A Unit Load Method for Predicting the Fatigue Life of Notched Components

Abstract

The present application provides a unit load method for predicting the fatigue life of a notched component, including: applying a unit nominal load to a reference finite element model and a target finite element model respectively to obtain the stress range distribution curves of the reference notched component and the target notched component; for each target failure cycle number, determining the fatigue strength range of the smooth component and the reference notched component at the target failure cycle number; based on the reference fatigue strength range and the reference stress range distribution curve, determining the reference notched root stress range curve; based on the basic fatigue strength range, the reference notched root stress range curve and the target stress range distribution curve, determining the target fatigue strength range of the target notched component at the target failure cycle number, and further predicting the predicted failure cycle number at a specific fatigue strength range. In this way, through linear elastic notch stress analysis with a unit nominal load, the prediction accuracy of the fatigue life of the notched component can be improved and the computational workload can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of fatigue analysis, and particularly to a unit load method for predicting the fatigue life of notched components. Background Art

[0002] In engineering, actual components often have different forms of notches, such as holes, fillets, grooves, shaft shoulders, machining tool marks, and corrosion pits. The stress concentration at the notch weakens the local fatigue resistance of the material, thereby attracting fatigue cracks to nucleate here, so the fatigue failure of mechanical components in engineering practice is mostly related to the notch stress concentration. Due to the stress concentration effect at the notch, the high stress area or crack initiation position of the notched component is usually located at the notch root. Considering the wide application of notched components in engineering practice, studying the fatigue problems of notched components, such as the analysis and prediction of fatigue life, has important theoretical significance and engineering application value.

[0003] Currently, the methods for fatigue analysis of notched components in the prior art are mainly based on the critical distance theory, that is, it is pre-assumed that the critical distance is a power function of the number of failure cycles, and multiple convergent finite element stress analyses are performed on the notched component, especially large-scale mesh refinement is required near the notch root; then fatigue analysis is carried out by iteratively solving the non-linear equations of the stress distribution curve and the critical distance - number of cycles curve. Obviously, the assumption that the critical distance is a power function of the number of failure cycles does not conform to the actual situation of the notched component in many cases, thus bringing analysis errors and affecting the calculation accuracy; in addition, performing multiple finite element stress analyses and iterative solutions of non-linear equations on actual engineering notched components is very time-consuming and laborious, thus affecting the calculation efficiency. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a unit load method for predicting the fatigue life of notched components. By performing linear elastic notch stress analysis with a unit nominal load, it can avoid the prediction error caused by assuming that the critical distance and the number of failure cycles follow a power function relationship, thereby improving the prediction accuracy of the fatigue life of notched components; at the same time, it can avoid iterative operations, thus greatly reducing the computational workload of predicting the fatigue life of notched components.

[0005] The embodiment of the present application provides a unit load method for predicting the fatigue life of notched components, and the method includes:

[0006] Establish a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted;

[0007] Apply a unit nominal load to the reference finite element model and the target finite element model respectively, to obtain the reference stress range distribution curve of the notch root of the reference notch component under the unit nominal load and the target stress range distribution curve of the notch root of the target notch component under the unit nominal load;

[0008] For each of the set multiple target failure cycle numbers, determine the basic fatigue strength range of the smooth component at this target failure cycle number and the reference fatigue strength range of the reference notch component at this target failure cycle number;

[0009] Based on the reference fatigue strength range of the reference notch component at this target failure cycle number and the reference stress range distribution curve, determine the reference notch root stress range curve of the reference notch component under the action of the reference fatigue strength range;

[0010] Based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve, determine the target fatigue strength range of the target notch component at this target failure cycle number;

[0011] Based on the multiple target failure cycle numbers and the target fatigue strength ranges at each target failure cycle number, predict the predicted failure cycle number of the target notch component under a specific fatigue strength range.

[0012] Further, for each of the set multiple target failure cycle numbers, determining the basic fatigue strength range of the smooth component at this target failure cycle number and the reference fatigue strength range of the reference notch component at this target failure cycle number includes:

[0013] Obtain the experimental fatigue strength ranges of the smooth component and the reference notch component at different experimental failure cycle numbers respectively;

[0014] For each target failure cycle number, based on the experimental fatigue strength ranges of the smooth component and the reference notch component at different experimental failure cycle numbers, use numerical interpolation method to determine the basic fatigue strength range of the smooth component at this target failure cycle number and the reference fatigue strength range of the reference notch component at this target failure cycle number.

