Ceramic matrix composite material fatigue load interface parameter optimization identification method considering multiple characteristics of hysteresis loop, medium and equipment

Abstract

The invention provides a ceramic-based composite material interface parameter optimization identification method, medium and equipment considering multiple characteristics of a hysteresis loop under fatigue load, and belongs to the field of ceramic-based composite material interface parameter identification. Comprising the following steps: carrying out a CMC fatigue test, and extracting multiple features of a hysteresis loop under different cycle numbers; deducing a theoretical expression of multiple features of the hysteresis loop in different interface debonding and slippage states; establishing an inverse function relationship between the interface shear stress and the hysteresis loop secant modulus as an interface shear stress identification function; establishing an optimization model based on an interface shear stress identification result; and solving the optimization model by adopting a genetic algorithm, and identifying the degradation rule of the interface shear stress along with the cycle index according to the optimized key influence parameters. According to the method, an interface parameter identification mechanism guided by a main feature is adopted, an optimization model compatible with multiple features of the hysteresis loop is constructed, high-precision prediction of the features of the hysteresis loop and the fatigue life is realized based on an iterative verification system, and the reasonability of an interface shear stress identification result is proved.

Description

Technical Field

[0001] This invention belongs to the field of interface parameter identification of ceramic matrix composites, and specifically relates to a method, medium and device for optimizing and identifying interface parameters of ceramic matrix composites under fatigue load, considering multiple features of hysteresis loops. Background Technology

[0002] Ceramic matrix composites (CMCs) have become the preferred material for hot-end components of aero-engines due to their high specific strength, high specific modulus, and excellent high-temperature resistance. In actual service environments, CMCs inevitably endure fatigue loads. Under fatigue loads, interfacial wear is the primary form of damage; therefore, accurately obtaining the degradation law of interfacial shear stress is crucial for accurately predicting the fatigue damage evolution process and failure life of materials.

[0003] Currently, interfacial shear stress testing methods mainly include direct and indirect methods. The direct method is primarily based on nanoindentation technology, obtaining interfacial parameters under specific conditions through operations such as fiber insertion and extraction. Therefore, the measurement temperature of the direct method is limited by the operating temperature of the nanoindentation testing instrument, with the highest current measurement temperature being 800℃. Furthermore, the direct method requires stopping the test for different numbers of cycles and preparing test samples by destroying the specimen; therefore, for the same specimen, only test results at a specific number of cycles can be obtained. Since CMC properties exhibit significant dispersion, the measurement results for different specimens are discontinuous, making it difficult to analyze the degradation patterns of interfacial properties at different cycle numbers; that is, the results of the direct method lack in-situ and continuity. Since ceramic matrix composites are mainly used at high temperatures, in-situ measurement of interfacial shear stress at high temperatures requires further exploration.

[0004] To address the limitations of direct methods, indirect methods have seen some development. Their core idea is to deduce the magnitude of interfacial shear stress by analyzing the hysteresis behavior of materials under fatigue loading, based on theoretical models. Commonly used indirect methods primarily identify interfacial parameters based on a single or at most two hysteresis features. However, accurately describing hysteresis loops generally requires considering multiple features such as their location, slope, and magnitude. Therefore, existing indirect methods only reflect the fatigue behavior of the CMC portion, and the identification results have certain limitations.

[0005] Furthermore, the indirect method assumes no fiber bundle failure during fatigue loading; therefore, the identification results may not be usable for accurately predicting the fatigue life of CMCs. Finally, the indirect method typically uses a theoretical model for reverse identification, and its results are influenced by model parameters. Since CMCs exhibit significant dispersion, determining appropriate model parameters for a specific specimen is crucial to ensuring the accuracy of interface shear stress identification. In summary, for the problem of fatigue parameter identification in specific CMC specimens, it is necessary to fully consider the material's hysteresis behavior, damage mechanism, and material dispersion to improve the reliability of the identification results. Therefore, the method for identifying interface parameters of CMCs under fatigue loading still needs further improvement. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method, medium, and device for optimizing and identifying interface parameters of ceramic matrix composites under fatigue loads, taking into account the multiple characteristics of hysteresis loops.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for optimizing and identifying interface parameters of ceramic matrix composites under fatigue load, considering multiple features of hysteresis loops, comprising the following steps:

[0009] Step 1: Conduct CMC fatigue tests to obtain fatigue hysteresis curves and extract multiple features of the hysteresis loop under different cycle numbers, including the maximum strain of the hysteresis loop, the secant modulus of the hysteresis loop, and the area of ​​the hysteresis loop.

