked structures with different mass thicknesses comprises: According to the plurality of homogeneous composite materials with different densities, the thickness of the homogeneous composite materials with different densities at the same mass thickness is determined, and thereby the plurality of stacking structures with different mass thicknesses are established.

6. The radiation protection material design method according to claim 4, characterized in that: Determining the spacecraft radiation environment energy spectrum based on the space radiation environment model and the spacecraft's on-orbit spatial position includes: determining various orbital parameters of the spacecraft using a spacecraft orbit extrapolation model, wherein the orbital parameters include orbit type, perigee distance, apogee distance, and orbit inclination; The plurality of orbital parameters are input into a space radiation environment model to determine the spacecraft radiation environment energy spectrum, wherein the space radiation environment model includes a radiation belt electron environment model, a radiation belt proton environment model, and a solar high-energy proton environment model.

7. The radiation protection material design method according to claim 6, characterized in that: The forward Monte Carlo simulation is performed based on the multiple stacking structures and the spacecraft radiation environment energy spectrum, and according to the number of random particles running, the total ionizing dose of the last layer of radiation target material of each stacking structure away from the particle source under different orbits is calculated, including: A square surface source, a distance between the particle source and the stacked structure, and a radiation emission direction are determined based on the particle source that conforms to the spacecraft radiation environment energy spectrum, and a forward Monte Carlo simulation is performed to calculate the total ionizing dose, wherein the radiation target material includes a silicon dose sheet.

8. The method for designing radiation protection materials according to any one of claims 4 to 7, characterized in that: The step of establishing a trade-off curve based on aluminum of the same mass and thickness under different orbits according to the total ionizing dose of each stacked structure under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve includes: The mass thickness is converted into an equivalent aluminum thickness, and the trade-off curve is constructed according to the relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks.

9. The method for designing radiation protection materials according to claim 8, characterized in that: The converting the mass thickness into an equivalent aluminum thickness, and constructing the trade-off curve according to the relationship between the equivalent aluminum thickness or the mass thickness and the total ionizing dose of each stacked structure under different tracks includes: Based on a low earth orbit, a near polar orbit, and an equatorial medium earth orbit, establishing a corresponding relationship between the total ionizing dose and the equivalent aluminum thickness of each stacked structure, and constructing a first trade-off curve; Based on a medium earth orbit and a geostationary orbit, establishing a corresponding relationship between the total ionizing dose and the mass thickness of each stacked structure, and constructing a second trade-off curve; Wherein, the stacked structure is marked by the corresponding homogeneous composite material.

10. The radiation protection material design method according to claim 9, characterized in that: The step of establishing a trade-off curve based on aluminum of the same mass and thickness under different orbits according to the total ionizing dose of each stacked structure under different orbits, and screening the homogeneous composite material suitable for spacecraft operation under different orbits according to the trade-off curve includes: Determining, according to the first trade-off curve, the stacking structure corresponding to the minimum total ionizing dose at the same equivalent aluminum thickness, and determining the corresponding homogeneous composite material; According to the second trade-off curve, the stacking structure corresponding to the minimum mass thickness under the total ionizing dose of the same level is determined, and the corresponding homogeneous composite material is determined.

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