Methods, apparatus and related equipment for predicting fatigue crack propagation life of metallic materials

Abstract

This invention provides a method, apparatus, and related equipment for predicting the fatigue crack propagation life of metallic materials. The method involves determining the optimal residual stress distribution function and its coefficients for the tested metallic material; calculating the residual stress intensity factor of the tested metallic material based on the optimal residual stress distribution function and its coefficients; obtaining the first crack propagation rate and stress intensity factor range of the corresponding parent material for the tested metallic material; calculating the Walker model constant value based on the first crack propagation rate and stress intensity factor range; calculating the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and stress intensity factor range; and using the Walker model constant value, effective stress intensity factor range, and effective stress ratio, calculating the predicted values ​​of the second crack propagation rate and crack propagation life of the tested metallic material. This invention can accurately and practically predict the fatigue crack propagation life of metallic materials in a residual stress field.

Description

Technical Field

[0001] This invention relates to the field of materials science and engineering application technology, and more specifically, to a method, apparatus and related equipment for predicting fatigue crack propagation life of metallic materials. Background Technology

[0002] In engineering, on the one hand, typical welding processes often introduce residual stress into metallic materials; on the other hand, due to surface integrity requirements, surface strengthening is often applied to stress concentration areas or life-sensitive zones to improve fatigue life. Both welding and surface strengthening methods introduce residual stress, altering surface integrity characteristics such as material morphology and microstructure, thus affecting the fatigue performance of the wheel. Furthermore, due to the introduction of residual stress, traditional fatigue life prediction methods are no longer applicable. Currently, a commonly used method is to conduct extensive experiments and perform statistical analysis of fatigue life, providing a fatigue life prediction based on statistical theory. Alternatively, finite element simulation can be used to establish a life model for simple specimens, but this is limited to the research stage. The first method requires repeated experiments, and predicting life based on existing data has significant limitations if experimental conditions change. The second method, from the perspective of finite element models, requires simplification of complex situations, and before establishing a simulation model, the importance of simplification factors needs to be determined, requiring a more comprehensive and systematic analysis.

[0003] With the continuous improvement of welding processes and surface strengthening technologies, more and more engineers are focusing on the research field of the impact of residual stress on fatigue life. Based on surface integrity and service life requirements, and considering the influence of residual stress, this study provides support for damage tolerance analysis and structural integrity evaluation of structures containing residual stress. Summary of the Invention

[0004] In view of this, to solve the above problems, the present invention provides a method, apparatus, and related equipment for predicting the fatigue crack propagation life of metallic materials, the technical solution of which is as follows:

[0005] A method for predicting the fatigue crack propagation life of a metallic material, the method comprising:

[0006] Determine the optimal residual stress distribution function of the metal material to be tested, and the coefficient values ​​of the optimal residual stress distribution function;

[0007] Based on the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function, the residual stress intensity factor of the tested metallic material is calculated;

[0008] Obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the metal material under test;

[0009] The Walker model constant is calculated based on the first crack propagation rate and the stress intensity factor range, and the effective stress intensity factor range and effective stress ratio are calculated based on the residual stress intensity factor and the stress intensity factor range.

[0010] Using the Walker model constants, the effective stress intensity factor range, and the effective stress ratio, the predicted values ​​of the second crack propagation rate and crack propagation life of the tested metallic material are calculated.

[0011] Preferably, determining the optimal residual stress distribution function of the tested metallic material and the coefficient values ​​of the optimal residual stress distribution function includes:

[0012] Obtain the residual stress introduction method corresponding to the metal material under test, as well as the actual thickness of the metal material under test;

[0013] Multiple residual stress distribution functions are determined based on the described residual stress introduction method;

[0014] The residual stress distribution functions are tested using residual stress test information that matches the actual thickness.

[0015] Based on the test results, the optimal residual stress distribution function is selected from the multiple residual stress distribution functions, and the coefficient value of the optimal residual stress distribution function is determined.

[0016] Preferably, obtaining the range of the first crack propagation rate and stress intensity factor of the parent material corresponding to the tested metallic material includes:

[0017] Crack propagation tests were conducted on the base material corresponding to the metal material under test under different stress ratios to obtain the first crack propagation rate and stress intensity factor range of the base material corresponding to the metal material under test.

[0018] Preferably, the step of calculating the effective stress intensity factor range and the effective stress ratio based on the residual stress intensity factor and the stress intensity factor range includes:

[0019] The residual stress intensity factor and the stress intensity factor range are processed by superposition method or Newman crack closure model to obtain effective stress intensity factor range and effective stress ratio.