[0010] Step 2: Based on the shear hysteresis model, derive the theoretical expressions for the multiple characteristics of the hysteresis loop under different interface deadhesion and slip states;

[0011] Step 3: Based on the theoretical expression of the multiple characteristics of the hysteresis loop in Step 2, establish the inverse functional relationship between the interface shear stress and the secant modulus of the hysteresis loop, and use it as the interface shear stress identification function.

[0012] Step 4: Based on the shear hysteresis model and combined with the component damage model such as fiber failure, calculate the percentage of fiber failure under the maximum number of test cycles;

[0013] Step 5: Based on the interface shear stress identification function in Step 3, the differences between the theoretical values ​​and experimental results of the hysteresis loop multi-features and the differences between the fiber failure percentage and the critical value under the maximum number of test cycles are used as optimization objectives. Key influencing parameters in the shear hysteresis model are selected as optimization variables to establish an interface shear stress optimization model that considers the multi-features of the hysteresis loop, failure lifetime and material dispersion.

[0014] Step 6: Use a genetic algorithm to solve the optimization model, and identify the degradation law of interface shear stress with the number of cycles based on the optimized key influencing parameters.

[0015] Optionally, in step 2, the theoretical expression for the multiple features of the hysteresis loop is as follows:

[0016] 1) The maximum strain of the hysteresis loop when the interface is partially or completely debonded. The expression is:

[0017]

[0018] In the formula, L d The expression for C1 represents the theoretical interface debonding length. v f1 E represents the percentage of remaining intact fibers. f E represents the fiber's elastic modulus. c σ represents the CMC elastic modulus. max The maximum fatigue stress is represented by L, and the average matrix crack spacing is represented by L.

[0019] 2) When the interface partially slides, if L / 2 > y max1 , where y max1 =C1Δσ / (2tanθ1), where Δσ represents the difference between the maximum and minimum applied stress, and tanθ1 is expressed as 2τ i / r f , τ i Represents the interfacial shear stress, r f Let K represent the fiber radius, then the hysteresis loop modulus is K. m The expression is:

[0020]

[0021] When the interface is fully slid, if y is satisfied max1 If ≥L / 2, then the hysteresis loop secant modulus K m The expression is:

[0022]

[0023] 3) When the interface partially slides, if L / 2 > y max1 Then the area S of the hysteresis loop m The expression is:

[0024]

[0025] When the interface is fully slidable, if L / 2 ≤ y max1 If L < L, then the area of ​​the hysteresis loop S m The expression is:

[0026]

[0027] When the interface is fully slid, if y is satisfied max1 If L ≥ L, then the area S of the hysteresis loop m The expression is:

[0028]

[0029] Optionally, in step 3, the inverse functional relationship between the interface shear stress and the hysteresis loop secant modulus is as follows:

[0030] When the interface partially slips, the relationship between the interface shear stress and the hysteresis loop secant modulus is as follows:

[0031]

[0032] When the interface slips completely, the relationship between the interface shear stress and the hysteresis loop secant modulus is as follows:

[0033]

[0034] Optionally, in step 4, the calculation of the fiber failure percentage under the maximum number of test cycles is as follows:

[0035] For each cycle, the percentage of fiber failure is determined by the Weibull distribution function, expressed as:

[0036]

[0037] In the formula, The percentage of fiber failure is given, and L represents the average matrix crack spacing. m f For fiber failure, Weibull modulus and coefficient, σ f (x) represents the fiber stress, expressed as:

[0038]

[0039] In the formula, v f1 The expression for tanθ1 represents the percentage of intact fibers remaining, x represents the distance from the crack plane, and tanθ1 is expressed as 2τ. i / r f , τ i Represents the interfacial shear stress, r f L represents the fiber radius. d E represents the theoretical interface debonding length. f E represents the fiber's elastic modulus. c σ represents the CMC elastic modulus. max V represents the maximum fatigue stress. m E represents the volume fraction of the matrix. m α represents the elastic modulus of the matrix. m and α fThese represent the coefficients of thermal expansion of the fiber and the matrix, respectively, and ΔT represents the difference between the ambient temperature and the preparation temperature.

