Method and system for testing sunscreen performance of composite sunscreen thermal insulation material

Abstract

The invention relates to the technical field of material performance testing, in particular to a method and a system for testing the sunscreen performance of a composite sunscreen thermal insulation material. According to a surface temperature field distribution image, a heat distribution disorder index and a heat distribution disorder variable coefficient of the surface of the material are analyzed, and an interface dynamic effect intensity factor of the material is quantified; the influence of thermal resistance and thermal expansion difference on heat conduction stability is accurately evaluated; meanwhile, based on spectral data of all wave bands and surface average temperature data, correlation characteristics of the ultraviolet absorption amount, the heat loss amount and the surface temperature rise rate are analyzed, a photothermal conversion efficiency index is established, the thermal stress accumulation process is tracked in combination with the temperature gradient and the thermal stress history, and performance deviation caused by the cross-scale dynamic effect is revealed; the relation between the dynamic effect and the thermal stress is further analyzed, a real-time compensation value is generated, a traditional static test result is corrected, and therefore system errors caused by photothermal conversion nonlinearity, interface thermal stress accumulation and multi-layer structure anisotropy are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of material performance testing, and particularly relates to a method and system for testing the sun protection performance of a composite sun protection and heat insulation material. Background Art

[0002] A composite sun protection and heat insulation material is a new type of material with dual protection functions, and its core characteristics are high-efficiency shielding of ultraviolet rays and suppression of heat conduction. This material is widely used in fields such as building facades, transportation vehicles, and spacecrafts. By reducing the indoor-outdoor temperature difference caused by the photo-thermal effect, it significantly improves energy efficiency and environmental adaptability. In view of the frequent occurrence of extreme heat radiation events caused by global climate change, the research and development of related technologies has become an important topic in green material science. To ensure the reliability of the material in actual use, it is necessary to establish a multi-dimensional evaluation system based on parameters such as ultraviolet attenuation rate and infrared reflectivity to conduct comprehensive performance testing.

[0003] Existing sun protection performance testing methods mainly adopt a quasi-static detection paradigm of discrete indicators such as ultraviolet transmittance coefficient, reflectivity parameter, and absorption spectrum characteristics, and fail to effectively characterize the dynamic heterogeneous effects in the multi-layer structure of the composite sun protection and heat insulation material due to the interfacial thermal resistance, thermal expansion difference, and non-linearity of photo-thermal conversion between different internal layer structures, resulting in a systematic deviation between the theoretical test value and the actual working condition performance of the heat insulation performance of the composite sun protection and heat insulation material. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method and system for testing the sun protection performance of a composite sun protection and heat insulation material.

[0005] According to the first aspect of the embodiments of the present invention, a method for testing the sun protection performance of a composite sun protection and heat insulation material is provided, and the technical solution adopted is specifically as follows: Collect the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data; Based on the surface temperature field distribution image, analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface to obtain the interface dynamic effect intensity factor of the material at each acquisition moment; Based on the spectral data of each band and the surface average temperature data, analyze the correlation characteristics of the ultraviolet absorption amount, heat loss amount, and surface temperature rise rate to obtain the photo-thermal conversion efficiency of the material at each acquisition moment; Based on the surface temperature field distribution image and the interface layer temperature data, analyze the thermal stress cumulative coefficient of the material interface, and combine with the photo-thermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment; Analyze the correlation between the interface dynamic effect intensity factor and the cumulative amount of thermal stress history to obtain the dynamic compensation degree of the material in the sunscreen performance test; Based on the dynamic compensation degree, correct the initial sunscreen performance test value to obtain the corrected sunscreen performance value.

[0006] In some embodiments of the present invention, based on the surface temperature field distribution image, analyze the thermal distribution disorder index of the material surface, including: Adopt an image superpixel region segmentation algorithm to divide the surface temperature field distribution image into several superpixel regions; Count the number of the superpixel regions, calculate the area mean value of all the superpixel regions to obtain the thermal distribution disorder index of the material surface.

[0007] In some embodiments of the present invention, based on the surface temperature field distribution image, analyze the coefficient of variation of the thermal distribution disorder of the material surface, including: Based on the surface temperature field distribution image, analyze the uneven degree of the pixel value distribution of all pixel points in the surface temperature field distribution image to obtain the coefficient of variation of the thermal distribution disorder of the material surface.

[0008] In some embodiments of the present invention, analyze the uneven degree of the pixel value distribution of all pixel points in the surface temperature field distribution image, including: Calculate the pixel value standard deviation and the pixel value mean value of all pixel points in the surface temperature field distribution image; Correct the pixel value standard deviation through the pixel value mean value to obtain the uneven degree of the pixel value distribution of all pixel points in the surface temperature field distribution image.

[0009] In some embodiments of the present invention, based on the spectral data of each band and the surface average temperature data, analyze the correlation characteristics of the ultraviolet absorption amount, the heat loss amount and the surface temperature rise rate to obtain the photothermal conversion efficiency of the material at each acquisition moment, including: Based on the spectral data of each band, analyze the total absorbed heat of the material in the ultraviolet band to obtain the ultraviolet absorption amount, and analyze the difference between the reflectivity data of the material in the infrared band at adjacent acquisition moments to obtain the heat loss amount; Based on the surface average temperature data, calculate the surface temperature rise rate of the material at adjacent acquisition moments; According to the ultraviolet absorption amount, the heat loss amount and the surface temperature rise rate, obtain the photothermal conversion efficiency of the material at each acquisition moment.