[0020] A fatigue crack propagation life prediction device for metallic materials, the device comprising:

[0021] The function determination module is used to determine the optimal residual stress distribution function of the metal material under test, and the coefficient values ​​of the optimal residual stress distribution function;

[0022] The factor calculation module is used to calculate the residual stress intensity factor of the metal material under test based on the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function.

[0023] The life calculation module is used to obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the metal material under test; calculate the Walker model constant value based on the first crack propagation rate and the stress intensity factor range; and calculate the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and the stress intensity factor range; and calculate the predicted values ​​of the second crack propagation rate and crack propagation life of the metal material under test using the Walker model constant value, the effective stress intensity factor range, and the effective stress ratio.

[0024] Preferably, the function determination module is specifically used for:

[0025] The residual stress introduction method and the actual thickness of the metal material under test are obtained; multiple residual stress distribution functions are determined according to the residual stress introduction method; the multiple residual stress distribution functions are tested using residual stress test information that matches the actual thickness; the optimal residual stress distribution function is selected from the multiple residual stress distribution functions based on the test results, and the coefficient value of the optimal residual stress distribution function is determined.

[0026] Preferably, the lifetime calculation module used to obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the tested metallic material is specifically used for:

[0027] Crack propagation tests were conducted on the base material corresponding to the metal material under test under different stress ratios to obtain the first crack propagation rate and stress intensity factor range of the base material corresponding to the metal material under test.

[0028] Preferably, the life calculation module for calculating the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and the stress intensity factor range is specifically used for:

[0029] The residual stress intensity factor and the stress intensity factor range are processed by superposition method or Newman crack closure model to obtain effective stress intensity factor range and effective stress ratio.

[0030] An electronic device includes: at least one memory and at least one processor; the memory stores an application program, and the processor calls the application program stored in the memory, the application program being used to implement the fatigue crack propagation life prediction method for metallic materials.

[0031] A storage medium storing computer program code, which, when executed, implements the fatigue crack propagation life prediction method for metallic materials.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0033] This invention provides a method, apparatus, and related equipment for predicting the fatigue crack propagation life of metallic materials. First, the optimal residual stress distribution function and its coefficient values ​​for the metallic material under test are determined. Then, the residual stress intensity factor of the metallic material under test is calculated based on the optimal residual stress distribution function and its coefficient values. Further, the first crack propagation rate and stress intensity factor range of the corresponding parent material of the metallic material under test are obtained, and the Walker model constant is calculated based on the first crack propagation rate and stress intensity factor range. The effective stress intensity factor range and effective stress ratio are calculated based on the residual stress intensity factor and stress intensity factor range. Finally, using the Walker model constant, effective stress intensity factor range, and effective stress ratio, the predicted values ​​of the second crack propagation rate and crack propagation life of the metallic material under test are calculated. Based on this, this invention can accurately and practically predict the fatigue crack propagation life of metallic materials in a residual stress field. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0035] Figure 1 A flowchart of a method for predicting fatigue crack propagation life of metallic materials provided in an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of three residual stress distribution curves provided in the embodiments of the present invention;

[0037] Figure 3 This is a schematic diagram illustrating the effect of residual stress on the effective stress intensity factor provided in an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram illustrating the effect of residual stress on effective specific force provided in an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram illustrating the effect of residual stress on crack propagation rate provided in an embodiment of the present invention.

[0040] Figure 6This is a schematic diagram of the structure of the fatigue crack propagation life prediction device for metallic materials provided in an embodiment of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] See Figure 1 , Figure 1 A flowchart illustrating the method for predicting fatigue crack propagation life of metallic materials provided in this embodiment of the invention. Figure 1 As shown, the method for predicting the fatigue crack propagation life of this metallic material includes the following steps:

[0044] S10, determine the optimal residual stress distribution function of the metal material to be tested, and the coefficient values ​​of the optimal residual stress distribution function.

[0045] In this embodiment of the invention, considering the residual stress fields introduced by different processes and surface treatments, the residual stress distribution of the tested metallic material is analyzed to obtain its optimal residual stress distribution function. Specifically, a surface strengthening method can be introduced first, using either destructive methods (such as blind hole method) or non-destructive methods (such as X-ray diffraction, synchrotron radiation method) to characterize and measure the residual stress of the tested metallic material, and to give the best fitting function equation for the residual stress field, i.e., the optimal residual stress distribution function.

