Method and device for obtaining interfacial shear strength of composite material based on macro-micro statistics

Abstract

This application relates to the field of composite material mechanical property testing technology, and particularly to a method and device for obtaining the interfacial shear strength of composite materials based on macro- and micro-statistics. The method provided in this application includes: obtaining the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; setting a preset assumption about the length relationship between the average fiber length and the critical fiber length, and determining the corresponding interfacial shear strength acquisition method based on the preset assumption, wherein the interfacial shear strength acquisition method is determined based on the mixing law and the shear hysteresis model; obtaining a provisional interfacial shear strength based on the interfacial shear strength acquisition method and the macroscopic mechanical parameters and microstructural statistical parameters; obtaining the critical fiber length based on the shear hysteresis model and the provisional interfacial shear strength, verifying the preset assumption, and determining the final interfacial shear strength. The method provided in this application can accurately reflect the true interfacial shear strength of the composite material.

Description

Technical Field

[0001] This application relates to the field of mechanical property testing technology for composite materials, and in particular to a method and device for obtaining the interfacial shear strength of composite materials based on macro-micro statistics. Background Technology

[0002] The macroscopic mechanical properties of fiber-reinforced composites are highly dependent on the interfacial bonding quality between the fibers and the matrix, among which interfacial shear strength (IFSS) is the core indicator for evaluating interfacial performance. Accurately obtaining this parameter is of great significance for material formulation optimization and failure analysis.

[0003] Currently, traditional methods for analyzing interfacial shear strength generally employ microscopic mechanical techniques such as single-fiber pull-out or micro-debonding methods. These methods rely on micromanipulation to prepare and load individual fibers, resulting in cumbersome operations, low testing efficiency, and large data dispersion. Furthermore, these methods typically use microscopic samples prepared under ideal laboratory conditions, which fails to reflect the true impact of strong shear flow fields, pressure holding, and non-isothermal cooling on the interface in actual industrial molding processes, leading to results that do not accurately reflect the material's true interfacial shear strength.

[0004] In summary, there is an urgent need for a new interfacial shear strength testing and calculation technology to solve the technical problems existing in the traditional solutions. Summary of the Invention

[0005] This application provides a method and device for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, and provides a method for obtaining the interfacial shear strength of composite materials that can accurately reflect the true interfacial shear strength of the material.

[0006] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, the method comprising: Obtain the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructural statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructural statistical parameters include at least the average fiber length; A preset assumption is set regarding the length relationship between the average fiber length and the critical fiber length, and a corresponding method for obtaining the interfacial shear strength is determined based on the preset assumption. The method for obtaining the interfacial shear strength is determined based on the hybrid law and the shear hysteresis model. Based on the method for obtaining the interfacial shear strength, and in combination with the macroscopic mechanical parameters and the microscopic structural statistical parameters, a provisional interfacial shear strength is obtained. Based on the shear hysteresis model, the critical fiber length is obtained by combining the provisional interfacial shear strength, and the preset assumption is verified to determine the final interfacial shear strength.

[0007] The method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics proposed in this application abandons the traditional approach of single-fiber microscopic sample preparation and testing. By directly acquiring the macroscopic mechanical parameters and microstructural statistical parameters of the composite material under test, setting preset assumptions, and selecting an interfacial shear strength acquisition method based on the mixing law and shear hysteresis model, macroscopic properties and microscopic statistical characteristics are integrated for obtaining the interfacial shear strength. This method does not rely on the micromanipulation and testing process of single fibers, reducing the operational difficulty and improving testing efficiency. At the same time, since the microstructural statistical parameters used can reflect the spatial distribution characteristics of the fiber group in the composite material, it avoids the errors caused by local defects of single fibers or randomness in sample preparation in traditional methods, thus improving the statistical stability and accuracy of the obtained interfacial shear strength. In addition, this application uses an iterative mechanism of "preset assumption - provisional strength - critical length verification" to ensure that the finally determined interfacial shear strength is logically consistent with the acquisition method used, further guaranteeing the reliability of the results.

[0008] Secondly, embodiments of this application provide a device for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, the device comprising: The parameter acquisition unit is used to acquire the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructural statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructural statistical parameters include at least the average fiber length. The assumption setting unit is used to set a preset assumption about the length relationship between the average fiber length and the critical fiber length, and to determine the corresponding interface shear strength acquisition method based on the preset assumption. The interface shear strength acquisition method is determined based on the hybrid law and the shear hysteresis model. The data calculation unit is used to obtain the provisional interface shear strength based on the interface shear strength acquisition method, combined with the macroscopic mechanical parameters and the microscopic structural statistical parameters. The assumption verification unit is used to obtain the critical fiber length based on the provisional interfacial shear strength and verify the preset assumption to determine the final interfacial shear strength.

[0009] Thirdly, embodiments of this application provide a computer device, including: The system includes a memory and a processor, which are interconnected and communicate with each other. The memory stores computer instructions, and the processor executes these computer instructions to perform the composite material interface shear strength acquisition method based on macro-micro statistics as described in the first aspect. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 A step diagram illustrating a method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, provided for embodiments of this application; Figure 2 A flowchart illustrating a specific implementation of a method for testing and calculating interfacial shear strength in composite materials, provided in this application embodiment; Figure 3 A schematic diagram of the tensile mechanical properties curve of a composite material and the tensile mechanical properties curve of a matrix provided for embodiments of this application; Figure 4 This is a schematic diagram of the spatial distribution and morphology of fibers in a composite material, provided as an embodiment of this application. Figure 5 A schematic diagram of the probability density distribution of fiber spatial angles obtained based on microscopic statistics, provided for an embodiment of this application; Figure 6 A schematic diagram of the fiber length probability density distribution obtained based on microstatistics, provided for an embodiment of this application; Figure 7 A schematic diagram of a composite material interface shear strength acquisition device based on macro-micro statistics provided in this application embodiment; Figure 8 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] This application provides a method for obtaining the interfacial shear strength of composite materials based on macro- and micro-statistics. It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0014] The first embodiment of this application provides a method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, such as... Figure 1 As shown, it includes the following steps: Step 110: Obtain the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructural statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructural statistical parameters include at least the average fiber length.