[0010] In some embodiments of the present invention, based on the surface temperature field distribution image and the interface layer temperature data, the thermal stress accumulation coefficient of the material interface is analyzed, and combined with the photothermal conversion efficiency, the historical cumulative amount of thermal stress at the material interface at each acquisition moment is obtained, including: According to the interface layer temperature data, calculate the average value of the absolute values of the temperature differences between all adjacent two-layer structures in the material to obtain the first coefficient of thermal stress accumulation; Through the Otsu threshold segmentation algorithm, obtain the optimal segmentation threshold of the surface temperature field distribution image, and segment the surface temperature field distribution image into a high-temperature region and a low-temperature region; Respectively count the area of the high-temperature region and the total area of the surface temperature field distribution image to obtain the second coefficient of thermal stress accumulation; Combine the first coefficient of thermal stress accumulation and the second coefficient of thermal stress accumulation to obtain the thermal stress accumulation coefficient of the material interface; According to the thermal stress accumulation coefficient, combined with the photothermal conversion efficiency, obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment.

[0011] In some embodiments of the present invention, according to the thermal stress accumulation coefficient, combined with the photothermal conversion efficiency, the historical cumulative amount of thermal stress at the material interface at each acquisition moment is obtained, including: Collect the ambient temperature and calculate the ambient temperature change rate between adjacent acquisition moments; Correct the photothermal conversion efficiency through the ambient temperature change rate to obtain the corrected photothermal conversion efficiency; According to the thermal stress accumulation coefficient, combined with the corrected photothermal conversion efficiency, traverse all acquisition moments before the current analysis moment to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment.

[0012] In some embodiments of the present invention, analyze the correlation between the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test, including: Based on the interface dynamic effect intensity factor of the material at each acquisition moment, construct a set of interface dynamic effect intensity factors; Based on the historical cumulative amount of thermal stress at the material interface at each acquisition moment, construct a set of historical cumulative amounts of thermal stress; Calculate the Pearson correlation coefficient between the set of interface dynamic effect intensity factors and the set of historical cumulative amounts of thermal stress, and combine the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress of the material at the current analysis moment to obtain the dynamic compensation degree of the material in the sunscreen performance test.

[0013] According to the second aspect of the embodiments of the present invention, a sun protection performance testing system for a composite sun protection and heat insulation material is provided, including: a memory and a processor, wherein: The memory is used to store program codes; The processor is configured to read the program codes stored in the memory and execute the method described in the first aspect of the embodiments of the present invention.

[0014] In some embodiments of the present invention, the processor includes: A data acquisition module, configured to acquire the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data; An interface dynamic effect intensity analysis module, configured to analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface based on the surface temperature field distribution image, and obtain the interface dynamic effect intensity factor of the material at each acquisition moment; A thermal stress history cumulative amount analysis module, configured to analyze the correlation characteristics of the ultraviolet absorption amount, heat loss amount, and surface temperature rise rate based on the spectral data of each band and the surface average temperature data, and obtain the photothermal conversion efficiency of the material at each acquisition moment; and configured to analyze the thermal stress cumulative coefficient of the material interface based on the surface temperature field distribution image and the interface layer temperature data, and combine the photothermal conversion efficiency to obtain the thermal stress history cumulative amount of the material interface at each acquisition moment; A sun protection performance value correction module, configured to analyze the correlation between the interface dynamic effect intensity factor and the thermal stress history cumulative amount, and obtain the dynamic compensation degree of the material in the sun protection performance test; and configured to correct the initial sun protection performance test value through the dynamic compensation degree to obtain the corrected sun protection performance value.

[0015] Compared with the prior art, the sun protection performance testing method and system for a composite sun protection and heat insulation material provided by the present invention have the following beneficial effects: Through the surface temperature field distribution image, the present invention analyzes the thermal distribution disorder index and the coefficient of variation of thermal distribution disorder on the material surface, quantifies the interfacial dynamic effect strength factor of the material, and accurately evaluates the influence of thermal resistance and thermal expansion difference on the thermal conduction stability. At the same time, based on the spectral data of each band and the surface average temperature data, the present invention analyzes the correlation characteristics of the ultraviolet absorption amount, the heat loss amount and the surface temperature rise rate, obtains the photothermal conversion efficiency of the material, and based on the surface temperature field distribution image and the interfacial layer temperature data, analyzes the thermal stress accumulation coefficient of the material interface. Combining with the photothermal conversion efficiency, the historical cumulative amount of thermal stress at the material interface at each acquisition moment is obtained, the cumulative process of thermal stress is traced, and the performance deviation caused by the cross-scale dynamic effect is revealed. Further, the correlation between the interfacial dynamic effect strength factor and the historical cumulative amount of thermal stress is analyzed, the dynamic compensation degree of the material in the sunscreen performance test is obtained, and a real-time compensation value is generated. Through the generated real-time compensation value, the present invention corrects the traditional static test results, thereby overcoming the systematic errors caused by the non-linearity of photothermal conversion, the accumulation of interfacial thermal stress and the anisotropy of multi-layer structures, and improving the reliability of the sunscreen performance test of the sunscreen and heat insulation material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 FIG. is a schematic flowchart of a method for testing the sunscreen performance of a composite sunscreen and heat insulation material provided by an embodiment of the present invention; Figure 2 FIG. is a schematic diagram of the interfacial thermal resistance between a structural layer and a structural layer provided by an embodiment of the present invention; Figure 3 FIG. is a schematic diagram of the basic composition of a system for testing the sunscreen performance of a composite sunscreen and heat insulation material provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features and effects of a method and system for testing the sunscreen performance of a composite sunscreen and heat insulation material proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention pertains. Terms such as "comprising," "including," or any other variant thereof are intended to cover non-exclusive inclusion, such that a circuit structure, article, or device that comprises a series of elements includes not only those elements but also other elements not expressly listed, or elements that are inherent to such article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or device comprising the element.