[0046] The residual stress field distribution of the tested metallic material is obtained through residual stress measurement methods (such as the blind hole method, X-ray diffraction, or synchrotron radiation method), and the optimal residual stress σ distribution function relationship is obtained. First, based on the form in which the residual stress is introduced, the obtained residual stress values ​​are substituted into several commonly used residual stress distribution functions for calculation, and the best-fit distribution is selected as the optimal residual stress distribution function:

[0047]

[0048] Formula (1) is applicable to the residual stress field generated by welding and is widely used in the calculation of residual stress distribution near the center weld of a finite width plate. Where σ is the nominal stress, i.e., the residual stress at x = 0; c is the half width of the residual stress zone, where the residual stress is zero at x = c; and C is a constant.

[0049]

[0050] Formula (2) is applicable to the residual stress field generated by surface strengthening, mainly considering the periodic residual stress distribution in an infinitely long plate. It usually takes into account the surface strengthening treatment at the welding or rivet locations of the long plate, where periodic collinear cracks exist in the residual stress field. Wherein, σ is the nominal stress, i.e., the residual stress at x = 0; W is the periodic repeating collinear crack interval of the infinitely long plate or the width of the finite-length plate; the value of n determines the wave number in W, and the optimal residual stress distribution function is obtained by adjusting its value.

[0051] In practical applications, the choice between using formula (1) or formula (2) above can be made based on the initially selected surface treatment method.

[0052] In the specific implementation process, step S10, "determining the optimal residual stress distribution function of the metal material to be tested, and the coefficient values ​​of the optimal residual stress distribution function," can be performed using the following steps:

[0053] Obtain the residual stress introduction method and the actual thickness of the metal material under test;

[0054] Multiple residual stress distribution functions are determined based on the method of introducing residual stress;

[0055] Multiple residual stress distribution functions were tested using residual stress test information that matched the actual thickness.

[0056] Based on the test results, the optimal residual stress distribution function is selected from multiple residual stress distribution functions, and the coefficient values ​​of the optimal residual stress distribution function are determined.

[0057] To facilitate understanding of this invention, the AA2024-T351 alloy is used as an example in the embodiments of this invention:

[0058] First, it is necessary to determine the method of introducing residual stress into the material, which is confirmed to be the deep surface rolling method. Then, based on the actual thickness of the AA2024-T351 alloy, residual stress test information (this residual stress test information is the residual stress test scheme) should be selected. For example, neutron diffraction method can be selected to measure the residual stress in the width and depth directions.

[0059] The optimal residual stress distribution function and its coefficient values ​​are determined from the three residual stress distribution functions shown in Table 1 below. (See also...) Figure 2 , Figure 2This is a schematic diagram of three residual stress distribution curves provided in the embodiments of the present invention. It can represent the comparison of three residual stress distribution functions. The horizontal axis is the width of the plate, the gray rectangular bar is the surface treatment range, and the vertical axis is the residual stress distribution.

[0060] Table 1

[0061]

[0062] The three residual stress distribution functions were tested using the selected residual stress testing scheme. After comparing the test results of the three residual stress distribution functions, cos6πx was selected as the optimal residual stress distribution function, and σ0 = 125 and C = 75 were determined. The function's range of use is -40 to 40.

[0063] S20, based on the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function, calculate the residual stress intensity factor of the metal material to be tested.

[0064] In this embodiment of the invention, after obtaining the optimal residual stress distribution function and its coefficient values, the residual stress intensity factor K of the metal material to be tested can be calculated using the following formula (3). I :

[0065]

[0066] Where a is the initial or pre-set crack length; σ(x) is the optimal residual stress distribution function; K I Let K be the residual stress intensity factor at x. Substituting equations (1) and (2) into equation (3) respectively, the residual stress intensity factor K is calculated by integration. res The following formulas (4) and (5) are respectively:

[0067]

[0068]

[0069] In formula (5) above, J0 is an integer-order Bessel function with a value of 0, which can be calculated using programs such as Matlab. C is a constant.

[0070] To facilitate understanding of this invention, we will continue to use AA2024-T351 alloy as an example for illustration:

[0071] The residual stress intensity factor K is calculated according to the above formula (3). I When the optimal residual stress distribution function cos6πx is determined, it can be substituted into formula (3), and the residual stress intensity factor can be obtained after integration using K. resThis is represented as shown in the following formula (6):

[0072]

[0073] In formula (5) above, J0 is an integer-order Bessel function with a value of 0, which can be calculated using programs such as Matlab.