[0015] Further, for each of the set multiple target failure cycle numbers, determining the basic fatigue strength range of the smooth component at this target failure cycle number and the reference fatigue strength range of the reference notch component at this target failure cycle number further includes:

[0016] Obtain the experimental fatigue strength range of the smooth part and the reference notch part at different experimental failure cycle numbers respectively;

[0017] Based on the experimental fatigue strength ranges of the smooth part and the reference notch part at different experimental failure cycle numbers, fit and calibrate the SN curves in the analytical form of the Basquin equation for the smooth part and the reference notch part;

[0018] Substitute the target failure cycle number into the SN curves in the analytical form of the Basquin equation for the smooth part and the reference notch part respectively, to obtain the basic fatigue strength range of the smooth part at the target failure cycle number and the reference fatigue strength range of the reference notch part at the target failure cycle number.

[0019] Furthermore, based on the reference fatigue strength range of the reference notch part at the target failure cycle number and the reference stress range distribution curve, determine the reference notch root stress range curve of the reference notch part under the action of the reference fatigue strength range through the following formula:

[0020] Δσ r (r) = ΔS r Δσ r_unit (r);

[0021] In the formula, Δσ r (r) represents the reference notch root stress range curve; ΔS r represents the reference fatigue strength range; Δσ r_unit (r) represents the reference stress range distribution curve; r represents the coordinate of any point on the coordinate axis pointing to the reference notch depth direction with the reference notch root on the reference notch part as the origin.

[0022] Furthermore, determining the target fatigue strength range of the target notch part at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve includes:

[0023] Plot the reference notch root stress range curve and the target stress range distribution curve in the same coordinate system;

[0024] Through numerical interpolation method, find the reference point corresponding to the equivalent stress range on the reference notch root stress range curve; the equivalent stress range is equal to the basic fatigue strength range;

[0025] Draw a perpendicular line from the reference point to the horizontal coordinate axis of the coordinate system, and the perpendicular line intersects the target stress range distribution curve at the target point;

[0026] Determine the ordinate value of the target point through a numerical interpolation method;

[0027] Based on the ordinate value of the target point, determine the target fatigue strength range of the target notched component at the target failure cycle number through the following formula:

[0028]

[0029] In the formula, ΔS1 represents the target fatigue strength range; Δσ 1_unit represents the ordinate value of the target point; Δσ eff represents the equivalent stress range; ΔS0 represents the basic fatigue strength range.

[0030] Further, the predicting the predicted failure cycle number of the target notched component at a specific fatigue strength range based on multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number includes:

[0031] Predict the predicted failure cycle number of the target notched component at a specific fatigue strength range through a numerical interpolation method based on multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number; the numerical interpolation method includes a linear interpolation method or a parabolic interpolation method.

[0032] Further, after determining the target fatigue strength range of the target notched component at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, the method further includes:

[0033] Based on the target fatigue strength range and the target stress range distribution curve, determine the target notch root stress range curve of the target notched component under the action of the target fatigue strength range through the following formula:

[0034] Δσ1(r) = ΔS1Δσ 1_unit (r);

[0035] In the formula, Δσ1(r) represents the target notch root stress range curve; ΔS1 represents the target fatigue strength range; Δσ 1_unit (r) represents the target stress range distribution curve; r represents the coordinate of any point on the coordinate axis pointing in the direction of the target notch depth with the target notch root on the target notched component as the origin.

[0036] The embodiment of the present application also provides a unit load device for predicting the fatigue life of a notched component, and the device includes:

[0037] A building module, configured to build a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted;

[0038] A load module, configured to respectively apply a unit nominal load to the reference finite element model and the target finite element model, to obtain a reference stress range distribution curve of the notch root of the reference notched component under the unit nominal load and a target stress range distribution curve of the notch root of the target notched component under the unit nominal load;

[0039] A first determination module, configured to determine, for each of a plurality of set target failure cycle numbers, a basic fatigue strength range of a smooth component under the target failure cycle number and a reference fatigue strength range of the reference notched component under the target failure cycle number;

[0040] A second determination module, configured to determine a reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range based on the reference fatigue strength range of the reference notched component under the target failure cycle number and the reference stress range distribution curve;

[0041] A third determination module, configured to determine a target fatigue strength range of the target notched component under the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve;

[0042] A prediction module, configured to predict a predicted failure cycle number of the target notched component under a specific fatigue strength range based on the plurality of target failure cycle numbers and the target fatigue strength range under each target failure cycle number.

[0043] An embodiment of the present application further provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device runs, the processor communicates with the memory through the bus. When the machine-readable instructions are executed by the processor, the steps of a unit load method for predicting the fatigue life of a notched component as described above are executed.

[0044] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, the steps of a unit load method for predicting the fatigue life of a notched component as described above are executed.