[0020] The following specifically describes the specific scheme of a method for testing the sun protection performance of a composite sun protection and heat insulation material provided by the present invention in conjunction with the accompanying drawings.

[0021] Please refer to Figure 1 , which shows the basic process of a method for testing the sun protection performance of a composite sun protection and heat insulation material provided by an embodiment of the present invention.

[0022] As Figure 1 shown, a method for testing the sun protection performance of a composite sun protection and heat insulation material provided by an embodiment of the present invention specifically includes: S100: Collect the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data.

[0023] Cut the composite sun protection and heat insulation material into a specified size (such as 10 cm × 10 cm) according to the test standard, ensure that the edges are flat and free of burrs, and use anhydrous ethanol or ultrapure water to remove surface contaminants to avoid interference from stray light or thermal contact.

[0024] Next, install the equipment, such as a spectral detector covering ultraviolet to near-infrared, a thermal imager, a temperature probe, and a micro pressure gauge. Use a standard light source and calibrate the instrument to ensure the accuracy of the equipment.

[0025] According to the experimental requirements (such as constant temperature test, thermal cycling test, or environmental simulation), start the appropriate light source (simulating sunlight), temperature control equipment (two-way temperature control system), and pressure loading equipment.

[0026] Among them, the spectral detector continuously records the spectral data of each band, covering the main bands of the solar spectrum, including the reflectivity and transmittance of the material to ultraviolet, infrared, and visible light; the thermal imager takes real-time pictures of the temperature distribution map on the surface of the material to obtain the surface temperature field distribution image of the material, with a minimum resolvable area of 50 microns; the temperature probe synchronously monitors the temperature of each layer structure inside the material to obtain the interface layer temperature data and simultaneously provides the surface average temperature data of the material; the pressure gauge accurately measures the pressure change generated by the thermal expansion of the material, up to 10 MPa, with a measurement error of less than one-thousandth.

[0027] Noise reduction is performed on all collected spectral, temperature, and pressure data to remove abnormal data. Then, an intelligent algorithm is used to integrate the time and space information of these data to create a complete experimental database. Finally, the sorted data is saved to both the local hard drive and the cloud server through a high-speed transmission channel for convenient subsequent analysis.

[0028] Thus, the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data, are obtained.

[0029] The existing sunscreen test methods do not fully consider the interaction of multiple physical factors and the synergistic effect between different components inside the composite sunscreen and heat insulation material, resulting in a gap between the test results and the actual sunscreen effect. Therefore, in the embodiments of the present invention, by constructing a multi-physical field dynamic coupling model, integrating data at different scales, and correcting the errors in traditional static test methods, the accuracy of sunscreen effect evaluation is improved. The specific steps include S200 to S600.

[0030] S200: Based on the surface temperature field distribution image, analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface to obtain the interface dynamic effect intensity factor of the material at each acquisition moment.

[0031] Based on the surface temperature field distribution image, analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface to obtain the interface dynamic effect intensity factor of the material at each acquisition moment. Among them: In the multi-layer structure of the composite sunscreen and heat insulation material, the interfacial thermal resistance between layers (when two materials are in contact, due to the difference in thermal conductivity, a thermal resistance may form at the interface) is the bottleneck of heat conduction performance. The existence of interfacial thermal resistance between different layers will cause uneven heat transfer between layers, and thus local heat accumulation will occur on the material surface during the sunscreen test, such as Figure 2 shown, so the deviation caused by the interaction force between the current material multi-layer structures to the evaluation of the material's sunscreen performance.

[0032] Based on the above analysis, in the embodiments of the present invention, based on the surface temperature field distribution image, analyze the thermal distribution disorder index of the material surface. The specific implementation method is as follows: First, use the image superpixel region segmentation algorithm to divide the surface temperature field distribution image of the material into several superpixel regions with similar pixel regions. Then, count the number of superpixel regions in the surface temperature field distribution image, calculate the area mean value of all superpixel regions in the surface temperature field distribution image, and calculate the ratio of the number of superpixel regions to the area mean value of the superpixel regions to obtain the thermal distribution disorder index of the material surface as:

[0033] In the formula, represents the thermal distribution disorder index of the material surface at the -th acquisition moment; represents the number of superpixel regions in the surface temperature field distribution image obtained at the -th acquisition moment; represents the average area of all superpixel regions in the surface temperature field distribution image obtained at the -th acquisition moment.