[0015] In this embodiment, it is first necessary to obtain the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested.

[0016] Macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material under test. They can reflect the mechanical response of the material at the macroscopic level, such as tensile strength and tensile modulus.

[0017] Microstructural statistical parameters are used to characterize the spatial distribution of fibers in a composite material under test. Specifically, feasible microscopic detection techniques, such as microscopic imaging, can be used to probe the internal structure of the composite material and obtain microscopic data that reflects its internal structural characteristics. Further statistical analysis of this microscopic data yields the microstructural statistical parameters. These parameters include at least the average fiber length obtained through statistical analysis; this parameter is a key indicator characterizing the length characteristics of the fibers in the spatial distribution of the composite material.

[0018] It should be noted that, since this embodiment requires the simultaneous acquisition of both the macroscopic mechanical properties and microscopic structural statistical parameters of the material, and the traditional single-fiber microscopic sample preparation and testing process can only perform localized testing on a single fiber, it is impossible to obtain macroscopic mechanical parameters or statistically acquire microscopic structural statistical parameters on the same sample. Therefore, this embodiment is not applicable to traditional microscopic sample preparation processes. As an alternative, this embodiment proposes using a standard molding process to prepare the composite material under test for testing and data acquisition, thereby providing a reliable data foundation for subsequently fusing macroscopic and microscopic information to obtain interfacial shear strength.

[0019] Step 120: Set a preset assumption about the relationship between the average fiber length and the critical fiber length, and determine the corresponding method for obtaining the interfacial shear strength based on the preset assumption. The method for obtaining the interfacial shear strength is determined based on the mixed law and the shear hysteresis model.

[0020] This embodiment proposes to determine the specific method for obtaining the interface shear strength by using the hybrid law and the shear hysteresis model.

[0021] The rule of mixture is a model used to predict the elastic modulus, strength, and other properties of fiber-reinforced composites. Its basic idea is to estimate the macroscopic properties of the composite material by weighted averaging the volume fractions of the fiber and matrix components. The standard model of the rule of mixture is as follows: in, This represents the macroscopic mechanical parameters of the composite material being tested, such as tensile strength. This represents the macroscopic mechanical parameters of the matrix in the composite material being tested, such as tensile strength or yield strength. The volume fraction of fibers in the composite material being tested is expressed as [fiber volume fraction], and the volume fraction of the matrix in the composite material being tested is expressed as [matrix volume fraction]. express.

[0022] The shear hysteresis model is a theoretical model in materials science that describes how axial stress in composite materials is transferred from the matrix to the fibers through interfacial shear. This model characterizes the influence of fiber geometry and interfacial properties on the strength of the composite material using microscopic parameters such as interfacial shear strength, average fiber length, and critical fiber length.

[0023] This embodiment integrates the two models mentioned above. The specific integration method can be: multiplying or dividing the fiber-related terms in the hybrid law by the correction coefficient derived from the shear hysteresis model, or directly adding the compensation term derived from the shear hysteresis model to the hybrid law. This embodiment does not impose any specific limitations.

[0024] Through this fusion, this embodiment combines the microscopic characteristics of the shear hysteresis model response with the macroscopic characteristics reflected by the mixing law, introduces the interfacial shear strength into the mixing law, and establishes the relationship between the macroscopic mechanical parameters and microscopic interfacial parameters of the composite material under test.

[0025] In shear hysteresis models, different length relationships between the average fiber length and the critical fiber length lead to different representations of the fiber's contribution to material strength. Therefore, this embodiment proposes: first, setting a preset assumption about the length relationship between the two, and then determining the corresponding method for obtaining the interfacial shear strength based on this assumption.

[0026] The presuppositions include two mutually exclusive scenarios: Assumption 1, the average fiber length is less than the critical fiber length; Assumption 2, the average fiber length is greater than or equal to the critical fiber length. Based on these different assumptions, the expression for the interfacial shear strength will change accordingly.

[0027] Step 130: Based on the method for obtaining the interfacial shear strength, and in combination with macroscopic mechanical parameters and microscopic structural statistical parameters, obtain the provisional interfacial shear strength.

[0028] After determining the method for obtaining the interfacial shear strength corresponding to the preset assumption, the provisional interfacial shear strength is calculated using this method based on the macroscopic mechanical parameters and microstructural statistical parameters obtained in the preceding steps.

[0029] The validity of this provisional interface shear strength depends on whether its corresponding initial presupposition holds, and therefore requires further verification.

[0030] Step 140: Based on the shear hysteresis model and the provisional interfacial shear strength, obtain the critical fiber length and verify the preset assumptions to determine the final interfacial shear strength.

[0031] The core of this step is to verify the presuppositions made in the preceding steps.

[0032] Specifically, based on the parameters obtained in the aforementioned steps, such as the provisional interface shear strength, macroscopic mechanical parameters, and microstructural statistical parameters, the critical fiber length corresponding to this provisional interface shear strength is inverted from the shear hysteresis model. Subsequently, the inverted critical fiber length is compared with the average fiber length statistically obtained from the microstructural statistical parameters.

[0033] If the relationship between the two values ​​is consistent with the initial preset assumption set in the aforementioned steps, then the assumption is proven to be valid. Conversely, if the relationship between the two values ​​contradicts the initial preset assumption, then the assumption is proven to be invalid. In this case, another preset assumption is selected, and the process of obtaining the interface shear strength is repeated until the final interface shear strength that satisfies the preset assumption is obtained.