[0074] S30: Obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the metal material under test.

[0075] In this embodiment of the invention, the crack propagation rate (i.e., the first crack propagation rate) and stress intensity factor range of the base material corresponding to the tested metallic material can be obtained by conducting crack propagation tests. Specifically, crack propagation tests can be performed on the base material or materials without any surface treatment under different stress ratios R to obtain the first crack propagation rate. and stress intensity factor range ΔK app .

[0076] S40, calculate the Walker model constants based on the crack propagation rate and stress intensity factor range, and calculate the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and stress intensity factor range.

[0077] In this embodiment of the invention, after obtaining the first crack propagation rate and stress intensity factor range ΔK app Then, the material constants C0, m, and n in the Walker model can be obtained by substituting them into the following formula (7):

[0078]

[0079] The crack length and number of cycles obtained from the crack propagation test were processed according to the crack propagation treatment method specified in GJB / Z18A to obtain the first crack propagation rate under different stress ratios R. Calculate the corresponding stress intensity factor range ΔK according to the stress intensity factor calculation formula given in the standard or stress intensity factor handbook. app Then, the data under different stress ratios R are fitted according to the above formula (7) to obtain the values ​​of C0, m, and n.

[0080] To facilitate understanding of this invention, we will continue to use AA2024-T351 alloy as an example for illustration:

[0081] Crack propagation tests were conducted on untreated base material (CCT specimens) at different stress ratios R (equal to 0.1, 0.3, and 0.5). The values ​​of C0, m, and n were obtained using the above formula (7), and the stress intensity factor range ΔK was provided. app Specifically:

[0082] The crack length and number of cycles obtained from the crack propagation test are processed according to the crack propagation treatment method specified in GJB / Z18A to obtain the first crack propagation rate. Calculate the corresponding stress intensity factor range ΔK according to the stress intensity factor calculation formula given in the standard or stress intensity factor handbook. app Then, the data under different stress ratio conditions are fitted according to the above formula (7) to obtain C0 = 1 × 10 -7 m = 2.86, n = 0.59.

[0083] In addition, combined with the residual stress intensity factor K res and stress intensity factor range ΔK app The effective stress intensity factor range ΔK can be calculated using the superposition method or the Newman crack closure model. eff And effective stress ratio R eff See formulas (8) and (9) below respectively:

[0084]

[0085] In the above formula (8), σ op The minimum stress for crack opening; σ max R is the maximum stress in the test; R is the stress ratio, determined by K. tot，min / K tot，max It is determined that, in crack propagation tests involving residual stress fields, the stress ratio R needs to be determined by the effective stress ratio R0. eff Replace it.

[0086]

[0087] Where, t′ tot，min =K tot，min +K res , K′ tot，max =K tot，max +K res In the above formula (9), K′ tot，min The range of minimum stress intensity factors containing residual stress fields; K′ tot，max This represents the range of the maximum stress intensity factor containing the residual stress field. For the superposition method, the minimum stress intensity factor range K′ is... tot，min When ≤0, the effective stress ratio R eff=0; For the Newman crack closure model, when the minimum stress intensity factor ranges from K′ tot，min When the effective stress ratio R is ≤0 eff ≤0, calculate the effective stress intensity factor range ΔK eff Use K′ tot，max Instead of ΔK app Continuing with the example of the tested metallic material being AA2024-T351 alloy, see [link to example]. Figure 3 and Figure 4 , Figure 3 This is a schematic diagram illustrating the effect of residual stress on the effective stress intensity factor, provided in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the effect of residual stress on effective specific force in an embodiment of the present invention.

[0088] S50 uses Walker model constants, effective stress intensity factor range, and effective stress ratio to calculate the predicted values ​​of the second crack propagation rate and crack propagation life of the tested metallic material.

[0089] In this embodiment of the invention, the obtained Walker model constant values ​​(C0, m, n values) and effective stress intensity factor range ΔK are used to... eff And effective stress ratio R eff Substituting into the following formula (10) and integrating both sides, we obtain the following formula (11), from which the crack propagation rate (i.e., the second crack propagation rate) of the tested metallic material can be calculated. and crack propagation life N f Predicted values:

[0090]

[0091]

[0092] In the above formula (10), a0 is the initial crack length, a f This represents the crack length at the critical fracture point.