[0045] A unit load method for predicting the fatigue life of a notched component provided by an embodiment of the present application includes: establishing a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted; applying a unit nominal load to the reference finite element model and the target finite element model respectively to obtain a reference stress range distribution curve of the notch root of the reference notched component under the unit nominal load and a target stress range distribution curve of the notch root of the target notched component under the unit nominal load; for each of a set of multiple target failure cycle numbers, determining the basic fatigue strength range of a smooth component at the target failure cycle number and the reference fatigue strength range of the reference notched component at the target failure cycle number; based on the reference fatigue strength range of the reference notched component at the target failure cycle number and the reference stress range distribution curve, determining a reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range; based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve, determining the target fatigue strength range of the target notched component at the target failure cycle number; based on the multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number, predicting the predicted failure cycle number of the target notched component at a specific fatigue strength range.

[0046] Compared with the fatigue analysis method in the prior art, linear elastic notch stress analysis by unit nominal load can avoid the prediction error caused by assuming that the critical distance and the failure cycle number follow a power function relationship, thereby improving the prediction accuracy of the fatigue life of the notched component; at the same time, it can avoid iterative operations, thereby greatly reducing the computational workload of predicting the fatigue life of the notched component.

[0047] To make the above objects, features and advantages of the present application more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, makes the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1 Shows a flowchart of a unit load method for predicting the fatigue life of a notched component provided by an embodiment of the present application;

[0050] Figure 2The figure shows a schematic diagram of the unit load method for predicting the fatigue life of a notched component provided by an embodiment of the present application;

[0051] Figures 3(a) and (b) show schematic diagrams of the experimental results of a comparative experiment provided by an embodiment of the present application;

[0052] Figure 4 The figure shows a schematic structural diagram of a unit load device for predicting the fatigue life of a notched component provided by an embodiment of the present application;

[0053] Figure 5 The figure shows a schematic structural diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and illustrated herein generally may be arranged and designed in a variety of different configurations. Therefore, the detailed description of the embodiments of the present application provided herein is not intended to limit the scope of the claimed present application, but is merely representative of selected embodiments of the present application. Based on the embodiments of the present application, every other embodiment obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0055] Through research, it is found that in engineering, actual components often have different forms of notches, such as holes, fillets, grooves, shaft shoulders, machining tool marks, and corrosion pits. The stress concentration at the notch will weaken the local fatigue resistance of the material, thus attracting fatigue cracks to nucleate from here, so the fatigue failure of mechanical components in engineering practice is mostly related to the notch stress concentration. Due to the stress concentration effect at the notch, the high stress area or crack initiation position of the notched component is usually located at the notch root. Considering the wide application of notched components in engineering practice, studying the fatigue problems of notched components, such as the analysis and prediction of fatigue life, has important theoretical significance and engineering application value.

[0056] Currently, the methods for fatigue analysis of notched components in the prior art are mainly based on the critical distance theory (MCF-TCD method), and its basic assumption is: If the number of failure cycles of a notched component under the fatigue load ΔS n (nominal stress range) is N, and the fatigue strength (range) of a smooth component under the same number of failure cycles N is ΔS, then the notched component under ΔS n acts at a distance r from the root surface at the notch root cThe principal stress range at / 2 (i.e., the equivalent stress range Δσ in the TCD method) eff ) should be equal to ΔS, where r c is called the "critical distance". In the "line method" of TCD, Δσ eff is the average value of the principal stress at the notch root from the notch root surface to 2r c .

[0057] From the above description of the basic principle of the MCF-TCD method, it can be seen that the key to predicting the fatigue life / strength of notched components using the MCF-TCD method is to determine the critical distance r c . Therefore, the MCF-TCD method presupposes that the critical distance is a power function of the number of failure cycles. Then, multiple convergent finite element stress analyses are performed on the notched component, especially with significant mesh refinement near the notch root; and then fatigue analysis is carried out by iteratively solving the nonlinear equations of the stress distribution curve and the critical distance - number of cycles curve.

[0058] Obviously, the assumption that the critical distance is a power function of the target number of failure cycles does not conform to the actual situation of the notch in many cases, thus bringing analysis errors and affecting the calculation accuracy; in addition, from the calibration of the power function between the critical distance and the target number of failure cycles to the iterative solution of the nonlinear equation, multiple finite element stress analyses of the notched component are required; and to obtain the principal stress distribution function Δσ eff (r) of the notch root, the mesh needs to be refined and a convergent finite element solution needs to be obtained, which is very time-consuming and laborious, especially for solving the notch problems of engineering actual components. In addition, generally, the analytical expression of the principal stress distribution function Δσ eff (r) is obtained by data regression of the finite element stress analysis results, which often brings errors because there is generally no unified analytical expression for the stress distribution at the notch root of the notched component, especially for engineering components. In summary, there are deficiencies in both the calculation efficiency and prediction accuracy in the prior art when performing fatigue analysis of notched components.