[0040] Fiber strength after degradation at different cycle numbers Described by the following empirical formula:

[0041]

[0042] In the formula, N represents the cycle number. The degradation coefficient and the exponent;

[0043] The fiber strength after degradation at different cycle numbers calculated based on empirical formulas is substituted into the expression for fiber failure percentage to update the fiber failure percentage at different cycle numbers, thereby obtaining the fiber failure percentage at the maximum number of test cycles.

[0044] Optionally, in step 5, the functional expression of the optimization objective is:

[0045]

[0046] In the formula, α1 and α2 are weighting coefficients. Predicted percentage of fiber failure under maximum test cycle number With critical value The relative error, Δe H The weighted sum of the maximum strain of the hysteresis loop and the maximum relative error of the hysteresis loop area over all cycles is expressed as:

[0047]

[0048] In the formula, β1 and β2 represent weighting coefficients. Let represent the calculated results of the maximum strain and the area of ​​the hysteresis loop at the i-th cycle number, respectively. N represents the calculated maximum strain of the hysteresis loop and the experimental result of the hysteresis loop area at the i-th cycle number, respectively. max This indicates the maximum number of test cycles.

[0049] Optionally, in step 5, the optimization variable is selected as: fiber elastic modulus E. f With the matrix elastic modulus E m Initial fiber percentage Weibull modulus of matrix crack Matrix saturation crack spacing L sat Fiber strength degradation coefficient With index

[0050] In a second aspect, the present invention provides a computer-readable storage medium storing a computer program that causes a computer to execute the interface parameter optimization and identification method for ceramic matrix composites under fatigue load, considering multiple features of hysteresis loops, as described in the first aspect.

[0051] Thirdly, the present invention provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the method for optimizing and identifying interface parameters of ceramic matrix composites under fatigue load, considering multiple features of hysteresis loops, as described in the first aspect.

[0052] The beneficial effects of this invention are:

[0053] 1. Interface parameter identification mechanism guided by main features: Based on the shear hysteresis model, the multi-feature expression of the hysteresis loop under different interface states is derived, and the interface shear stress is identified by the secant modulus as the main parameter.

[0054] 2. Optimization model compatible with multiple features of hysteresis loop: Substitute the identified interface shear stress into the theoretical model to calculate the fiber failure percentage. Take the theoretical-experimental difference between multiple features of hysteresis loop and fiber failure percentage as the optimization target. Combine genetic algorithm to optimize the key parameters of the shear hysteresis model and improve the accuracy of interface shear stress identification results.

[0055] 3. Iterative verification system: Based on the optimization results, the degradation law of interface shear stress and the percentage of fiber failure are calculated, realizing high-precision prediction of hysteresis loop characteristics and fatigue life, proving the rationality of the interface shear stress identification results. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of multiple features of a hysteresis loop.

[0057] Figure 2a The results are experimental results showing the maximum strain of the hysteresis loop as a function of the number of cycles.

[0058] Figure 2b The results are experimental findings on the variation of the hysteresis loop secant modulus with the number of cycles.

[0059] Figure 2c This is the experimental result of the hysteresis loop area varying with the number of cycles.

[0060] Figure 3 This is a schematic diagram of fiber stress distribution under different interface debonding and slip states.

[0061] Figure 4 This is a flowchart for interface shear stress identification and optimization.

[0062] Figure 5 This is the result of interface shear stress identification. Detailed Implementation

[0063] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0064] In one embodiment, the present invention proposes a method for optimizing and identifying interface parameters of ceramic matrix composites under fatigue load, considering multiple features of hysteresis loops, comprising the following steps:

[0065] Step 1: Conduct CMC fatigue tests to obtain fatigue hysteresis curves and extract hysteresis characteristics under different cycle numbers.

[0066] CMC fatigue tests were conducted to determine the peak fatigue stress based on the tensile strength of the CMC at the corresponding ambient temperature. The peak fatigue stress must be greater than the proportional limit stress to ensure that the material undergoes damage behaviors such as matrix cracking, interfacial debonding, and wear during fatigue, thus generating hysteresis behavior. Force-displacement data of the hysteresis loop at different cycle numbers were acquired using extensometers or displacement and force sensors integrated into the testing machine. Based on the specimen length and cross-sectional dimensions, the force-displacement data of the hysteresis loop was converted into stress-strain data. Three key characteristic parameters of the hysteresis loop were extracted: maximum strain (strain corresponding to the peak stress), secant modulus (ratio of the difference between the maximum and minimum stresses of the hysteresis loop to its corresponding strain difference), and hysteresis loop area (area of ​​the region contained within the hysteresis loop). This yielded a multi-characteristic parameter dataset of the hysteresis loop at different cycle numbers.