[0034] The second embodiment of this application further specifies the method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics in the first embodiment in a more detailed and specific way. Some or all of the technical features in the second embodiment can be combined with or replaced by the first embodiment, either individually or in combination, to obtain more feasible methods for obtaining the interfacial shear strength of composite materials based on macro-micro statistics.

[0035] The method for obtaining the interfacial shear strength of composite materials based on macro- and micro-statistics in the second embodiment of this application will be described in detail below: Optionally, based on the shear hysteresis model, the critical fiber length is obtained by combining a provisional interfacial shear strength and the preset assumptions are verified to determine the final interfacial shear strength. This includes: comparing the average fiber length with the critical fiber length; if the length relationship between the average fiber length and the critical fiber length does not conform to the preset assumptions, a new preset assumption and the corresponding interfacial shear strength acquisition method are selected, and the provisional interfacial shear strength is obtained again; based on the shear hysteresis model, a new critical fiber length is obtained by combining the newly obtained provisional interfacial shear strength and the newly selected preset assumptions are verified to determine the final interfacial shear strength; if the length relationship between the average fiber length and the critical fiber length conforms to the preset assumptions, the provisional interfacial shear strength is determined as the final interfacial shear strength.

[0036] This embodiment defines the verification process of the preset assumptions and the process of determining the final interface shear strength.

[0037] Specifically, the first step is to perform a comparison operation, which involves comparing the average fiber length obtained statistically from the microstructure statistical parameters with the critical fiber length obtained by inversion based on the provisional interface shear strength and shear hysteresis model, in order to determine the actual length relationship between the two.

[0038] Specifically, the verification and determination process can be divided into the following two cases: First scenario: The assumption is invalid (the relationship does not hold).

[0039] If the comparison results show that the actual length relationship between the statistically obtained average fiber length and the calculated critical fiber length does not match the previously set initial preset assumption, then the initial preset assumption is deemed invalid. In this case, the current calculation results need to be discarded, and the process should return to step 120 to select another preset assumption. Subsequently, based on the newly selected preset assumption, the corresponding method for obtaining the interfacial shear strength is determined, and the relevant calculations are performed again to obtain a new provisional interfacial shear strength. Step 140 is then executed again, that is, based on the shear hysteresis model and this newly obtained provisional interfacial shear strength, a new critical fiber length is derived, and the newly selected preset assumption is verified.

[0040] The second scenario: The assumption is true (the relationship is met).

[0041] If the comparison results show that the actual length relationship between the average fiber length and the calculated critical fiber length is consistent with the previously set initial preset assumption, then the initial preset assumption is deemed valid. In this case, there is no need to recalculate, and the provisional interfacial shear strength can be directly determined as the final interfacial shear strength.

[0042] Through the above iterative verification mechanism, it can be ensured that the mathematical model used in the calculation process matches the actual physical state of the composite material under test, i.e. the fiber length state, thus guaranteeing the accuracy of the final obtained interfacial shear strength.

[0043] Optionally, the macroscopic mechanical parameters include at least the tensile strength of the composite material under test, the tensile strength of the fibers in the composite material under test, and the tensile strength or yield strength of the matrix in the composite material under test; the microstructure statistical parameters include at least the statistical distribution data of fiber length, the statistical distribution data of fiber spatial angle, the statistical distribution data of fiber diameter, the average fiber length, the fiber orientation utilization coefficient, the average fiber diameter, and the fiber volume fraction; obtaining the microstructure statistical parameters of the composite material under test includes: obtaining an image of the spatial distribution of fibers in the composite material under test; performing statistics based on the image to obtain the statistical distribution data of fiber length, the statistical distribution data of fiber spatial angle, and the statistical distribution data of fiber diameter, wherein the statistical distribution data of fiber spatial angle characterizes the spatial angle between the fiber and the tensile direction of the composite material under test; obtaining the average fiber length based on the statistical distribution data of fiber length, obtaining the fiber orientation utilization coefficient based on the statistical distribution data of fiber spatial angle, and obtaining the average fiber diameter based on the statistical distribution data of fiber diameter; and obtaining the fiber volume fraction according to a preset fiber volume acquisition method.

[0044] In this embodiment, the specific composition and acquisition methods of the aforementioned macroscopic mechanical parameters and microscopic structural statistical parameters are further defined to provide complete and accurate basic data for subsequent interfacial shear strength.

[0045] Specifically, the tensile strength of the composite material under test, a macroscopic mechanical parameter, is obtained by performing macroscopic mechanical tensile tests on the composite material under test and recording the stress-strain data during the test process.

[0046] The tensile strength of the fibers and the tensile strength or yield strength of the matrix in the composite material under test, which are macroscopic mechanical parameters, can also be obtained through the aforementioned mechanical tensile tests to obtain data that conforms to the actual composite material under test. Alternatively, if the fibers and matrix are existing standard materials, the nominal values ​​of the standard materials can be used directly.

[0047] In practical applications, different types of matrices can be selected depending on the intended use of the composite material being tested. For different types of matrices, either the tensile strength or the yield strength of the matrix can be selected as the macroscopic mechanical parameter, depending on the specific circumstances.

[0048] To characterize the complex fiber distribution within the composite material, this embodiment introduces multi-dimensional statistical parameters of the microstructure. The acquisition of these parameters primarily relies on a combination of microscopic imaging techniques and image processing analysis techniques.

[0049] The internal structure of the composite material sample under test is observed using a microscopic imaging device, generating images reflecting the spatial distribution of fibers. These images are then digitally processed and statistically analyzed to extract statistical distribution data for fiber length, fiber spatial angles, and fiber diameter. The fiber spatial angle specifically refers to the angle between the fiber axis and the tensile direction (i.e., the load direction) of the composite material under test; this angle characterizes the efficiency of the fiber in bearing the load.

[0050] Microscopic imaging technology can be Micro-CT technology or other technologies that can achieve the same requirements.