[0059] Based on this, the embodiments of the present application provide a unit load method for predicting the fatigue life of notched components, which can perform linear elastic notch stress analysis through a unit nominal load, avoid the prediction errors caused by assuming the power function relationship between the critical distance and the number of failure cycles, thereby improving the prediction accuracy of the fatigue life of notched components; and at the same time can avoid iterative operations, thus greatly reducing the calculation workload for predicting the fatigue life of notched components.

[0060] Please refer to Figure 1 and Figure 2 , Figure 1 which is a flowchart of a unit load method for predicting the fatigue life of notched components provided by the embodiments of the present application; Figure 2Schematic diagram of a unit load method for predicting the fatigue life of a notched component provided by an embodiment of the present application. As Figure 1 shown in

[0061] S101. Establish a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted.

[0062] Among them, the reference notched component and the target notched component are made of the same material. In specific implementation, the reference finite element model of the reference notched component and the target finite element model of the target notched component can be established based on any method in the prior art, and the present application does not limit this here.

[0063] S102. Apply a unit nominal load to the reference finite element model and the target finite element model respectively to obtain a reference stress range distribution curve at the notch root of the reference notched component under the unit nominal load and a target stress range distribution curve at the notch root of the target notched component under the unit nominal load.

[0064] Among them, the nominal load is the working load applied to the part by the machine under quasi-static conditions. The unit refers to the name of the standard quantity for measuring things in the mathematical or physical aspect. Defining a certain quantity of a substance as "1" becomes a unit. In different embodiments, the unit can be 1 Newton or 1 kilogram, etc. The stress analyst should keep the unit system unified by himself. In the present invention, the above unit nominal load "1" is the unit nominal load range applied to the reference finite element model and the target finite element model of the part.

[0065] Here, the reference stress range distribution curve Δσ r_unit (r) is used to describe the distribution of the stress range of the reference notched component at its notch root along the depth under the unit nominal load; the target stress range distribution curve Δσ 1_unit (r) is used to describe the distribution of the stress range of the target notched component at its notch root along the depth under the unit nominal load; by using the linear elastic finite element method (a widely used numerical method for solving partial differential equations), the reference stress range distribution curve and the target stress range distribution curve can be obtained.

[0066] The above stress range is the standard definition in fatigue and fracture theory, which refers to the difference between the maximum stress and the minimum stress generated at a certain point on the part under one fatigue load cycle. For example, under a sinusoidal fatigue load, the stress range at a certain point is twice the sinusoidal stress amplitude generated at that point.

[0067] The above stress range distribution curve refers to the distribution curve of the stress range along the depth direction of the notch root.

[0068] By applying a unit nominal load to the reference notched component, a reference finite element model can be established, and through finite element analysis, the reference stress range distribution curve Δσ r_unit (r) can be obtained; by applying a unit nominal load to the target notched component, a target finite element model can be established, and through finite element analysis, the target stress range distribution curve Δσ r_unit (r) can be obtained.

[0069] As Figure 2 shown, Figure 2 in the left coordinate system in r_unit , the reference stress range distribution curve Δσ 1_unit (r) at the notch root of the reference notched component under the unit nominal load and the target stress range distribution curve Δσ

[0070] (r) at the notch root of the target notched component under the unit nominal load are plotted. Figure 2 It should be noted that the continuous forms of the reference stress range distribution curve and the target stress range distribution curve plotted in

[0071] are only for the convenience of explanation. In fact, the reference stress range distribution curve and the target stress range distribution curve may not be continuous curve forms, but a set of multiple discrete points stored in an array form. An element in the array represents the coordinates of a discrete point. Through fitting and calibration of the coordinates of multiple discrete points, a continuous curve of the continuous stress range distribution can be obtained; in addition, in subsequent steps, numerical interpolation calculations can also be performed based on the coordinates of multiple discrete points to obtain the coordinates of any point that should be located on the stress range distribution curve. Therefore, to ensure the interpolation accuracy, the set of multiple discrete points stored in an array form should have a sufficiently small interpolation interval.

[0072] In this step, for each target failure cycle number N among the set of multiple target failure cycle numbers N1, N2, N3, …, N n under the condition that 1 ≤ i ≤ n, where both i and n are positive integers, the basic fatigue strength range of the smooth component and the reference fatigue strength range of the reference notched component at this target failure cycle number N i can be determined in the following manner: i i r r r :

[0073] S1031: Obtain the experimental fatigue strength ranges of the smooth component and the reference notched component at different experimental failure cycle numbers respectively.

[0074] In this step, the smooth part is a workpiece without a notch and is made of the same material as the reference notched part and the target notched part. The experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers can be obtained in advance through experiments respectively.

[0075] S1032. For each target failure cycle number, based on the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers, the numerical interpolation method is used to determine the basic fatigue strength range of the smooth part at this target failure cycle number and the basic fatigue strength range of the reference notched part at this target failure cycle number.

