A method for determining a damage threshold of a thermal control multilayer
By dividing the thermal control multi-layer target damage images and external heat flux power density distribution maps into grids, the damage probability can be judged and calculated, solving the problem of accurately determining the thermal control multi-layer damage threshold, realizing efficient assessment and data utilization, and supporting the thermal control protection of spacecraft.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINESE PEOPLES LIBERATION ARMY UNIT 32027
- Filing Date
- 2023-03-03
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies make it difficult to accurately determine the damage threshold of the thermal control layers of spacecraft, and the experimental data cannot be fully utilized due to differences in external heat flow caused by irradiation, resulting in high costs and insufficient sample size.
By dividing the thermally controlled multilayer target damage image and external heat flux power density distribution map into an N×N grid, the damage state of each grid cell is determined and the average power density is calculated. The damage probability under different average power densities is statistically analyzed to determine the damage threshold power density.
It enables accurate assessment of the damage threshold of thermal control multilayers with a limited number of tests, avoids insufficient data utilization due to differences in external heat flux caused by irradiation, and provides a protective basis for thermal control multilayers of spacecraft.
Smart Images
Figure CN116187072B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of radiation effect technology, and in particular to a method for determining the damage threshold of thermally controlled multilayers. Background Technology
[0002] Spacecraft primarily rely on thermal control systems to ensure that the internal temperature of the satellite meets operational requirements. The thermal control multilayer is composed of alternating layers of low-emissivity reflective screens and low-thermal-conductivity spacers. Utilizing the layered reflection of these screens, it creates high thermal resistance to radiative heat flow, providing excellent thermal insulation performance under vacuum conditions, making it one of the most fundamental thermal control methods for spacecraft. As an exposed component of the spacecraft, the thermal control multilayer has a large area and is easily affected by external heat flow. Severe damage or even destruction of the thermal control multilayer can significantly impact its thermal insulation and temperature control capabilities, potentially leading to a decrease or even loss of the spacecraft's temperature regulation function.
[0003] To improve the protection capabilities of thermal control multilayers in spacecraft, a primary key issue is determining the damage threshold of these multilayers under different external heat fluxes. There are generally two definitions of the damage threshold: one is the traditional method using a rise-fall approach, where the average of the maximum energy density value that does not cause damage and the minimum energy density value that causes damage is taken as the damage threshold, corresponding to a 50% probability of damage; the other is the energy density value corresponding to a zero probability of damage. Regardless of the definition, extensive equivalent experiments must be conducted on the ground. However, practical problems such as differences in external heat flux, high experimental costs, and insufficient data sample size make it difficult to accurately determine the damage threshold.
[0004] Therefore, it is necessary to study and propose a method for determining the damage threshold of thermal control multilayers under external heat flow irradiation. This method should avoid the drawback of not being able to fully utilize experimental data due to differences in external heat flow, and should be able to evaluate and give the damage threshold of thermal control multilayers through a small number of experiments, thus laying the foundation for the protection research of thermal control multilayers in spacecraft. Summary of the Invention
[0005] The purpose of this invention is to provide a method for determining the damage threshold of thermally controlled multilayers, so as to effectively avoid the drawback of not being able to fully utilize experimental data due to differences in external heat flow caused by irradiation, and to evaluate and give the damage threshold of thermally controlled multilayers through a small number of experiments.
[0006] In a first aspect, this application provides a method for determining the damage threshold of a thermally controlled multilayer target, comprising the following steps: determining a damage image of a thermally controlled multilayer target and a heat flux power density distribution map outside the target surface; dividing the entire target surface into N×N grids of the same scale according to the damage image of the thermally controlled multilayer target and the heat flux power density distribution map outside the target surface to obtain N... 2The grid cells consist of a thermally controlled multilayer target damage image, which is a frontal image of the damage morphology of the thermally controlled multilayer after the test, used to determine the damage state within the grid cells; and an external heat flux power density distribution map, which is a power density distribution map of the surface of the thermally controlled multilayer target during the test, used to calculate the average power density within the grid cells.
[0007] Determine the damage status of each grid cell, including damaged and undamaged states;
[0008] Calculate the average power density for each grid cell;
[0009] Determine the damage probability corresponding to different average power densities, and accordingly, determine the threshold power density of the thermal control multilayer under different damage probabilities.
[0010] Using the above technical solution, the thermally controlled multi-layer target damage image and the target surface external heat flux power density distribution map are divided into N... 2 The process involves dividing the system into grid cells, determining the damage state of each cell, and calculating the corresponding average power density. Based on this, the damage state at each average power density can be accurately determined. Further statistical analysis is used to determine the damage probability at different average power densities. Correspondingly, the threshold power density for the thermal control multilayer is finally determined for different damage probabilities. The threshold power density value represents the threshold corresponding to different damage probabilities. As can be seen from the above process, grid-based division effectively avoids the drawback of insufficient experimental data due to differences in external irradiation heat flux. In other words, only a limited number of experiments are needed to evaluate and provide the damage threshold for the thermal control multilayer. Therefore, this lays the foundation for research on the protection of thermal control multilayers in spacecraft.