[0067] In this example, the test temperature was 1400℃. Based on the tensile curve, the maximum material strength was measured to be 200 MPa, and the peak fatigue stress was set to 120 MPa (stress ratio 0.1). A schematic diagram of the hysteresis loop characteristic parameters (maximum strain, secant modulus, and area) and their variation with the number of cycles is shown below. Figure 1 and Figures 2a-2c As shown.

[0068] Step 2: Based on the shear hysteresis model, derive the theoretical expressions for the multiple characteristics of the hysteresis loop under different interface deadhesion and slip states.

[0069] Shear hysteresis models have been proven to be effective micromechanical models for describing unidirectional CMC fatigue hysteresis behavior, such as... Figure 3 As shown. Based on the shear hysteresis model, theoretical expressions for the multiple features of the hysteresis loop under different interface states can be obtained, as follows:

[0070] (1) Theoretical expression for maximum strain of hysteresis loop:

[0071] Regardless of whether the interface is in a partially or completely debonded state, the expression for the maximum strain of the hysteresis loop is as follows:

[0072]

[0073] The explanations for the different parameters are as follows:

[0074] Maximum strain of hysteresis loop calculated based on shear hysteresis model;

[0075] C1: The expression is

[0076] v f1 The percentage of remaining intact fibers is expressed as follows:

[0077] Indicates the percentage of fiber failure;

[0078] Initial fiber percentage;

[0079] E f E m : Indicates the elastic modulus of the fiber and the matrix;

[0080] E c : Represents the CMC elastic modulus, expressed as: The influence of fiber failure percentage was taken into account;

[0081] tanθ1: The expression is 2τ i / r f ;

[0082] τ i : Represents interfacial shear stress;

[0083] r f : Indicates fiber radius;

[0084] Δσ: Represents the difference between the maximum and minimum applied stress, or the maximum stress σ. max The product of stress ratio R1;

[0085] L: Represents the average matrix crack spacing, which can usually be determined using the Weill distribution function, as shown in the following expression:

[0086]

[0087] Among them, L sat σ represents the crack spacing in the saturated matrix. i This represents the external stress, specifically the maximum fatigue stress σ. max , m0 represents the Weibull modulus of the matrix crack and its coefficient. x1 represents a coefficient related to whether the interface is completely debonded, and its expression is shown below:

[0088]

[0089] Among them, L d The theoretical debonding length is expressed as: The fiber stress in the bonded zone is expressed as σ. max E f / E c +(α m -α f )ΔTv m E f E m / E c α m and α f This represents the coefficient of thermal expansion of the fiber and the matrix.

[0090] (2) Theoretical expression for the hysteresis secant modulus:

[0091] When the interface partially slips, the interface debonding length and the average matrix crack spacing satisfy L / 2 > y. max1 The inequality relationship, where y max1 The expression is y max1 =C1Δσ / (2tanθ1). At this point, the expression for the hysteresis loop secant modulus is as follows:

[0092]

[0093] When the interface completely slips, the interface debonding length and the average matrix crack spacing satisfy y max1 The inequality relationship is ≥L / 2. In this case, the expression for the hysteresis loop secant modulus is as follows:

[0094]

[0095] (3) Theoretical expression for the area of ​​hysteresis loop:

[0096] When the interface partially slips, the average matrix crack spacing and the length of the reverse slip zone at the interface satisfy L / 2 > y. max1 The inequality, where y max1 The expression is y max1 =C1Δσ / (2tanθ1), at this time, the hysteresis loop area theory S m The expression is as follows:

[0097]

[0098] When the interface is fully slipped, the average matrix crack spacing and the length of the reverse slip zone at the interface satisfy L / 2 ≤ y. max1 The inequality < L, in this case, the theoretical expression for the area of ​​the hysteresis loop is as follows:

[0099]

[0100] When the interface is fully slipped, the average matrix crack spacing and the length of the reverse slip zone of the interface satisfy y max1 For inequalities ≥ L, the theoretical expression for the area of ​​the hysteresis loop is as follows:

[0101]

[0102] Thus far, based on the shear hysteresis model, theoretical expressions for multiple characteristics (maximum strain, secant modulus, and hysteresis loop area) of the hysteresis loop under different interface debonding and slip states have been established.