[0076] In this step, because the target failure cycle number N i is not necessarily equal to the experimental failure cycle number set in the experiment, that is, the target failure cycle number N i corresponding basic fatigue strength range ΔS0 and reference fatigue strength range ΔS r cannot be directly obtained through pre-experiments. Therefore, based on the different experimental failure cycle numbers of the smooth part and the reference notched part and the experimental fatigue strength ranges at each experimental failure cycle number, the numerical interpolation method can be used to respectively determine the basic fatigue strength range ΔS0 of the smooth part at this target failure cycle number N i and the reference fatigue strength range ΔS of the reference notched part at this target failure cycle number N i . Among them, the numerical interpolation method can be any data interpolation calculation method in the prior art. For example, the linear interpolation method and the parabolic interpolation method, etc. r .

[0077] In another possible implementation manner, step S103 may further include:

[0078] S1031. Obtain the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers respectively.

[0079] S1033. Based on the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers, fit and calibrate to obtain the SN curve in the form of the Basquan equation analytical formula of the smooth part and the reference notched part.

[0080] In this step, it can be assumed that the SN curves of the materials of the smooth part and the reference notch part satisfy the Basquin equation (a straight line in a double logarithmic coordinate system). The experimental fatigue strength ranges of the smooth part and the reference notch part obtained through experiments at different experimental failure cycle numbers are used to fit and calibrate the original Basquin equation analytical formula respectively, so as to obtain the Basquin equation analytical formula form of the SN curve of the smooth part and the Basquin equation analytical formula form of the SN curve of the reference notch part. Among them, the SN curve takes the fatigue strength of the workpiece as the ordinate and the fatigue life or the logarithm of the fatigue life as the abscissa, which is used to represent the relationship between the fatigue strength and the fatigue life of the workpiece under a certain cyclic characteristic, and is also called the stress-life curve.

[0081] S1034. Substitute the target failure cycle number into the SN curves in the form of the Basquin equation analytical formula of the smooth part and the reference notch part respectively, to obtain the basic fatigue strength range of the smooth part at the target failure cycle number and the reference fatigue strength range of the reference notch part at the target failure cycle number.

[0082] In this step, after obtaining the SN curves in the form of the Basquin equation analytical formula of the smooth part and the reference notch part respectively, the target failure cycle number can be substituted into the Basquin equation analytical formula respectively to calculate the basic fatigue strength range ΔS0 of the smooth part at the target failure cycle number N i and the reference fatigue strength range ΔS i of the reference notch part at the target failure cycle number N r .

[0083] Similarly, as Figure 2 shown, Figure 2 in the right coordinate system in, the SN curve of the reference notch part and the SN curve of the smooth part are plotted. The prediction target of this application is to predict the predicted failure cycle number of the target notch part under a specific fatigue strength range by determining the target fatigue strength range ΔS1 of the target notch part at different target failure cycle numbers N i . And through the target fatigue strength range ΔS1 of the target notch part at different target failure cycle numbers N i , the SN curve of the target notch part shown in Figure 2 can be fitted and calibrated.

[0084] It should also be noted that Figure 2The continuous forms of the SN curves of the reference notched component and the smooth component plotted are only for illustrative purposes. In fact, the SN curves of the reference notched component and the smooth component may not be continuous curve forms, but a set of multiple discrete points stored in an array form, and one element in the array represents the coordinates of a discrete point. By performing fitting calibration through the coordinates of multiple discrete points, a continuous SN curve can be obtained; in addition, in subsequent steps, numerical interpolation calculations can also be performed through the coordinates of multiple discrete points to obtain the coordinates of any point that should be located on the SN curve. At this time, to ensure the interpolation accuracy, the set of multiple discrete points stored in the array form should have a sufficiently small interpolation interval.

[0085] S104. Based on the reference fatigue strength range at the target failure cycle number of the reference notched component and the reference stress range distribution curve, determine the reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range.

[0086] In a possible implementation manner, based on linear theory, in step S104, the reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range ΔS r can be determined by the following formula:

[0087] Δσ r (r) = ΔS r Δσ r_unit (r);

[0088] In the formula, Δσ r (r) represents the reference notch root stress range curve; ΔS r represents the reference fatigue strength range; Δσ r_unit (r) represents the reference stress range distribution curve; r represents the coordinate of any point on the coordinate axis pointing in the reference notch depth direction with the reference notch root on the reference notched component as the origin (see the r-axis in Figure 2 ).

[0089] Here, the reference notch root stress range curve Δσ r (r) is used to describe the stress range distribution along the depth of the reference notch root under the action of the reference fatigue strength range ΔS r .