[0051] Based on the above statistical distribution data, further statistical calculations are performed to obtain macroscopically usable characteristic parameters. Specifically, this includes: calculating the average fiber length based on the statistical distribution data of fiber length; calculating the fiber orientation utilization coefficient based on the statistical distribution data of fiber spatial angles, which is used to quantify the contribution of fiber arrangement direction to the overall strength of the material; and calculating the average fiber diameter based on the statistical distribution data of fiber diameter.

[0052] Due to limitations such as field of view and material uniformity, fiber volume fraction is difficult to obtain accurately directly through image analysis. Therefore, this embodiment determines this parameter based on a preset fiber volume acquisition method to ensure data accuracy.

[0053] Through the above methods, this embodiment can comprehensively and accurately capture key data of composite materials from macroscopic mechanical properties to microscopic geometric features, laying a data foundation for subsequent acquisition of interfacial shear strength and hypothesis verification based on the mixing law and shear hysteresis model.

[0054] Optionally, the fiber orientation utilization coefficient is obtained based on the statistical distribution data of fiber spatial angles, including: establishing a fiber angle probability density distribution function based on the statistical distribution data of fiber spatial angles; integrating the product of the fiber angle probability density distribution function and a preset projection correction coefficient to obtain the fiber orientation utilization coefficient, wherein the value of the preset projection correction coefficient is not less than zero and not greater than one.

[0055] In this embodiment, the specific method for obtaining the fiber orientation utilization coefficient is limited in order to accurately quantify the contribution of the fiber arrangement direction in space to the overall mechanical properties of the composite material under test.

[0056] Specifically: First, based on the statistical distribution data of fiber spatial angles obtained in the aforementioned steps, a probability density distribution function of fiber angles is constructed. This function can continuously and accurately describe the distribution probability of fibers within the composite material under test relative to the tensile direction (load direction) at different angles.

[0057] Secondly, a preset projection correction coefficient is introduced. This coefficient is a function or parameter related to the fiber angle, and its significance lies in characterizing the effective load-bearing component of the fiber in the load direction at a specific angle. Since the load-bearing efficiency of the fiber decreases as the angle between it and the load direction increases, the value range of this projection correction coefficient is limited to between zero and one (i.e., not less than zero and not greater than one). When the fiber is completely parallel to the tensile direction, the coefficient approaches 1, indicating the highest load-bearing efficiency; when the fiber is completely perpendicular to the tensile direction, the coefficient approaches 0, indicating the lowest load-bearing efficiency.

[0058] Finally, the product of the established fiber angle probability density distribution function and the preset projection correction coefficient is integrated. The value obtained by this integration is the final fiber orientation utilization coefficient.

[0059] In one embodiment, the projection correction factor is the cosine of the angle between the fiber and the stretching direction, the square of the cosine, or the fourth power of the cosine.

[0060] Let the fiber orientation utilization coefficient be... The angle between the fiber and the stretching direction is The fiber angle probability density distribution function is The projection correction factor is the square of the cosine of the angle between the fiber and the stretching direction. Therefore, the fiber orientation utilization factor can be expressed as: The fiber orientation utilization coefficient, as a correction factor, can objectively reflect the comprehensive influence of the actual spatial orientation distribution of fibers on the macroscopic strength of composite materials, thus providing accurate input parameters for subsequent calculation of interfacial shear strength based on the modified mixing law.

[0061] Optionally, the microstructure statistical parameters also include the fiber length utilization coefficient; the corresponding interfacial shear strength acquisition method is determined according to the preset assumptions, including: determining the acquisition method of the fiber length utilization coefficient corresponding to the preset assumptions based on the preset assumptions and the shear hysteresis model, wherein the fiber length utilization coefficient characterizes the influence of fiber length factor on interfacial shear stress in composite materials through fiber critical length and fiber average length; and the interfacial shear strength is obtained based on the modified mixing law, combined with macroscopic mechanical parameters and microstructure statistical parameters, wherein the modified mixing law is based on the mixing law, and the contribution of fiber to the tensile strength of the composite material under test is modified according to the fiber length utilization coefficient and the fiber orientation utilization coefficient.

[0062] This embodiment specifies the method for obtaining the interfacial shear strength.

[0063] Within the theoretical framework of the shear hysteresis model, the relative magnitude of the fiber's average length and critical length directly determines the stress transfer efficiency at the fiber-matrix interface. To quantify the impact of this length factor on interfacial shear stress and the overall strength of the composite material, this embodiment introduces the key parameter of "fiber length utilization coefficient".

[0064] Based on the preset assumptions set in the aforementioned steps (i.e., the relationship between the average fiber length and the critical fiber length), the corresponding formula for calculating the fiber length utilization coefficient is determined.

[0065] First, based on the shear hysteresis theory, the critical length of the fiber is obtained as follows: in, This is the critical fiber length. The average diameter of the fiber. The tensile strength of the fiber. The interfacial shear strength.

[0066] Subsequently, based on different preset assumptions (e.g., the average fiber length is greater than or less than the critical length), a fiber length utilization coefficient is obtained based on the critical fiber length. In a specific embodiment, the fiber length utilization coefficient is obtained based on the critical fiber length as follows: in, The fiber length utilization coefficient. This represents the average fiber length.

[0067] After determining the fiber length utilization coefficient, it is introduced into the mixing law together with the previously obtained fiber orientation utilization coefficient to construct a modified mixing law suitable for the composite material to be tested.

[0068] Specifically, the modified hybrid law modifies the contribution of fibers to the tensile strength of composite materials in the traditional hybrid law by introducing a "fiber strength utilization coefficient" and taking into account both length and orientation effects.