[0103] In this example, some parameters of the shear lag model are shown in Table 1.

[0104] Table 1. Some parameters of the shear lag model

[0105]

[0106] Step 3: Based on Step 2, establish the inverse functional relationship between the interface shear stress and the hysteresis loop secant modulus, which will serve as the interface shear stress identification function.

[0107] Based on sampling and correlation analysis using theoretical formulas, it is found that among the three hysteresis loop characteristic parameters, the correlation between the secant modulus of the hysteresis loop and the interface shear stress is significantly higher than that of the other parameters. If multiple characteristic parameters are used simultaneously to identify the interface shear stress, the results may be unstable due to the coupling effect between the parameters. Therefore, this embodiment selects the secant modulus as the core identification parameter, and the other characteristic parameters are only used for result verification and constraint, thereby avoiding interference from multiple parameters while ensuring accuracy.

[0108] Based on the theoretical model in step 2, the inverse functional relationship between the interface shear stress and the secant modulus is established, and the specific method is as follows:

[0109] When the interface partially slips, the relationship between the interface shear stress and the hysteresis loop secant modulus can be obtained through formula (4) as follows:

[0110]

[0111] When the interface is fully slipped, the relationship between the interface shear stress and the hysteresis loop secant modulus can be obtained through formula (5) as follows:

[0112]

[0113] Therefore, by substituting the hysteresis loop secant modulus and related parameters under different cycle numbers into formulas (4) and (5), the variation law of interface shear stress with the number of cycles can be identified.

[0114] Step 4: Based on the shear lag model and combined with the fiber failure and other component damage models, calculate the percentage of fiber failure under the maximum number of test cycles.

[0115] For each cycle, the percentage of fiber failure is highest at the peak fatigue stress. The percentage of fiber failure is determined by the Weibull distribution function, the specific expression of which is shown below:

[0116]

[0117] in, m f For fiber failure, Weibull modulus and coefficient, σ f (x) represents the fiber stress, and its expression is shown below:

[0118]

[0119] Where, α m α f These represent the coefficients of thermal expansion of the fiber and the matrix, respectively.

[0120] Furthermore, the relative sliding between the fiber and the matrix during fatigue not only reduces the interfacial shear stress but also induces fiber strength degradation. The degradation law of fiber strength with the number of cycles is described by the following empirical formula:

[0121]

[0122] in, As the degradation coefficient and exponent, the fiber strength after degradation under different cycle numbers calculated by formula (13) is substituted into formula (11) to update the fiber failure percentage under different cycles. This can then be substituted into the formula shown in step 3 to identify the interfacial shear stress under different cycle numbers and calculate the corresponding hysteresis loop multi-characteristic parameters. Finally, the calculation result of the fiber failure percentage under the maximum number of test cycles is obtained.

[0123] Step 5: Based on the interfacial shear stress identification results in Step 3, establish an optimization model. The differences between the theoretical and experimental values ​​of the hysteresis loop multi-features, and the differences between the fiber failure percentage and the critical value at the maximum number of test cycles, are used as optimization objectives. Key influencing parameters in the shear hysteresis model are selected as optimization variables to establish an interfacial shear stress optimization identification model that considers hysteresis multi-features, failure lifetime, and material dispersion.

[0124] In this embodiment, due to the large number of parameters required by the shear hysteresis model and the significant dispersion of CMC performance, the identification process needs to be constrained by combining multiple characteristic parameters of the hysteresis loop and fatigue life to ensure the reliability of the interface shear stress identification results. Therefore, an optimization model is established: the parameters to be identified are substituted into the shear hysteresis model, the theoretical values ​​of the multiple characteristics of the hysteresis loop and the fiber failure percentage are calculated respectively, and compared with experimental results, with minimizing the error as the optimization objective. The optimization objective function expression is as follows:

[0125]

[0126] Where α1 and α2 are weighting coefficients. The relative error between the predicted percentage of fiber failure at the maximum number of test cycles and the critical value is expressed as follows: Δe represents the percentage of critical fiber failure. H The weighted sum of the maximum relative errors of each characteristic (area, maximum strain) of the hysteresis loop over all cycle numbers is expressed as:

[0127]