[0011] As one possible implementation, the format of thermally controlled multi-layer target damage images includes any one of the following formats: jpg, jpeg, bmp, or png.
[0012] As one possible implementation, the thermally controlled multilayer target damage image is a frontal image of the damage morphology of the thermally controlled multilayer.
[0013] As one possible implementation, N is an integer greater than or equal to 10.
[0014] As one possible implementation, determining the damage state of each grid cell includes: using observation methods to determine the damage state of each grid cell.
[0015] As one possible implementation, determining the damage status of each grid cell includes: generating a binary image based on the damage image of the thermally controlled multi-layer target, where the pixel values of the binary image are 0 and 1, where 1 represents damage and 0 represents no damage; performing the same grid division on the binary image and the external heat flux power density distribution map; when determining the damage status of a grid cell, by statistically summing the pixel values of the binary image within the grid cell region, if the sum exceeds half of the total number of image pixels within a grid region, it is determined to be damaged, and the grid status is marked as 1; otherwise, it is marked as 0.
[0016] As one possible implementation, the average power density corresponding to each of the grid cells is calculated, including:
[0017] The heat flux power density distribution map outside the target surface is divided into N×N sub-images according to the grid.
[0018] The average value of the pixels in each sub-image is used as the average power density of that grid cell.
[0019] As one possible approach, the damage probability corresponding to different average power densities is determined by: statistically analyzing the thermally controlled multilayer damage state and average power density on each grid cell, and obtaining the ratio of the number of damaged cells to the total number of cells under different power densities, i.e., the damage probability.
[0020] The statistical analysis of the thermally controlled multilayer damage state and average power density on each grid cell yields the ratio of the number of damaged cells to the total number of cells under different power densities, i.e., the damage probability, including:
[0021] Based on the average power density and damage state of each grid cell, N is obtained. 2 One data point pair;
[0022] The total number of elements and the number of damaged elements in different power density intervals were obtained based on interval statistics.
[0023] The damage probability corresponding to different average power density ranges is determined by the ratio of the number of damaged units to the total number of units.
[0024] As one possible implementation, the external heat flux power density distribution map is a two-dimensional matrix power density distribution map corresponding to the thermally controlled multilayer target damage image. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some examples of this application. For those skilled in the art, other drawings can be obtained based on these drawings, without exceeding the scope of protection claimed by this application.
[0026] Figure 1 This is a flowchart of the method for determining the damage threshold of thermally controlled multilayer structures provided in this embodiment of the invention;
[0027] Figure 2 This is a schematic diagram of the gridded structure provided in an embodiment of the present invention;
[0028] Figure 3 These are thermally controlled multi-layer target damage images provided in embodiments of the present invention;
[0029] Figure 4 This is a schematic diagram of the damage probability curve provided in an embodiment of the present invention. Detailed Implementation
[0030] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0031] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.
[0033] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0035] Reference Figure 1 The method for determining the damage threshold of thermally controlled multilayer structures provided in this embodiment of the invention includes the following steps:
[0036] S10. Provide damage images of thermally controlled multi-layered targets and heat flux power density distribution maps outside the target surface. Divide the entire target surface into N×N grids of the same scale to obtain N... 2 Each grid cell.
[0037] See Figure 2 and Figure 3 The aforementioned thermally controlled multilayer target damage images and external heat flux power density distribution maps were obtained through damage experiments. Specifically, the thermally controlled multilayer target damage images were obtained by photographing the multilayer morphology after the experiment, and the external heat flux power density distribution maps were obtained by measuring the external heat flux from the irradiation. The thermally controlled multilayer target damage images can be in any of the following formats: JPG, JPEG, BMP, or PNG, without specific limitations. To facilitate the determination of the damage state, the thermally controlled multilayer target damage images are frontal images of the damaged morphology of the thermally controlled multilayer. The external heat flux power density distribution map is a two-dimensional matrix power density distribution map corresponding to the thermally controlled multilayer target damage images.
[0038] After obtaining the thermally controlled multilayer target damage image, a reasonable mesh density can be selected based on the size of the thermally controlled multilayer sample. For example, N=10, in which case a 10×10 mesh element can be created. Specifically, the thermally controlled multilayer damage morphology and its corresponding external heat flux distribution are divided across the entire target surface at the same scale, ultimately forming 100 relatively independent mesh elements. Of course, N can also be 15, 20, or other suitable values.