[0069] In one embodiment, based on fiber length utilization factor and fiber orientation utilization coefficient Obtain the fiber strength utilization coefficient Make corrections to the fiber strength utilization factor. The methods for obtaining it are as follows: In one embodiment, the fiber-related terms in the hybrid law are multiplied by a fiber strength utilization factor. The corrected mixture law is obtained: Based on the above embodiments, we can conclude that: In the above formula, the macroscopic mechanical parameters already include the tensile strength of the composite material being tested. Fiber tensile strength Tensile strength or yield strength of the matrix The statistical parameters of the microstructure already include the average fiber length. Fiber orientation utilization coefficient Average fiber diameter and fiber volume fraction At this point, the interfacial shear strength As the only unknown variable, it can be solved through algebraic transformations.

[0070] Further analysis reveals: This completes the entire process of determining the corresponding interface shear strength acquisition method based on preset assumptions.

[0071] Based on the method described in this embodiment, the testing and calculation of the interfacial shear strength of a certain composite material can be fully realized. For example... Figure 2 The diagram shown is a schematic representation of a specific execution flow of the method described in this embodiment.

[0072] Based on the method described in this embodiment, in a specific embodiment, for a composite material with a fiber content of 3.66 wt%, the matrix material is known to be HDPE, the fiber material is T700 grade carbon fiber, the strength of T700 fiber is 4900 MPa, the fiber diameter is 7 μm, the fiber volume fraction is 1.97%, the preparation method is GB / T 1040.2-2006 (ISO 527-2) standard, and the 1A type dog bone tensile specimen is prepared by injection molding process.

[0073] Tensile mechanical property tests were conducted on this material at a temperature of 20℃ and a tensile speed of 50 mm / min, corresponding to a tensile strain rate of [missing value]. ,like Figure 3 As shown, the average tensile strength of the composite material was 49.05 MPa, and the average yield strength of the HDPE matrix was 31.07 MPa.

[0074] Micro-CT was used to characterize the fiber network morphology in the composite material, such as... Figure 4As shown, the spatial distribution of the fibers is obtained. By statistically analyzing the spatial angles and lengths of each fiber, the probability density distribution of the fiber spatial angles is obtained, as shown below. Figure 5 As shown; the probability density distribution of fiber length is obtained, as follows. Figure 6 As shown. The orientation utilization coefficient is calculated according to the formula for fiber orientation utilization rate coefficient. The value is 0.83, and the average fiber length is 220 μm.

[0075] To calculate the fiber-matrix interfacial shear strength, it is first assumed that the average fiber length in the composite material is less than the critical fiber length. The fiber length utilization coefficient is calculated using the following formula: The formula for the provisional interfacial shear strength is as follows, and the calculated result is 36.18 MPa: Based on the assumption of the provisional interfacial shear strength, the critical fiber length in the composite material is calculated to be 437 μm. Comparing the calculated critical fiber length with the average fiber length, it was found that the average fiber length (220 μm) is less than the calculated critical fiber length (437 μm), satisfying the pre-set assumption. Therefore, the calculated provisional interfacial shear strength is the final fiber-matrix interfacial shear strength, which is 36.18 MPa in this composite material.

[0076] In another specific embodiment, for the composite material with a fiber content of 3.66 wt%, the matrix material is HDPE, the fiber material is T700 grade carbon fiber, the strength of T700 fiber is 4900 MPa, and the fiber diameter is 7 μm. The measurement conditions and the measurement results of parameters such as the mechanical properties of the composite material, the mechanical properties of the matrix, and the fiber length and angle are consistent with those in the aforementioned embodiment.

[0077] To calculate the interfacial shear strength, it is first assumed that the average fiber length in the composite material is greater than or equal to the critical fiber length. The fiber length utilization coefficient is then calculated. The provisional interfacial shear strength was calculated to be 50.94 MPa. Based on the assumption of the provisional interfacial shear strength, the critical fiber length in the composite material is calculated to be 337 μm. Comparing the calculated critical fiber length with the average fiber length, it was found that the average fiber length (220 μm) is less than the calculated critical fiber length (337 μm), which contradicts the preset assumption. Therefore, it should be assumed that the average fiber length is less than the critical fiber length, and by using the calculation steps in the aforementioned embodiment, the interfacial shear strength between the fiber and the matrix in the composite material can be obtained as 36.18 MPa.

[0078] In another specific embodiment, for the composite material with a fiber content of 6.62 wt%, the matrix material is LDPE, the fiber material is T300 fiber with a tensile strength of 2100 MPa, a fiber diameter of 7 μm, and a fiber volume fraction of 3.62%.

[0079] The composite material was prepared using a solution mixing method, and its tensile mechanical properties were tested at a temperature of 20℃ and a tensile speed of 50 mm / min. The corresponding tensile strain rate was [missing information]. The average tensile strength of the composite material was 48.26 MPa, and the average tensile strength of the LDPE matrix was 20.45 MPa.

[0080] The fiber network morphology in the composite material was characterized by Micro-CT, and the fiber orientation utilization coefficient was calculated to be 0.61, with an average fiber length of 562 μm.

[0081] To calculate the fiber-matrix interfacial shear strength, it is first assumed that the average fiber length in the composite material is less than the critical fiber length. The fiber length utilization coefficient is calculated using the following formula: The provisional interface shear strength was obtained, and the calculated result was 16.10 MPa. Based on the assumption of the provisional interfacial shear strength, the critical fiber length in the composite material is calculated to be 456 μm: Comparing the calculated critical fiber length with the average fiber length, it was found that the average fiber length (562 μm) is greater than the calculated critical fiber length (456 μm), which does not meet the pre-set assumption. This indicates that in actual materials, the average fiber length and the critical fiber length should satisfy another relationship, namely, the average fiber length is greater than or equal to the critical fiber length. Therefore, the fiber length utilization coefficient can be obtained. For cases where the average fiber length is greater than or equal to the critical fiber length, the provisional interfacial shear strength is obtained using the following method, resulting in 17.01 MPa: Based on the pre-defined assumptions corresponding to the provisional interfacial shear strength, the critical fiber length in the composite material is calculated to be 431 μm.