[0128] Where β1 and β2 represent weighting coefficients. Let represent the calculated results of the maximum strain and the area of ​​the hysteresis loop at the i-th cycle number, respectively. N represents the calculated maximum strain of the hysteresis loop and the experimental result of the hysteresis loop area at the i-th cycle number, respectively. max This represents the maximum number of test cycles. The optimized variable is selected as: fiber elastic modulus E. f With the matrix elastic modulus E m Initial fiber percentage Weibull modulus of matrix crack Matrix saturation crack spacing L sat Fiber strength degradation coefficient With index

[0129] In this embodiment, α1 and α2 are set to 0.4 and 0.6, respectively, and β1 and β2 are set to 0.4 and 0.6, respectively. The optimization process is as follows: Figure 4 As shown.

[0130] Step 6: Use a genetic algorithm for optimization, and substitute the optimization results into steps 3 and 4 to identify the degradation law of interface shear stress with the number of cycles.

[0131] This embodiment employs a genetic algorithm to solve the aforementioned optimization model. The optimized parameters are substituted into the shear hysteresis model, and combined with the functional relationship between the interfacial shear stress and the secant modulus of the hysteresis loop in step 3, the fiber failure percentage under different cycle numbers is iteratively identified. Simultaneously, the values ​​in step 3 are dynamically updated based on the fiber failure percentage calculated in step 4. Finally, by integrating the multiple characteristics of the hysteresis loop, fatigue life constraints, and the influence of material dispersion, a physically plausible interfacial shear stress degradation law is obtained.

[0132] In this embodiment, the selection and identification results of the optimization variables are shown in Table 2. Substituting the optimization results into steps 3 and 4, the variation law of interface shear stress with the number of cycles can be obtained ( Figure 5 Based on this, the average errors in the predicted maximum strain and secant modulus of the hysteresis loop are 9.94% and 8.09%, respectively, and the predicted error in the percentage of fiber failure under the maximum number of failure cycles is 6.29%. The overall error is small, indicating that the interfacial shear stress identification results have high reliability.

[0133] Table 2 Optimization results of input parameters for the shearing model

[0134]

[0135] In another embodiment, the present invention provides a computer-readable storage medium storing a computer program that causes a computer to execute the interface parameter optimization and identification method for ceramic matrix composites under fatigue load, considering the multiple features of hysteresis loops, as described in the foregoing embodiments.

[0136] In another embodiment, the present invention proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the interface parameter optimization and identification method for ceramic matrix composites under fatigue load considering multiple features of hysteresis loops as described in the foregoing embodiment.

[0137] In the embodiments disclosed in this application, a computer storage medium may be a tangible medium that may contain or store programs for use by or in conjunction with an instruction execution system, apparatus, or device. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of computer storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0138] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0139] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features, characterized in that, The method comprises the following steps: Step 1: CMC fatigue test is carried out to obtain a fatigue hysteresis curve, and a plurality of hysteresis loop characteristics at different cycle numbers are extracted, including a maximum strain of the hysteresis loop, a secant modulus of the hysteresis loop and an area of the hysteresis loop; Step 2: Based on a shear hysteresis model, theoretical expressions of the plurality of hysteresis loop characteristics at different interface debonding and sliding states are derived; Step 3: According to the theoretical expressions of the plurality of hysteresis loop characteristics in Step 2, an inverse function relationship between the interface shear stress and the secant modulus of the hysteresis loop is established as an interface shear stress identification function; Step 4: Based on the shear hysteresis model, a fiber failure percentage at the maximum test cycle number is calculated in combination with a component damage model such as fiber failure; Step 5: Based on the interface shear stress identification function in Step 3, differences between the theoretical values of the plurality of hysteresis loop characteristics and the test results, and differences between the fiber failure percentage at the maximum test cycle number and a critical value are taken as optimization objectives, key influence parameters in the shear hysteresis model are selected as optimization variables, and an interface shear stress optimization model considering the plurality of hysteresis loop characteristics, failure life and material dispersion is established; Step 6: The optimization model is solved by using a genetic algorithm, and the degradation law of the interface shear stress with the cycle number is identified according to the optimized key influence parameters.