[0090] As shown in Figure 2 , Figure 2 the reference notch root stress range curve Δσ r (r) and the reference stress range distribution curve Δσ r_unit (r) are plotted in the same coordinate system on the left in

[0091] S105. Based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, determine the target fatigue strength range of the target notch component at the target failure cycle number.

[0092] In a possible implementation, step S105 may include:

[0093] S1051. Plot the reference notch root stress range curve and the target stress range distribution curve in the same coordinate system.

[0094] S1052. By means of numerical interpolation, find the reference point corresponding to the equivalent stress range on the reference notch root stress range curve; the equivalent stress range is equal to the basic fatigue strength range.

[0095] S1053. Draw a perpendicular line from the reference point perpendicular to the horizontal axis of the coordinate system, and the perpendicular line intersects the target stress range distribution curve at a target point.

[0096] S1054. By means of numerical interpolation, determine the ordinate value of the target point.

[0097] S1055. Based on the ordinate value of the target point, determine the target fatigue strength range of the target notch component at the target failure cycle number through the following formula:

[0098]

[0099] In the formula, ΔS1 represents the target fatigue strength range; Δσ 1_unit represents the ordinate value of the target point; Δσ eff represents the equivalent stress range; ΔS0 represents the basic fatigue strength range.

[0100] Next, a calculation example of determining the target fatigue strength range ΔS1 of the target notch component at the target failure cycle number N Figure 2 will be given. i The following is a calculation example of determining the target fatigue strength range ΔS1 of the target notch component at the target failure cycle number N

[0101] As Figure 2 shown, first, plot the reference notch root stress range curve Δσ r (r) and the target stress range distribution curve Δσ 1_unit (r) in the same coordinate system on the left side in Figure 2 .

[0102] Secondly, by means of numerical interpolation, find the equivalent stress range Δσ r equal to the basic fatigue strength range ΔS0 on the reference notch root stress range curve Δσ effAnd the equivalent stress range Δσ eff The corresponding r, i.e., the equivalent stress range Δσ eff The corresponding reference point. According to the basic assumption of the critical distance theory: when the number of failure cycles is the same, the principal stress range (equivalent stress) at a distance of r c / 2 from the root surface of the notched component to the root is equal to the fatigue strength (range) of the smooth component; then the equivalent stress range Δσ eff The corresponding r is equal to r c / 2, where r c Represents the critical distance corresponding to the target number of failure cycles N i . Corresponding to Figure 2 , in specific implementation, a straight line Δσ = ΔS0 = Δσ Figure 2 Parallel to the horizontal axis can be drawn in the left coordinate system of eff . The straight line intersects the reference notch root stress range curve Δσ r (r) at point P e . Then point P e Is the reference point, and its coordinates are (r c / 2, Δσ eff ).

[0103] Again, through the numerical interpolation method, the target stress range Δσ 1_unit Of the target notched component corresponding to r c / 2 can be found on the target stress range distribution curve Δσ 1_unit . Corresponding to Figure 2 , in specific implementation, in Figure 2 , a perpendicular line to the horizontal axis of the coordinate system can be drawn through the reference point P e . The perpendicular line intersects the target stress range distribution curve Δσ 1_unit (r) at point P1, and point P1 is the target point; through the numerical interpolation method, the ordinate value of the target point P1 can be determined to be Δσ 1_unit , that is, the coordinates of the target point P1 are (r c / 2, Δσ 1_unit ).

[0104] Finally, the target fatigue strength range ΔS1 of the target notched component at the target number of failure cycles N i Can be determined by the following formula:

[0105]

[0106] In the formula, ΔS1 represents the target fatigue strength range; Δσ 1_unit Represents the ordinate value of the target point; Δσ eff Represents the equivalent stress range; ΔS0 represents the basic fatigue strength range.

[0107] S106. Predict the predicted failure cycle times of the target notched component at a specific fatigue strength range based on the multiple target failure cycle times and the target fatigue strength ranges at each target failure cycle time.

[0108] Among them, the specific fatigue strength range can be set according to research needs; in specific implementation, as Figure 2 shown, after obtaining the target fatigue strength range ΔS1 at the target failure cycle time N i through the foregoing method, the point (N i , ΔS1) can be marked in the right coordinate system in Figure 2 ; by continuously changing the target failure cycle time N i , the same method can be used to obtain the target fatigue strength ranges corresponding to different target failure cycle times N1, N2, N3,..., N n .

[0109] After that, based on the multiple target failure cycle times and the target fatigue strength ranges at each target failure cycle time, the continuous SN curve and the analytical formula of the SN curve of the target notched component can be obtained through fitting and calibration. Then, substituting the specific fatigue strength range ΔS j into the analytical formula, the predicted failure cycle time N j of the target notched component at the specific fatigue strength range ΔS j can be calculated, that is, the predicted fatigue life of the target notched component at the specific fatigue strength range ΔS j . In specific implementation, it is equivalent to making a straight line parallel to the horizontal axis, ΔS = ΔS j , and the straight line intersects the SN curve of the target notched component at the prediction point P j , and find the abscissa of the prediction point P j .