[0082] Comparing the calculated critical fiber length with the average fiber length, it was found that the average fiber length (562 μm) is greater than the calculated critical fiber length (431 μm), satisfying the pre-set assumption. Therefore, the interfacial shear strength between the fiber and the matrix in this composite material is 17.01 MPa.

[0083] Optionally, the method of acquiring an image of the spatial distribution of fibers in the composite material to be tested includes: acquiring an image of the spatial distribution of fibers in the composite material to be tested based on a non-destructive three-dimensional imaging method and / or a slice imaging method; a preset fiber volume acquisition method, including a process feeding and / or a matrix removal measurement method; the method further includes: processing the composite material to be tested using a high-temperature calcination method or a chemical solvent etching method.

[0084] This embodiment further specifies the methods for obtaining statistical parameters of microstructure to ensure that accurate spatial distribution characteristics and volume fraction of fibers can be obtained.

[0085] First, in order to comprehensively and accurately characterize the three-dimensional spatial distribution of fibers within the composite material, this embodiment provides two imaging methods: Non-destructive 3D imaging: This method enables tomographic scanning and 3D reconstruction of the interior of materials without damaging their physical structure. Specifically, it can employ micro-computed tomography (Micro-CT or Nano-CT) technology. Micron- or nano-scale X-rays penetrate the composite material under test, and the transmitted intensity distribution is recorded by a detector. Image processing algorithms are then used to reconstruct a high-resolution 3D image of the sample's interior. This method can clearly reveal the fiber distribution, pore size, and interfacial bonding within the material, and the tested sample can be repeatedly used for subsequent mechanical property testing.

[0086] Slice Imaging Method: This is a method for retrieving three-dimensional information from two-dimensional images. First, the composite material sample is cut, inlaid, and polished in different directions. Then, a two-dimensional image of the sample cross-section is acquired using an optical microscope (OM) or a scanning electron microscope (SEM). Based on the elliptical shape of the fibers in the cross-section, specifically using the Method of Ellipses, the spatial angular distribution of the fibers can be calculated by measuring the major axis, minor axis, and deflection angle of the ellipse.

[0087] Regarding fiber volume fraction, this embodiment provides the following two methods for obtaining it: Process feeding conversion method: In the process of composite material preparation, the mass fraction of the fiber is obtained by accurately weighing the mass of the fiber and the matrix to be tested; the volume fraction of the fiber is calculated by combining the fiber density and the matrix density through a physical conversion formula.

[0088] Matrix removal measurement method: After the composite material is prepared, the matrix material is completely removed by high-temperature calcination or chemical solvent dissolution. The mass of the remaining fibers is weighed, and the fiber volume fraction is calculated by combining the initial density of the composite sample and the fiber density.

[0089] Before acquiring images or fiber volume fraction data using the aforementioned slice imaging method or matrix removal measurement method, it may be necessary to preprocess the composite material under test to eliminate the influence of the matrix on the acquired fiber images. To address this requirement, this embodiment provides the following two methods: High-temperature calcination method: The composite material is heated to the decomposition temperature of the matrix material, causing it to undergo pyrolysis or oxidation, thereby removing the matrix.

[0090] Chemical solvent etching method: The sample is immersed in a specific chemical solvent (such as acetone, concentrated nitric acid or acid-base solution), and the matrix material is dissolved or swollen by chemical reagents to achieve the separation of fiber and matrix.

[0091] The specific experimental methods and preprocessing steps described above can effectively improve the accuracy of the extracted microstructure parameters, laying a data foundation for the subsequent determination of accurate interfacial shear strength.

[0092] Optionally, the fibers in the composite material to be tested are one of the following types: inorganic fibers, organic synthetic fibers, and natural plant fibers; the matrix in the composite material to be tested is one of thermoplastic polymers and thermosetting polymers, wherein when the matrix is ​​a thermoplastic polymer, the macroscopic mechanical parameters include the yield strength of the matrix, and when the matrix is ​​a thermosetting polymer, the macroscopic mechanical parameters include the tensile strength of the matrix.

[0093] This example suggests that the fibers in the composite material to be tested can be one of inorganic fibers, organic synthetic fibers, or natural plant fibers. Examples include any one of carbon fiber, glass fiber, basalt fiber, aramid fiber, boron fiber, silicon carbide fiber, alumina fiber, and bamboo fiber.

[0094] The matrix of the composite material to be tested is a thermoplastic polymer or a thermosetting polymer. For example, when the matrix is ​​a thermoplastic polymer, it can be one of polyethylene, polypropylene, polyamide, polyetheretherketone, polyetherimide, polyphthalamide, polyphenylene sulfide, polycarbonate, polyoxymethylene, polyethylene terephthalate, and polybutylene terephthalate; when the matrix is ​​a thermosetting polymer, it can be one of epoxy resin, phenolic resin, bismaleimide resin, unsaturated polyester resin, vinyl ester resin, cyanate ester resin, or polyurethane resin.

[0095] In one embodiment, when the matrix material is a thermoplastic polymer, the molding process of the material is selected from one or a combination of extrusion molding, injection molding, compression molding, hot pressing or continuous fiber fracture compounding molding; the adjustable process parameters include barrel temperature, mold temperature, injection pressure, holding time or screw speed.

[0096] In one embodiment, when the matrix material is a thermosetting polymer, the molding process of the material is selected from one or a combination of compression molding, resin transfer molding, vacuum-assisted resin transfer molding, prepreg placement molding, or reaction injection molding; the adjustable process parameters include curing temperature profile, curing pressure, resin injection rate, or vacuum degree.

[0097] It should be noted that, in this embodiment, yield strength is used as the macroscopic mechanical parameter because thermoplastic materials have large deformation; while for thermosetting materials, tensile strength is used as the macroscopic mechanical parameter because they have small deformation and are brittle.