[0034] The larger the value, the more surface temperature fields there are during the sunscreen test of the material, corresponding to the significant heat accumulation phenomenon caused by the interaction of the multi-layer structure of the material; The larger the value, it indicates that there is an obvious heat accumulation phenomenon on the material surface, and the area of the heat accumulation region is small. The complex distribution of the temperature field will intensify the non-linear interaction between the multi-layer material structures, thereby enhancing the influence of the dynamic effect on the heat conduction process and resulting in a greater deviation in the test results.

[0035] It should be noted that since a surface temperature field distribution image of the material is obtained at each acquisition moment, therefore, the thermal distribution disorder index corresponding to each acquisition moment is also obtained here. If there is no special time description in the following, the obtained parameters are all corresponding to each moment.

[0036] Furthermore, considering the overall thermal instability risk of the material, i.e., the surface temperature fluctuation, when the surface temperature changes greatly, the thermal expansion differences in different regions will generate stronger thermal stresses, which makes the heat conduction process of the material more complex. Especially in the case of dynamic temperature changes, the heat transfer and temperature distribution will become unstable, thereby increasing the error of the test results.

[0037] Based on the above analysis, in the embodiments of the present invention, based on the surface temperature field distribution image, the coefficient of variation of the thermal distribution disorder on the material surface is analyzed. Further, based on the surface temperature field distribution image (the larger the pixel value, the higher the temperature), the degree of non-uniformity of the pixel value distribution of all pixel points in the surface temperature field distribution image is analyzed to obtain the coefficient of variation of the thermal distribution disorder on the material surface. The specific implementation method is as follows: First, calculate the standard deviation and the mean value of the pixel values of all pixel points in the surface temperature field distribution image; then, correct the standard deviation of the pixel values through the mean value of the pixel values, that is, calculate the ratio of the standard deviation of the pixel values to the mean value of the pixel values, and the degree of non-uniformity of the pixel value distribution of all pixel points in the surface temperature field distribution image is obtained as:

[0038] In the formula, represents the The non-uniformity of the pixel value distribution of all pixel points in the surface temperature field distribution image acquired at a collection moment; Denote the standard deviation of the pixel values of all pixel points in the surface temperature field distribution image acquired at the th collection moment; Denote the average value of the pixel values of all pixel points in the surface temperature field distribution image acquired at the

[0039] By using the mean value ( ), the standard deviation ( ) is corrected to remove the influence of the overall temperature trend of the temperature field, making the thermal instability analysis more focused on the relative amplitude of temperature fluctuations. The larger the value, the more likely it is that the heat conduction of the material is more affected by local temperature differences and the higher the possibility of instability.

[0040] According to the thermal distribution disorder index and the thermal distribution disorder coefficient of variation of the material surface, the interface dynamic effect intensity factor of the material at each collection moment is obtained as:

[0041] In the formula, Denote the interface dynamic effect intensity factor of the material at the th collection moment; Denote the thermal distribution disorder index of the material surface at the th collection moment; Denote the non-uniformity of the pixel value distribution of all pixel points in the surface temperature field distribution image acquired at the th collection moment.

[0042] The interface dynamic effect intensity factor is used to measure the interference degree of the interface dynamic effect during the sunscreen performance test of the material. The larger the value, the stronger the interface thermal dynamic effect appears during the sunscreen performance test of the material, and the heat conduction becomes more unstable; due to the uneven distribution of heat in the material, local heat accumulation may affect the sunscreen effect of the composite sunscreen and heat insulation material, which will lead to the difference between the actual test result and the theoretical prediction; therefore, during the sunscreen performance test, due to the differences in the interface thermal resistance and thermal expansion coefficient of the material, as well as the non-linear reaction of the photothermal conversion, these dynamic effects become more significant, thus increasing the error of the traditional steady-state thermal conductivity test method.

[0043] S300: Based on the spectral data of each band and the surface average temperature data, analyze the correlation characteristics of the ultraviolet absorption amount, heat loss amount and surface temperature rise rate, and obtain the photothermal conversion efficiency of the material at each collection moment.

[0044] Among the spectral data of each band on the material surface, the ultraviolet absorption determines the total amount of light energy input, the attenuation of the infrared reflectivity characterizes the heat storage capacity (the lower the infrared reflectivity, the greater the heat radiation loss), and the surface temperature rise rate of the material reflects the efficiency of converting light energy into heat energy.

[0045] The sun protection and heat insulation effects of the composite sun protection and heat insulation material mainly depend on the physical and chemical properties of different materials. Through the combination of multi-layer structures, the conduction of heat and the irradiation of ultraviolet rays are reduced. However, the multi-layer structure of the composite sun protection and heat insulation material will produce cross-scale dynamic effects due to the different characteristics between layers, resulting in the accumulation of thermal stress and causing directional differences in thermal conductivity. Specifically, the heat conduction ability of the material is different in different directions, forming specific heat flow channels. Heat conducts faster in some directions and worse in other directions, resulting in more heat loss and ultimately reducing the efficiency of photo-thermal conversion.