[0093] To facilitate understanding of this invention, we will continue to use AA2024-T351 alloy as the metal material to be tested as an example, with an initial crack length a0 of 4 mm and a crack length at the fracture critical point a f The crack thickness is 30 mm. The second crack propagation rate of the AA2024-T351 alloy can be obtained according to the above formulas (10) and (11). and crack propagation life N f The predicted value. See [reference]. Figure 5 , Figure 5 This is a schematic diagram illustrating the effect of residual stress on crack propagation rate provided in an embodiment of the present invention. Figure 5 The surface strengthening range is 0.01–0.03 μm.

[0094] The fatigue crack propagation life prediction method for metallic materials provided in this invention comprehensively considers the influence of residual stress on the fatigue life of metallic materials, achieving more accurate prediction of fatigue crack propagation life. It considers residual stress introduced by different mechanisms, covering most characteristics of residual stress introduction, and provides a functional expression for the residual stress distribution. Furthermore, this invention considers the influence of specimen form corresponding to different structures and, combined with the Walker model, gives the nonlinear behavior of the crack propagation stage, making it more widely applicable for crack propagation stage analysis and life prediction. It is applicable to aerospace aircraft, aero-engines, and other civilian metallic materials, solving the problem of inaccurate life prediction caused by residual stress introduced after welding or surface treatment.

[0095] Based on the fatigue crack propagation life prediction method for metallic materials provided in the above embodiments, this invention also provides an apparatus for performing the above-described fatigue crack propagation life prediction method for metallic materials, as shown in the schematic diagram below. Figure 6 As shown, it includes:

[0096] The function determination module 10 is used to determine the optimal residual stress distribution function of the metal material under test, as well as the coefficient values ​​of the optimal residual stress distribution function;

[0097] The factor calculation module 20 is used to calculate the residual stress intensity factor of the metal material under test based on the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function.

[0098] The lifetime calculation module 30 is used to obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the metal material under test; calculate the Walker model constant value based on the first crack propagation rate and stress intensity factor range; and calculate the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and stress intensity factor range; and calculate the predicted values ​​of the second crack propagation rate and crack propagation lifetime of the metal material under test using the Walker model constant value, effective stress intensity factor range, and effective stress ratio.

[0099] Optionally, the function determination module 10 is specifically used for:

[0100] Obtain the residual stress introduction method and the actual thickness of the metal material under test; determine multiple residual stress distribution functions based on the residual stress introduction method; test the multiple residual stress distribution functions using residual stress test information that matches the actual thickness; select the optimal residual stress distribution function from the multiple residual stress distribution functions based on the test results, and determine the coefficient value of the optimal residual stress distribution function.

[0101] Optionally, the lifetime calculation module 30, used to obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the tested metallic material, is specifically used for:

[0102] Crack propagation tests were conducted on the parent material corresponding to the tested metallic material under different stress ratios to obtain the first crack propagation rate and stress intensity factor range of the parent material corresponding to the tested metallic material.

[0103] Optionally, a life calculation module 30 is used to calculate the effective stress intensity factor range and effective stress ratio based on the residual stress intensity factor and stress intensity factor range, specifically for:

[0104] By processing the residual stress intensity factor and stress intensity factor range using the superposition method or the Newman crack closure model, the effective stress intensity factor range and effective stress ratio can be obtained.

[0105] It should be noted that the detailed functions of each module in the embodiments of the present invention can be found in the corresponding disclosure of the above-mentioned embodiment of the fatigue crack propagation life prediction method for metallic materials, and will not be repeated here.

[0106] Based on the fatigue crack propagation life prediction method for metallic materials provided in the above embodiments, this invention also provides an electronic device, which includes: at least one memory and at least one processor; the memory stores an application program, and the processor calls the application program stored in the memory, the application program being used to implement the fatigue crack propagation life prediction method for metallic materials.

[0107] Based on the fatigue crack propagation life prediction method for metallic materials provided in the above embodiments, this invention also provides a storage medium storing computer program code, which, when executed, implements the fatigue crack propagation life prediction method for metallic materials.

[0108] The fatigue crack propagation life prediction method, apparatus, and related equipment for metallic materials provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0109] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0110] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that elements inherent to a process, method, article, or apparatus that comprises a list of elements, or elements inherent to such processes, methods, articles, or apparatus, are also included. Without further limitations, 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.