[0098] Optionally, the method further includes: obtaining the macroscopic mechanical parameters and microstructural statistical parameters of the composite material under test at different ambient temperatures or different tensile rates and determining the final interfacial shear strength; statistically analyzing the final interfacial shear strength to obtain the performance of the interfacial shear strength of the composite material under test under the influence of temperature or tensile rate.

[0099] This embodiment proposes to extend and refine the aforementioned interfacial shear strength testing method in order to comprehensively evaluate the performance of composite materials under different working conditions.

[0100] Specifically, this embodiment introduces various working conditions, focusing on the impact of two key external factors—ambient temperature and loading rate (tensile rate)—on interfacial properties. By changing the ambient temperature or tensile rate, the final interfacial shear strength is obtained and statistically analyzed to acquire the interfacial shear strength performance of the composite material under the influence of temperature or tensile rate.

[0101] In one specific embodiment, for the composite material with a fiber content of 3.66 wt%, the matrix material is HDPE, the fiber material is T700 grade carbon fiber with a tensile strength of 4900 MPa and a fiber diameter of 7 μm.

[0102] The tensile speed for mechanical property testing was 0.5 mm / min, corresponding to a tensile strain rate of approximately With other parameters consistent with the aforementioned embodiments, tensile mechanical property tests were conducted at different test temperatures. The tensile strengths of the composite material at 20, 40, 60, and 80°C were 37.56, 27.44, 20.91, and 15.93 MPa, respectively, and the yield strengths of the HDPE matrix were 20.18, 14.07, 10.66, and 8.18 MPa, respectively. The final interfacial shear strengths at 20, 40, 60, and 80°C were 34.59, 26.56, 20.35, and 15.39 MPa, respectively. Therefore, the interfacial shear strength between the fiber and the matrix in the composite material at different temperatures can be measured and obtained to characterize the effect of temperature on the interfacial bonding effect between the fiber and the matrix in the composite material.

[0103] In another specific embodiment, for the composite material with a fiber content of 3.66 wt%, the matrix material is HDPE, the fiber material is T700 grade carbon fiber, its tensile strength is 4900 MPa, and the fiber diameter is 7 μm. Other parameters are consistent with those in the previous embodiments. Tensile mechanical property tests were carried out under different tensile strain rates to obtain... , , and The tensile strengths of the composite materials at the specified tensile rates were 37.56, 44.00, 49.05, and 54.42 MPa, respectively, while the yield strengths of the HDPE matrix were 20.18, 24.67, 29.17, and 32.86 MPa, respectively. , , and The fiber-matrix interfacial shear strengths at the corresponding tensile rates were 34.59, 38.56, 39.80, and 43.21 MPa, respectively. Therefore, the interfacial shear strength between the fiber and matrix in the composite material can be measured and obtained at different tensile speeds or tensile strain rates, which can be used to characterize the effect of tensile speed or tensile strain rate on the interfacial bonding effect between the fiber and matrix in the composite material.

[0104] The third embodiment of this application also proposes a device for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, such as... Figure 7 As shown, the device includes: The parameter acquisition unit 710 is used to acquire the macroscopic mechanical parameters and microstructure statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructure statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructure statistical parameters include at least the average fiber length. Assumption setting unit 720 is used to set a preset assumption about the length relationship between the average fiber length and the critical fiber length, and to determine the corresponding interface shear strength acquisition method based on the preset assumption. The interface shear strength acquisition method is determined based on the hybrid law and shear hysteresis model. The data calculation unit 730 is used to obtain the provisional interface shear strength based on the interface shear strength acquisition method, combined with macroscopic mechanical parameters and microscopic structural statistical parameters. The assumption verification unit 740 is used to obtain the critical fiber length based on the provisional interfacial shear strength and verify the preset assumption to determine the final interfacial shear strength.

[0105] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0106] The composite material interface shear strength acquisition device based on macro-micro statistics in this embodiment is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0107] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application, such as... Figure 8 As shown, the computer device includes one or more processors 810, memory 820, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 8 Take the 810 processor as an example.

[0108] The processor 810 may be a central processing unit, a network processor, or a combination thereof. The processor 810 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GPA), or any combination thereof.

[0109] The memory 820 stores instructions executable by at least one processor 810 to cause the at least one processor 810 to perform the method shown in the above embodiments.

[0110] The memory 820 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 820 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 820 may optionally include memory remotely located relative to the processor 810, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0111] The memory 820 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 820 may also include a combination of the above types of memory.

[0112] The computer device also includes a communication interface 830 for communicating with other devices or communication networks.

[0113] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0114] This application provides a computer program product including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the method of any embodiment of this application.

[0115] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

[0116] The methods, apparatus, computer devices, computer-readable storage media, or computer program products described in the above embodiments can be implemented by a computer chip or entity, or by a product having a certain function. A typical implementing device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0117] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0118] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, computer devices, computer-readable storage media, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-readable program code.

[0119] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, computer devices, computer-readable storage media, or computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0120] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0121] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0122] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0123] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of apparatus, computer equipment, computer-readable storage media, or computer program products are basically similar to the method embodiments, so the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0124] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

[0125] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, characterized in that, The method includes: Obtain the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructural statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructural statistical parameters include at least the average fiber length; A preset assumption is set regarding the length relationship between the average fiber length and the critical fiber length, and a corresponding method for obtaining the interfacial shear strength is determined based on the preset assumption. The method for obtaining the interfacial shear strength is determined based on the hybrid law and the shear hysteresis model. Based on the method for obtaining the interfacial shear strength, and in combination with the macroscopic mechanical parameters and the microscopic structural statistical parameters, a provisional interfacial shear strength is obtained. Based on the shear hysteresis model, the critical fiber length is obtained by combining the provisional interfacial shear strength, and the preset assumption is verified to determine the final interfacial shear strength.