[0046] Based on the above analysis, in the embodiments of the present invention, based on the spectral data of each band and the surface average temperature data, the correlation characteristics of the ultraviolet absorption, heat loss, and surface temperature rise rate are analyzed to obtain the photo-thermal conversion efficiency of the material at each acquisition moment. The specific implementation method is as follows: First, based on the ultraviolet band data in the spectral data of each band, where the ultraviolet band range is 200 - 400 nm, the total absorbed heat of the material in the ultraviolet band is analyzed, and the ultraviolet absorption is obtained as:

[0047] In the formula, represents the absorption of ultraviolet rays by the material at the th acquisition moment; represents the reflectivity of the material to ultraviolet rays at the th acquisition moment; represents the transmittance of the material to ultraviolet rays at the th acquisition moment; represents the integration within the ultraviolet band range.

[0048] A higher ultraviolet absorption ( ) indicates that the material can effectively absorb ultraviolet rays and reduce the radiation energy transmitted to the lower layer.

[0049] At the same time, based on the infrared band data in the spectral data of each band, where the infrared band range is 700 - 1400 nm, the difference in the reflectivity data of the material in the infrared band between adjacent acquisition moments is analyzed, and the heat loss is obtained as:

[0050] In the formula, represents the The infrared band reflection attenuation of the material at a collection moment, i.e., the heat loss amount; Indicates the reflectivity of the material to the infrared band at the Indicates the reflectivity of the material to the infrared band at the

[0051] The infrared band reflection attenuation of the material, as a measure of heat loss, the larger the value, the greater the heat loss of the material, resulting in a reduction in the effective thermal energy output.

[0052] And, based on the surface average temperature data, the surface temperature rise rate of the material at adjacent collection moments is calculated as:

[0053] In the formula, Indicates the surface temperature rise rate of the material at the Indicates the difference in the surface average temperature data of the material at the and the Indicates the difference between the and the

[0054] The larger the value, the more heat energy the material accumulates in a shorter time, indicating that the material has a stronger ability to convert light energy.

[0055] Finally, according to the ultraviolet absorption amount, heat loss amount and surface temperature rise rate, the photothermal conversion efficiency of the material at each collection moment is obtained as:

[0056] In the formula, Indicates the photothermal conversion efficiency of the material at the Indicates the surface temperature rise rate of the material at the Indicates the infrared band reflection attenuation of the material at the Indicates the ultraviolet absorption amount of the material at the

[0057] Is directly related to the photothermal conversion effect of the material, indicating the change in heat after the material absorbs light energy; when calculating the photothermal conversion efficiency, it is actually judging whether the light energy absorbed by the material can be effectively converted into heat energy, taking into account the heat energy lost due to reflection; the photothermal conversion efficiency It mainly reflects the ability of the material to convert light energy into heat energy. The smaller the value, the lower the photothermal conversion efficiency of the composite sunscreen and heat insulation material, indicating that the thermal stress in the multi-layer structure of the composite sunscreen and heat insulation material gradually accumulates, resulting in inconsistent thermal conductivity between different layers. This phenomenon may accelerate the accumulation rate of thermal stress at the material interface during subsequent tests.

[0058] S400: Based on the surface temperature field distribution image and the interface layer temperature data, analyze the thermal stress accumulation coefficient at the material interface, and combine with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment.

[0059] The composite sunscreen and heat insulation material usually consists of multiple layers of different materials, and the thermal conductivity and thermal expansion coefficient of each layer are different. When the material absorbs heat under sunlight, the temperature rises, and the expansion degrees of different materials are also different. These expansion differences lead to the gradual accumulation of thermal stress inside the material, forming an uneven stress distribution. Over time, this uneven stress causes heat to stay inside the material, affecting its heat insulation performance and thus reducing the sunscreen effect.

[0060] Based on the above analysis, in some embodiments of the present invention, based on the surface temperature field distribution image and the interface layer temperature data, analyze the thermal stress accumulation coefficient at the material interface, and combine with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment. The specific implementation method is as follows: First, according to the interface layer temperature data, for each acquisition moment, calculate the average value of the absolute values of the temperature differences between all adjacent two-layer structures inside the material to obtain the first thermal stress accumulation coefficient generated by the expansion and extrusion of the multi-layer structure of the material at each acquisition moment.

[0061] At the same time, the phenomenon of thermal stress accumulation caused by the expansion and extrusion between the multi-layer structures inside the material will cause the temperature of local areas on the material surface to rise abnormally. Therefore, for the surface temperature field distribution image obtained at each acquisition moment, through the Otsu threshold segmentation algorithm, obtain the optimal segmentation threshold of the surface temperature field distribution image, and segment the surface temperature field distribution image into a high-temperature area (foreground) and a low-temperature area (background); respectively count the area of the high-temperature area (which can be obtained by counting the number of foreground pixel points) and the total area of the surface temperature field distribution image (which can be obtained by counting the number of all foreground and background pixel points), and calculate the ratio of the area of the high-temperature area to the total area of the surface temperature field distribution image to obtain the second thermal stress accumulation coefficient generated by the expansion and extrusion of the multi-layer structure of the material at each acquisition moment.