2. The method of claim 1, wherein the method is a method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features. In Step 2, the theoretical expressions of the plurality of hysteresis loop characteristics are as follows: 1) Maximum strain of the hysteresis loop when the interface is partially debonded or fully debonded The expression is: where L d represents the theoretical interfacial debonding length, C1is expressed as 1 / v f1 -E f / E c , v f1 represents the percentage of remaining intact fibers, E f represents the fiber elastic modulus, E c represents the CMC elastic modulus, σ max represents the fatigue maximum stress, L represents the average matrix crack spacing; 2) When the interface part slips, if L / 2 > y max1 , where y max1 = C1Δσ / (2 tan θ1), Δσ represents the difference between the maximum and minimum loading stresses, tan θ1 is expressed as 2τ i / r f , τ i represents the interfacial shear stress, and r f represents the fiber radius, then the expression of the hysteresis loop secant modulus K m is: When the interface is completely slipped, if y max1 ≥ L / 2, the expression of the hysteresis loop cutting line modulus K m is: 3) When the interface part slips, if L / 2 > y max1 , the hysteresis loop area S m is expressed as: When the interface completely slips, if L / 2≤y max1 <L, the expression of the hysteresis loop area S m is: When the interface completely slips, if y max1 ≥ L, the hysteresis loop area S m is expressed as:

3. The method of claim 2, wherein the method is a method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features. In Step 3, the inverse function relationship between the interface shear stress and the secant modulus of the hysteresis loop is as follows: When the interface partially slips, the relationship between the interface shear stress and the secant modulus of the hysteresis loop is: When the interface completely slips, the relationship between the interface shear stress and the secant modulus of the hysteresis loop is:

4. The method of claim 1, wherein the method is a method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features. In Step 4, the fiber failure percentage at the maximum test cycle number is calculated as follows: For each cycle, the fiber failure percentage is determined by a Weibull distribution function, and the expression is as follows: where d f1 is the percentage of fiber failure, L is the average matrix crack spacing, σ f0 is the fiber stress, and f is the fiber failure Weibull modulus and coefficient, σ f (x) is the fiber stress, expressed as: where v f1 represents the percentage of residual intact fibers, x represents the position from the crack plane, tanθ1is expressed as 2τ i / r f , τ i represents the interfacial shear stress, r f represents the fiber radius, L d represents the theoretical interfacial debonding length, E f represents the fiber elastic modulus, E c represents the CMC elastic modulus, σ max represents the fatigue maximum stress, v m represents the volume fraction of the matrix, E m represents the matrix elastic modulus, α m and α f respectively represent the thermal expansion coefficients of the fiber and the matrix, and ΔT represents the difference between the environmental temperature and the preparation temperature. Fiber strength after degradation at different cycle numbers Described by the following empirical equation: In the formula, N represents the number of cycles, are the degradation coefficient and the exponent, respectively. The fiber strength at different cycle numbers after degradation calculated according to an empirical formula is brought into the expression of the fiber failure percentage, the fiber failure percentages at different cycle numbers are updated, and then the fiber failure percentage at the maximum test cycle number is obtained.

5. The method of claim 2, wherein the method is a method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features, characterized in that: In Step 5, the function expression of the optimization objective is as follows: wherein α1, α2 are weighting factors, Percentage of fiber failure prediction results under the maximum number of test cycles Relative error, Δe, with respect to the critical value H The maximum strain of the hysteresis loop and the maximum relative error of the hysteresis loop area under all cycle numbers are weighted and expressed as:​ In the formula, β1, β2 represent weighting coefficients, respectively represent the maximum strain calculation result and the hysteresis loop area calculation result under the i th cycle number, respectively represent the maximum strain calculation result and the hysteresis loop area calculation result under the i th cycle number, max N represents the maximum test cycle number.

6. The method of claim 5, wherein the method is a method for interface parameter optimization identification of ceramic matrix composites under fatigue load considering hysteresis loop multi-features, characterized in that: In step 5, the optimization variable is chosen to be: fiber elastic modulus E f with matrix elastic modulus E m , initial fiber percentage matrix crack Weibull modulus matrix saturated crack spacing L sat , fiber strength degradation coefficient with exponent 7. A computer readable storage medium storing a computer program, characterized in that, The computer program enables the computer to execute the interface parameter optimization identification method for ceramic matrix composite materials under fatigue load considering the plurality of hysteresis loop characteristics.

8. An electronic device, comprising: It comprises: a memory, a processor and a computer program stored in the memory and capable of running on the processor, when the processor executes the computer program, the interface parameter optimization identification method for ceramic matrix composite materials under fatigue load considering the plurality of hysteresis loop characteristics is realized.

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