[0039] S11. Determine the damage status of each grid cell, which includes damaged and undamaged. For example, the damage status of a grid cell can be determined by observation. Specifically, when more than half of the cell's area is damaged, it is considered damaged and the status is marked as 1; otherwise, it is considered undamaged and the status is marked as 0.
[0040] For example, firstly, a binary image is generated based on the thermal control multi-layer target damage image. The pixel values of the binary image are 0 and 1, where 1 represents damage and 0 represents no damage. Secondly, the binary image and the external heat flux power density distribution map are divided into the same grid. Finally, when determining the damage status of a grid cell, the sum of the pixel values of the binary image within the grid cell region is calculated. If the sum exceeds half of the total number of pixels in a grid region, it is determined to be damaged, and the grid status is marked as 1; otherwise, it is marked as 0.
[0041] S12. Calculate the average power density corresponding to each grid cell. For example, firstly, the heat flux power density distribution map outside the target surface is divided into 10×10 sub-images according to the grid. Secondly, the average value of the pixels in the sub-image is used as the average power density corresponding to that grid cell. Finally, the average power density corresponding to each grid cell is obtained one by one.
[0042] S13. Determine the damage probability corresponding to different average power densities. For example, firstly, obtain 100 data point pairs based on the average power density and damage state of each grid cell. Secondly, obtain the total number of cells and the number of damaged cells within different power density intervals based on interval statistics. Finally, determine the damage probability corresponding to different average power density intervals by the ratio of the number of damaged cells to the total number of cells. Accordingly, determine the threshold power density of the thermal control multilayer under different damage probabilities. See [link to relevant documentation] Figure 4 The average power density under a specified damage probability can be obtained through linear interpolation, which serves as the threshold power density for the thermally controlled multilayer at that damage probability. The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for determining the damage threshold of a thermally controlled multilayer structure, characterized in that, Includes the following steps: Determine the damage image and the external heat flux power density distribution map of the thermally controlled multi-layer target, and then process the damage image and the external heat flux power density distribution map according to... The mesh is divided into full target surface segments of the same scale to obtain... Each grid cell contains a thermally controlled multilayer target damage image, which is a frontal image of the damage morphology of the thermally controlled multilayer target after the experiment, used to determine the damage state within the grid cell; the external heat flux power density distribution map is a power density distribution map of the surface irradiated by the thermally controlled multilayer target during the experiment, used to calculate the average power density within the grid cell; the external heat flux power density distribution map is a two-dimensional matrix power density distribution map corresponding to the thermally controlled multilayer target damage image. Determine the damage status of each grid cell, where the damage status includes damaged and undamaged; Calculate the average power density corresponding to each of the grid cells; Determining the damage probability corresponding to different average power densities includes: By statistically analyzing the thermally controlled multilayer damage state and average power density on each grid cell, the ratio of the number of damaged cells to the total number of cells under different power densities is obtained, i.e., the damage probability. The process of statistically analyzing the thermally controlled multilayer damage state and average power density on each grid cell to obtain the ratio of the number of damaged cells to the total number of cells under different power densities, i.e., the damage probability, includes: Based on the average power density and damage state of each grid cell, we obtain One data point pair; The total number of elements and the number of damaged elements in different power density intervals were obtained based on interval statistics. The damage probability corresponding to different average power density ranges is determined by the ratio of the number of damaged units to the total number of units. Accordingly, the threshold power density of the thermal control multilayer is determined under different damage probabilities.
2. The method for determining the damage threshold of a thermally controlled multilayer structure according to claim 1, characterized in that, The thermally controlled multi-layer target damage image can be in any of the following formats: jpeg, bmp, or png.
3. The method for determining the damage threshold of a thermally controlled multilayer structure according to claim 1, characterized in that, N is an integer greater than or equal to 10.
4. The method for determining the damage threshold of a thermally controlled multilayer structure according to claim 1, characterized in that, Determining the damage state of each mesh cell includes: The damage status of each grid cell is determined using observation methods.
5. The method for determining the damage threshold of a thermally controlled multilayer structure according to claim 1, characterized in that, Determining the damage state of each mesh cell includes: A binarized image is generated based on the thermal control multi-layer target damage image. The pixel values of the binarized image are 0 and 1, where 1 represents damage and 0 represents no damage. The binarized image and the external heat flux power density distribution map are subjected to the same grid division; When determining the damage status of a grid cell, the sum of the pixel values of the binarized image within the grid cell region is counted. If the sum exceeds half of the total number of image pixels within a grid cell region, it is determined to be damaged, and the grid status is marked as 1; otherwise, it is marked as 0.
6. The method for determining the damage threshold of a thermally controlled multilayer structure according to claim 1, characterized in that, Calculating the average power density corresponding to each of the grid cells includes: The heat flux power density distribution map outside the target surface is divided into grids. Zhang Zi's picture; The average value of the pixels in each sub-image is used as the average power density of that grid cell.