[0062] Then, combine the first thermal stress accumulation coefficient and the second thermal stress accumulation coefficient to obtain the thermal stress accumulation coefficient at the material interface as:

[0063] In the formula, represents the cumulative coefficient of thermal stress at the material interface at the -th acquisition moment; represents the first cumulative coefficient of thermal stress generated by the expansion and extrusion of the material due to the multi-layer structure at the -th acquisition moment; represents the second cumulative coefficient of thermal stress generated by the expansion and extrusion of the material due to the multi-layer structure at the -th acquisition moment.

[0064] The larger the value, the greater the temperature difference between adjacent two-layer structures, indicating that the thermal stress generated between the structural interfaces inside the material is more significant when the temperature rises; The larger the value, the larger the area of the high-temperature region relative to the total area of the surface temperature field distribution image, indicating that the thermal stress generated between the structural interfaces inside the material is more significant when the temperature rises; The larger the value, it indicates that a large amount of thermal stress accumulated inside the material at the current moment has a greater actual impact on the sun protection effect.

[0065] Due to the gradual accumulation of thermal stress inside the material, the stress distribution becomes uneven, which will affect the heat insulation effect of the material and thus reduce the sun protection performance. And this uneven stress will continue to intensify over time. Therefore, when analyzing the sun protection effect at a certain moment, it is necessary to consider the historical accumulation of thermal stress on the material interface.

[0066] Therefore, finally, according to the cumulative coefficient of thermal stress, combined with the photothermal conversion efficiency, the historical cumulative amount of thermal stress at the material interface at each acquisition moment is obtained. More specifically, the ambient temperature is collected, and the ambient temperature change rate between adjacent acquisition moments (the ratio of the difference in ambient temperature between adjacent acquisition moments to the time difference between adjacent acquisition moments) is calculated; the photothermal conversion efficiency is corrected by the ambient temperature change rate to obtain the corrected photothermal conversion efficiency; according to the cumulative coefficient of thermal stress, combined with the corrected photothermal conversion efficiency, all acquisition moments before the current analysis moment are traversed to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment. The formula for constructing the historical cumulative amount of thermal stress at the material interface at the -th acquisition moment is:

[0067] In the formula, represents the historical cumulative amount of thermal stress at the material interface at the -th acquisition moment; represents the number of all acquisition moments from the start of the test to the -th acquisition moment; represents the collection moments; represents the photothermal conversion efficiency of the material at the represents the rate of change of the ambient temperature between the and represents the cumulative coefficient of thermal stress at the material interface at the

[0068] The value reflects the total thermal stress accumulated at the material interface from the start of the test to the current collection moment due to temperature changes and photothermal conversion.

[0069] S500: Analyze the correlation between the interface dynamic effect strength factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test.

[0070] Analyze the correlation between the interface dynamic effect strength factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test. The specific implementation method is as follows: First, based on the interface dynamic effect strength factor of the material at each collection moment, construct a set of interface dynamic effect strength factors. More specifically, construct a set of interface dynamic effect strength factors by using the interface dynamic effect strength factor of the material within the historical 5 minutes (the 5 minutes before the current analysis moment) during the sunscreen performance test of the composite sunscreen and heat insulation material.

[0071] At the same time, based on the historical cumulative amount of thermal stress at the material interface at each collection moment, construct a set of historical cumulative amounts of thermal stress. More specifically, construct a set of historical cumulative amounts of thermal stress by using the historical cumulative amount of thermal stress of the material within the historical 5 minutes (the 5 minutes before the current analysis moment) during the sunscreen performance test of the composite sunscreen and heat insulation material.

[0072] Then, calculate the Pearson correlation coefficient between the set of interface dynamic effect strength factors and the set of historical cumulative amounts of thermal stress, and combine the interface dynamic effect strength factor and the historical cumulative amount of thermal stress of the material at the current analysis moment to obtain the dynamic compensation degree of the material in the sunscreen performance test. The calculation formula for the dynamic compensation degree of the material at the collection moment in the sunscreen performance test is:

[0073] In the formula, represents the dynamic compensation degree of the material at the collection moment in the sunscreen performance test; represents the interface dynamic effect strength factor of the material at the collection moment; The historical cumulative amount of thermal stress at the material interface at a collection moment; Denote the Set of interface dynamic effect strength factors corresponding to the Denote the Set of historical cumulative amounts of thermal stress corresponding to the Denote the Pearson correlation coefficient between the set of interface dynamic effect strength factors and the set of historical cumulative amounts of thermal stress corresponding to the

[0074] The closer the value is to 1, it indicates that there is a significant positive correlation between the disordered distribution of the temperature field on the material surface and the historical non - linear accumulation of thermal stress at the material interface, meaning that there is a strong positive correlation between the disorder of the temperature field on the material surface and the historical change of thermal stress. The disorder of the temperature field will aggravate the thermal stress at the material interface, thus having a greater impact on the sun - protection effect; Represents the real - time dynamic compensation degree, quantifying the degree of dynamic correction required for the material during the test process, The higher the value, the greater the difference between the measured sun - protection effect value of the material and the actual value, and this difference is more significantly affected by the environment and dynamic load. Through appropriate dynamic compensation measures, this deviation can be effectively reduced, improving the test accuracy and the evaluation accuracy of the sun - protection effect of the material.