[0110] Similarly, based on the multiple target failure cycle times N i and the target fatigue strength ranges ΔS1 at each target failure cycle time, the predicted failure cycle time N j of the target notched component at the specific fatigue strength range ΔS1 can also be predicted through numerical interpolation method, that is, the predicted fatigue life of the target notched component at the specific fatigue strength range ΔS j ; the numerical interpolation method includes linear interpolation method or parabolic interpolation method.

[0111] Furthermore, after determining the target fatigue strength range of the target notched component at the target failure cycle time in step S105 based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, the method further includes:

[0112] S107. Based on the target fatigue strength range and the target stress range distribution curve, determine the target notch root stress range curve of the target notch component under the action of the target fatigue strength range through the following formula:

[0113] Δσ1(r) = ΔS1Δσ 1_unit (r);

[0114] In the formula, Δσ1(r) represents the target notch root stress range curve; ΔS1 represents the target fatigue strength range; Δσ 1_unit (r) represents the target stress range distribution curve; r represents the coordinate of any point on the coordinate axis pointing in the direction of the target notch depth with the target notch root on the target notch component as the origin (see the r-axis in Figure 2 ). It should be noted that for the convenience of description, in the embodiments of the present application Figure 2 the target notch root coordinate system and the reference notch root coordinate system are the same coordinate system, but in actual applications, the target notch root coordinate system and the reference notch root coordinate system are not limited to the same coordinate system.

[0115] Here, the target notch root stress range curve Δσ1(r) is used to describe the stress range distribution along the depth of the target notch root under the action of the target fatigue strength range ΔS1.

[0116] Similarly, Figure 2 shows the target notch root stress range curve Δσ1(r) and the target stress range distribution curve Δσ in the same coordinate system 1_unit (r), and the target notch root stress range curve Δσ1(r) also passes through the reference point P e .

[0117] In the above algorithm, the finite element method is adopted for the stress distribution at the notch root. To ensure the prediction accuracy, the convergent finite element stress analysis results should be adopted. For the S-N curves of smooth components and reference notch components, if there is no analytical expression such as the Basquan equation, the discrete points of the median S-N curve obtained by experiments can also be used for interpolation calculation.

[0118] At the same time, it should be noted that the notch component with a sharp notch should be selected as the reference notch component as much as possible, that is, the first derivative Δσ′ of the principal stress at the notch root of the reference notch component 1_unit(r) The value at r should be greater than a preset threshold or the stress gradient at the notch root of the reference notch component should be greater than a preset threshold. This is because: The critical distance method belongs to a "local" method, that is, it studies the fatigue behavior in a small area at the notch root of the fatigue process zone. For a "blunt" notch, the stress gradient at its notch root is very small, and its fatigue behavior is closer to that of a smooth component without a notch. Or rather, compared with a "sharp" notch component, its fatigue notch effect is not obvious, and its fatigue behavior is relatively not "local". Therefore, using it as a reference notch component to predict the fatigue behavior of a "sharp" notch component will bring relatively large errors. On the contrary, using a notch component with a sharp notch as a reference notch component to predict a blunt notch, because the stress gradient of the blunt notch component is small, the prediction error caused by the inaccuracy of the critical distance prediction is not large. That is to say, using a "blunt" notch as a reference notch to predict the fatigue behavior of a "sharp" notch will lead to an increase in the prediction error, and vice versa, the prediction error will decrease.

[0119] In an experiment, the MCF-TCD method of Susmel and Taylor and the method provided in this application were respectively used to analyze and predict the notch component fatigue S-N curve of the axial tensile fatigue test results of a central circular hole plate specimen of 7075-T6 aluminum alloy in the Langley Aeronautical Laboratory. The schematic diagrams of the experimental results of the comparative experiment are shown in Figs. 3(a) and (b), where the axial tensile fatigue S-N curve of the 7075-T6 aluminum alloy smooth specimen used is from another report of the Langley Aeronautical Laboratory. The ultimate tensile strength of the material is 527.3 MPa, and the yield limit is 520.6 MPa. The thickness of the plate is 2.286 mm (0.09 inches), the width of the maximum stress section of the smooth component is 25.4 mm (1 inch), and the specimen numbers and parameters are shown in Table 1 (No. 0 is the smooth component without a notch). Where d is the diameter of the circular hole, W is the width of the specimen, L is the length of the specimen, K t and K g are the finite element calculation results of the elastic static stress concentration factor and the total stress concentration factor respectively. The test stress ratio R = 0. In the finite element stress analysis, the element line scale at the notch root is between 0.002 and 0.008 mm. The element used is the 4-node quadrilateral linear element PLANE42 of ANSYS. The symmetry of the model and the load was considered in the modeling, and the total number of equations is about 1 million. ANSYS is a large general-purpose finite element analysis software developed by ANSYS, Inc. in the United States.