[0111] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of predicting fatigue crack growth life of a metal material, characterized by, The method comprises: determining an optimal residual stress distribution function of a metal material to be tested and a coefficient value of the optimal residual stress distribution function; calculating a residual stress intensity factor of the metal material to be tested according to the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function; obtaining a first crack propagation rate and a stress intensity factor range of a base material corresponding to the metal material to be tested; Walker model constant values are calculated according to the first crack propagation rate and the stress intensity factor range, and effective stress intensity factor range and effective stress ratio are calculated according to the residual stress intensity factor and the stress intensity factor range; wherein, Walker model is a model satisfying a formula , is the first crack propagation rate, is the stress intensity factor range, R is a stress ratio, , m, n are the Walker model constant values; calculating a second crack propagation rate and a prediction value of crack propagation life of the metal material to be tested by using the Walker model constant value, the effective stress intensity factor range and the effective stress ratio.

2. The method of claim 1, wherein, The determination of the optimal residual stress distribution function of the metal material to be tested and the coefficient value of the optimal residual stress distribution function comprises: obtaining a residual stress introduction mode corresponding to the metal material to be tested and an actual thickness of the metal material to be tested; determining a plurality of residual stress distribution functions according to the residual stress introduction mode; testing the plurality of residual stress distribution functions by using residual stress test information matched with the actual thickness; selecting an optimal residual stress distribution function from the plurality of residual stress distribution functions based on a test result and determining a coefficient value of the optimal residual stress distribution function.

3. The method of claim 1, wherein, The obtaining of the first crack propagation rate and the stress intensity factor range of the base material corresponding to the metal material to be tested comprises: performing a crack propagation test on the base material corresponding to the metal material to be tested under different stress ratios to obtain the first crack propagation rate and the stress intensity factor range of the base material corresponding to the metal material to be tested.

4. The method of claim 1, wherein, The calculation of the effective stress intensity factor range and the effective stress ratio according to the residual stress intensity factor and the stress intensity factor range comprises: processing the residual stress intensity factor and the stress intensity factor range by using a superposition method or a Newman crack closure model to obtain the effective stress intensity factor range and the effective stress ratio.

5. A device for predicting the fatigue crack propagation life of metallic materials, characterized in that, The device comprises: a function determination module configured to determine an optimal residual stress distribution function of a metal material to be tested and a coefficient value of the optimal residual stress distribution function; a factor calculation module configured to calculate a residual stress intensity factor of the metal material to be tested according to the optimal residual stress distribution function and the coefficient value of the optimal residual stress distribution function. The life calculation module is configured to obtain a first crack propagation rate and a stress intensity factor range of a base material corresponding to the metal material to be tested; calculate Walker model constant values according to the first crack propagation rate and the stress intensity factor range, wherein the Walker model is a model satisfying a formula , is the first crack propagation rate, is the stress intensity factor range, R is a stress ratio, , m, n are the Walker model constant values, and the effective stress intensity factor range and the effective stress ratio are calculated according to the residual stress intensity factor and the stress intensity factor range; and the Walker model constant values, the effective stress intensity factor range and the effective stress ratio are used to calculate a second crack propagation rate and a prediction value of a crack propagation life of the metal material to be tested.

6. The apparatus of claim 5, wherein, The function determination module is specifically configured to: obtain a residual stress introduction mode corresponding to the metal material to be tested and an actual thickness of the metal material to be tested; determine a plurality of residual stress distribution functions according to the residual stress introduction mode; and test the plurality of residual stress distribution functions by using residual stress test information matched with the actual thickness. select an optimal residual stress distribution function from the plurality of residual stress distribution functions based on a test result and determine a coefficient value of the optimal residual stress distribution function.

7. The apparatus of claim 5, wherein, The life calculation module for obtaining the first crack propagation rate and the stress intensity factor range of the base material corresponding to the metal material to be tested is specifically configured to: The crack propagation test of the base material corresponding to the to-be-tested metal material under different stress ratios is performed to obtain a first crack propagation rate and a stress intensity factor range of the base material corresponding to the to-be-tested metal material.

8. The apparatus of claim 5, wherein, The life calculation module is configured to calculate an effective stress intensity factor range and an effective stress ratio according to the residual stress intensity factor and the stress intensity factor range, and specifically configured to: The residual stress intensity factor and the stress intensity factor range are processed by a superposition method or a Newman crack closure model to obtain the effective stress intensity factor range and the effective stress ratio.

9. An electronic device, comprising: The electronic device includes at least one memory and at least one processor; the memory stores an application program, and the processor invokes the application program stored in the memory; the application program is used to implement the metal material fatigue crack propagation life prediction method in any one of claims 1-4.

10. A storage medium, characterized by The storage medium stores computer program code, and the computer program code is executed to implement the metal material fatigue crack propagation life prediction method in any one of claims 1-4.

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