[0075] S600: Correct the initial sun - protection performance test value through the dynamic compensation degree to obtain the corrected sun - protection performance value.

[0076] Correct the initial sun - protection performance test value through the dynamic compensation degree to obtain the corrected sun - protection performance value. The specific implementation method is as follows: First, calculate the initial sun - protection performance test value of the composite sun - protection and heat - insulation material through the standard sun - protection performance evaluation method (such as ultraviolet transmittance, thermal conductivity, etc.). Then, correct the initial sun - protection performance test value through the dynamic compensation degree to obtain the corrected sun - protection performance value as:

[0077] In the formula, Denote the Corrected sun - protection performance value corresponding to the Denote the Initial sun - protection performance value corresponding to the Denote the Dynamic compensation degree of the material during the sun - protection performance test at the

[0078] Corrected sun - protection performance value It can effectively reflect the change of the sunscreen effect caused by environmental changes, temperature fluctuations and non-linear factors during the actual use of the material, thereby improving the accuracy and reliability of the sunscreen performance evaluation.

[0079] Please refer to Figure 3 , which shows the basic composition of a sunscreen performance test system for a composite sunscreen and heat insulation material provided by an embodiment of the present invention.

[0080] As Figure 3 shown, a sunscreen performance test system for a composite sunscreen and heat insulation material includes: a memory 10 and a processor 20, wherein: The memory 10 is used to store program codes; The processor 20 is configured to read the program codes stored in the memory 10 and execute the operations of collecting the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data; based on the surface temperature field distribution image, analyzing the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface to obtain the interface dynamic effect intensity factor of the material at each acquisition moment; based on the spectral data of each band and the surface average temperature data, analyzing the correlation characteristics of the ultraviolet absorption amount, heat loss amount and surface temperature rise rate to obtain the photo-thermal conversion efficiency of the material at each acquisition moment; based on the surface temperature field distribution image and the interface layer temperature data, analyzing the thermal stress accumulation coefficient at the material interface, and combining with the photo-thermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment; analyzing the correlation between the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test; and correcting the initial sunscreen performance test value through the dynamic compensation degree to obtain the corrected sunscreen performance value.

[0081] Further, the processor 20 includes a data acquisition module 21, an interface dynamic effect intensity analysis module 22, a thermal stress historical cumulative amount analysis module 23 and a sunscreen performance value correction module 24. Wherein: The data acquisition module 21 is used to collect the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data; The interface dynamic effect intensity analysis module 22 is used to analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface based on the surface temperature field distribution image to obtain the interface dynamic effect intensity factor of the material at each acquisition moment; The thermal stress history cumulative amount analysis module 23 is configured to analyze the correlation characteristics of the ultraviolet absorption amount, the heat loss amount, and the surface temperature rise rate based on the spectral data of each band and the surface average temperature data, so as to obtain the photothermal conversion efficiency of the material at each acquisition moment; and is configured to analyze the thermal stress cumulative coefficient of the material interface based on the surface temperature field distribution image and the interface layer temperature data, and combine the photothermal conversion efficiency to obtain the thermal stress history cumulative amount of the material interface at each acquisition moment; The sun protection performance value correction module 24 is configured to analyze the correlation between the interface dynamic effect intensity factor and the thermal stress history cumulative amount, so as to obtain the dynamic compensation degree of the material in the sun protection performance test; and is configured to correct the initial sun protection performance test value through the dynamic compensation degree to obtain the corrected sun protection performance value.

[0082] It should be noted that the above sequence of embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0083] Each embodiment in this specification is described in a progressive manner, and the same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for testing the sun protection performance of a composite sun protection and heat insulation material, characterized in that, The method includes: Collecting the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the interface layer temperature data; Based on the surface temperature field distribution image, analyzing the thermal distribution disorder index and thermal distribution disorder coefficient of variation of the material surface to obtain the interface dynamic effect intensity factor of the material at each acquisition moment; Based on the spectral data of each band and the surface average temperature data, analyzing the correlation characteristics of the ultraviolet absorption amount, heat loss amount, and surface temperature rise rate to obtain the photothermal conversion efficiency of the material at each acquisition moment; Based on the surface temperature field distribution image and the interface layer temperature data, analyzing the thermal stress accumulation coefficient of the material interface, and combining with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment; Analyzing the correlation between the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test; Correcting the initial sunscreen performance test value through the dynamic compensation degree to obtain the corrected sunscreen performance value.

2. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 1, characterized in that, Based on the surface temperature field distribution image, analyzing the thermal distribution disorder index of the material surface, including: Using an image superpixel region segmentation algorithm to divide the surface temperature field distribution image into several superpixel regions; Counting the number of the superpixel regions, calculating the area average value of all the superpixel regions to obtain the thermal distribution disorder index of the material surface.

3. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 1 or 2, characterized in that Based on the surface temperature field distribution image, analyzing the thermal distribution disorder coefficient of variation of the material surface, including: Based on the surface temperature field distribution image, analyzing the unevenness of the pixel value distribution of all pixel points in the surface temperature field distribution image to obtain the thermal distribution disorder coefficient of variation of the material surface.

4. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 3, characterized in that, Analyzing the unevenness of the pixel value distribution of all pixel points in the surface temperature field distribution image, including: Calculating the pixel value standard deviation and pixel value average value of all pixel points in the surface temperature field distribution image; Correcting the pixel value standard deviation through the pixel value average value to obtain the unevenness of the pixel value distribution of all pixel points in the surface temperature field distribution image.

5. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 1, characterized in that, Based on the spectral data of each band and the surface average temperature data, analyzing the correlation characteristics of the ultraviolet absorption amount, heat loss amount, and surface temperature rise rate to obtain the photothermal conversion efficiency of the material at each acquisition moment, including: Based on the spectral data of each band, analyzing the total absorbed heat of the material in the ultraviolet band to obtain the ultraviolet absorption amount, and analyzing the difference in the reflectivity data of the material in the infrared band between adjacent acquisition moments to obtain the heat loss amount; Based on the surface average temperature data, calculating the surface temperature rise rate of the material between adjacent acquisition moments; According to the ultraviolet absorption amount, the heat loss amount, and the surface temperature rise rate, obtaining the photothermal conversion efficiency of the material at each acquisition moment.

6. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 1, characterized in that, Based on the surface temperature field distribution image and the interface layer temperature data, analyzing the thermal stress accumulation coefficient of the material interface, and combining with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment, including: Calculate the mean value of the absolute value of the temperature difference between all adjacent two-layer structures in the material according to the temperature data of the interface layer to obtain the first coefficient of thermal stress accumulation; Obtain the optimal segmentation threshold of the surface temperature field distribution image through the Otsu threshold segmentation algorithm, and segment the surface temperature field distribution image into a high-temperature region and a low-temperature region; Respectively count the area of the high-temperature region and the total area of the surface temperature field distribution image to obtain the second coefficient of thermal stress accumulation; Combine the first coefficient of thermal stress accumulation and the second coefficient of thermal stress accumulation to obtain the thermal stress accumulation coefficient of the material interface; According to the thermal stress accumulation coefficient, combine with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment.

7. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 6, characterized in that, According to the thermal stress accumulation coefficient, combine with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment, including: Collect the ambient temperature and calculate the ambient temperature change rate between adjacent acquisition moments; Correct the photothermal conversion efficiency through the ambient temperature change rate to obtain the corrected photothermal conversion efficiency; According to the thermal stress accumulation coefficient, combine with the corrected photothermal conversion efficiency, and traverse all acquisition moments before the current analysis moment to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment.

8. The method for testing the sun protection performance of the composite sun protection and heat insulation material according to claim 1, characterized in that, Analyze the correlation between the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress to obtain the dynamic compensation degree of the material in the sunscreen performance test, including: Based on the interface dynamic effect intensity factor of the material at each acquisition moment, construct a set of interface dynamic effect intensity factors; Based on the historical cumulative amount of thermal stress at the material interface at each acquisition moment, construct a set of historical cumulative amounts of thermal stress; Calculate the Pearson correlation coefficient between the set of interface dynamic effect intensity factors and the set of historical cumulative amounts of thermal stress, and combine the interface dynamic effect intensity factor and the historical cumulative amount of thermal stress of the material at the current analysis moment to obtain the dynamic compensation degree of the material in the sunscreen performance test.

9. A sun protection performance testing system for a composite sun protection and heat insulation material, characterized in that, The system includes: a memory and a processor, wherein: The memory is used to store program codes; The processor is used to read the program codes stored in the memory and execute the method according to any one of claims 1 to 8.

10. The sunscreen performance testing system for the composite sunscreen and heat insulation material according to claim 9, characterized in that, The processor includes: A data acquisition module, which is used to acquire the surface temperature field distribution image and surface average temperature data of the material, as well as the spectral data of each band and the temperature data of the interface layer; An interface dynamic effect intensity analysis module, which is used to analyze the thermal distribution disorder index and thermal distribution disorder coefficient of variation on the material surface based on the surface temperature field distribution image to obtain the interface dynamic effect intensity factor of the material at each acquisition moment; A historical cumulative amount of thermal stress analysis module, which is used to analyze the correlation characteristics of the ultraviolet absorption amount, heat loss amount and surface temperature rise rate based on the spectral data of each band and the surface average temperature data to obtain the photothermal conversion efficiency of the material at each acquisition moment; and is used to analyze the thermal stress accumulation coefficient of the material interface based on the surface temperature field distribution image and the interface layer temperature data, and combine with the photothermal conversion efficiency to obtain the historical cumulative amount of thermal stress at the material interface at each acquisition moment; A sunscreen performance value correction module, which is used to analyze the correlation between the interface dynamic effect intensity factor and the cumulative amount of thermal stress history, so as to obtain the dynamic compensation degree of the material in the sunscreen performance test; and is used to correct the initial sunscreen performance test value through the dynamic compensation degree to obtain the corrected sunscreen performance value.

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