2. The method according to claim 1, characterized in that, The step of determining the final interfacial shear strength by obtaining the fiber critical length based on the shear hysteresis model and the provisional interfacial shear strength, and verifying the preset assumptions, includes: Compare the average fiber length with the critical fiber length; If the relationship between the average fiber length and the critical fiber length does not conform to the preset assumption, a new preset assumption and corresponding interfacial shear strength acquisition method are selected, and a provisional interfacial shear strength is acquired again. Based on the shear hysteresis model, a new critical fiber length is obtained in conjunction with the re-acquired provisional interfacial shear strength, and the newly selected preset assumption is verified to determine the final interfacial shear strength. If the relationship between the average fiber length and the critical fiber length conforms to the preset assumption, the provisional interfacial shear strength is determined as the final interfacial shear strength.

3. The method according to claim 1, characterized in that, The macroscopic mechanical parameters include at least the tensile strength of the composite material under test, the tensile strength of the fibers in the composite material under test, and the tensile strength or yield strength of the matrix in the composite material under test. The microstructure statistical parameters include at least fiber length statistical distribution data, fiber spatial angle statistical distribution data, fiber diameter statistical distribution data, average fiber length, fiber orientation utilization coefficient, average fiber diameter, and fiber volume fraction. Obtaining the microstructure statistical parameters of the composite material under test includes: Obtain an image of the spatial distribution of fibers in the composite material under test; Based on the image, statistical distribution data of fiber length, fiber spatial angle, and fiber diameter are obtained. The fiber spatial angle statistical distribution data characterizes the spatial angle between the fiber and the tensile direction of the composite material under test. The average fiber length is obtained based on the statistical distribution data of fiber length, the fiber orientation utilization coefficient is obtained based on the statistical distribution data of fiber spatial angle, and the average fiber diameter is obtained based on the statistical distribution data of fiber diameter. The fiber volume fraction is obtained according to a preset fiber volume acquisition method.

4. The method according to claim 3, characterized in that, The step of obtaining the fiber orientation utilization coefficient based on the statistical distribution data of the fiber spatial angle includes: A fiber angle probability density distribution function is established based on the statistical distribution data of fiber spatial angles. The fiber orientation utilization coefficient is obtained by integrating the product of the fiber angle probability density distribution function and the preset projection correction coefficient, wherein the value of the preset projection correction coefficient is not less than zero and not greater than one.

5. The method according to claim 3, characterized in that, The microstructure statistical parameters also include the fiber length utilization coefficient; The method for determining the corresponding interface shear strength based on the preset assumption includes: Based on the preset assumptions and the shear hysteresis model, the method for obtaining the fiber length utilization coefficient corresponding to the preset assumptions is determined. The fiber length utilization coefficient characterizes the influence of fiber length factor on interfacial shear stress in composite materials through the fiber critical length and the fiber average length. Based on the modified mixing law, the interfacial shear strength is obtained by combining the macroscopic mechanical parameters and the microstructure statistical parameters. The modified mixing law is based on the mixing law and modifies the contribution of the fiber to the tensile strength of the composite material under test according to the fiber length utilization coefficient and the fiber orientation utilization coefficient.

6. The method according to claim 3, characterized in that, The step of acquiring an image of the spatial distribution of fibers in the composite material under test includes: acquiring an image of the spatial distribution of fibers in the composite material under test based on a non-destructive three-dimensional imaging method and / or a slice imaging method; The preset fiber volume acquisition method includes process feeding conversion method and / or matrix removal measurement method; The method further includes: The composite material to be tested is treated by high-temperature calcination or chemical solvent etching.

7. The method according to claim 3, characterized in that, The fibers in the composite material to be tested are one of the following types: inorganic fibers, organic synthetic fibers, and natural plant fibers; The matrix of the composite material to be tested is one of thermoplastic polymer and thermosetting polymer. When the matrix is ​​a thermoplastic polymer, the macroscopic mechanical parameters include the yield strength of the matrix. When the matrix is ​​a thermosetting polymer, the macroscopic mechanical parameters include the tensile strength of the matrix.

8. The method according to claim 1, characterized in that, The method further includes: The macroscopic mechanical parameters and microstructural statistical parameters of the composite material under test are obtained under different ambient temperatures or different tensile rates, and the final interfacial shear strength is determined. The final interfacial shear strength is statistically analyzed to obtain the performance of the interfacial shear strength of the composite material under the influence of temperature or tensile rate.

9. A device for obtaining the interfacial shear strength of composite materials based on macro-micro statistics, characterized in that, The device includes: The parameter acquisition unit is used to acquire the macroscopic mechanical parameters and microstructural statistical parameters of the composite material to be tested; wherein, the macroscopic mechanical parameters are used to characterize the macroscopic mechanical properties of the composite material to be tested, and the microstructural statistical parameters are used to characterize the spatial distribution characteristics of the fibers in the composite material to be tested, and the microstructural statistical parameters include at least the average fiber length. The assumption setting unit is used to set a preset assumption about the length relationship between the average fiber length and the critical fiber length, and to determine the corresponding interface shear strength acquisition method based on the preset assumption. The interface shear strength acquisition method is determined based on the hybrid law and the shear hysteresis model. The data calculation unit is used to obtain the provisional interface shear strength based on the interface shear strength acquisition method, combined with the macroscopic mechanical parameters and the microscopic structural statistical parameters. The assumption verification unit is used to obtain the critical fiber length based on the provisional interfacial shear strength and verify the preset assumption to determine the final interfacial shear strength.

10. A computer device, characterized in that, include: The system includes a memory and a processor, which are interconnected and communicate with each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the method for obtaining the interfacial shear strength of composite materials based on macro-micro statistics as described in any one of claims 1 to 8.

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