[0120] Table 1 Specimen geometric dimension parameters and stress concentration factors

[0121]

[0122] In this experiment, the experimental S-N curve of the specimen is shown in Fig. 3(a) (about between 10 4 ~10 6Between cyclic periods, the vertical axis has been converted from the net stress in the original literature to the total stress range Δσ gross (Far - field stress range); The least - squares linear regression parameters of the S - N curve are shown in Table 2 below; Using the embodiment of the present application to predict its notch - root critical distance - cycle number curve (R - N curve) is shown in Figure 3(b).

[0123] Table 2 Least - squares linear regression parameter table of the experimental S - N curve

[0124]

[0125] The experimental results show that the relationship between the critical distance and the cycle number does not satisfy the power - function relationship, but is closer to the logarithmic - function relationship. Moreover, the critical - distance curves of the notched specimens of the three types do not coincide. In particular, the critical - distance curve of the notched specimen No.3 is quite different from those of the other two notched specimens, indicating that the critical distance is not only related to the material and the failure cycle number, but also related to the notch geometry. Since the geometric dimensions of the notches of No.1 and No.2 are similar and the stress - concentration coefficients are also close, their R - N curves are relatively close, but there are also significant differences when approaching the 6 failure cycle number.

[0126] Furthermore, the experimental results show that the relative errors of fatigue prediction for the notched specimens of the three types using the two methods are both less than 20% (within 2×10 3 ~2×10 6 cycle numbers). However, the average relative standard deviation of prediction using the present method is significantly smaller. For the notched specimens No.1 and No.2, the relative error of prediction using the present method is within 5%. While the MCF - TCD algorithm has relatively large relative errors when less than 10 4 or greater than 10 6 cycle numbers. The main reason for this situation is that the relationship between the critical distance and the cycle number does not satisfy the power - function relationship. Specifically, the average relative standard deviation S dev of the prediction results of the two methods is shown in Table 3:[[]]END]]

[0127] Table 3 Average relative standard deviation of the prediction results of the two algorithms

[0128]

[0129] A unit load method for predicting the fatigue life of a notched component provided by an embodiment of the present application includes: establishing a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted; applying a unit nominal load to the reference finite element model and the target finite element model respectively to obtain a reference stress range distribution curve of the notch root of the reference notched component under the unit nominal load and a target stress range distribution curve of the notch root of the target notched component under the unit nominal load; for each of a plurality of set target failure cycle numbers, determining the basic fatigue strength range of a smooth component at the target failure cycle number and the reference fatigue strength range of the reference notched component at the target failure cycle number; based on the reference fatigue strength range of the reference notched component at the target failure cycle number and the reference stress range distribution curve, determining a reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range; based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve, determining the target fatigue strength range of the target notched component at the target failure cycle number; and predicting the predicted failure cycle number of the target notched component at a specific fatigue strength range based on the plurality of target failure cycle numbers and the target fatigue strength range at each target failure cycle number.

[0130] Compared with the fatigue analysis methods in the prior art, the method provided by the embodiment of the present application has the following advantages:

[0131] (1) This method does not require an explicit critical distance - failure cycle number function, that is, it does not assume that the critical distance and the failure cycle number follow a power function relationship, thus avoiding the prediction error caused by the inconsistency between this assumption and the actual workpiece situation, and improving the prediction accuracy of the fatigue life of the notched component.

[0132] (2) This method only needs to perform a convergent unit load finite element stress analysis on the reference notched component and the target notched component once each, and only uses interpolation to solve instead of iterative solution, greatly reducing the computational workload and thus improving the computational efficiency.

[0133] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of a unit load device for predicting the fatigue life of a notched component provided by an embodiment of the present application. As shown in Figure 4 , the device 300 includes:

[0134] A building module 310, configured to establish a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted;

[0135] A load module 320, configured to apply a unit nominal load to the reference finite element model and the target finite element model respectively, so as to obtain a reference stress range distribution curve of the notch root of the reference notch component under the unit nominal load and a target stress range distribution curve of the notch root of the target notch component under the unit nominal load;

[0136] A first determination module 330, configured to determine, for each of a set of multiple target failure cycle numbers, the basic fatigue strength range of the smooth component at the target failure cycle number and the reference fatigue strength range of the reference notch component at the target failure cycle number;

[0137] A second determination module 340, configured to determine a reference notch root stress range curve of the reference notch component under the action of the reference fatigue strength range based on the reference fatigue strength range of the reference notch component at the target failure cycle number and the reference stress range distribution curve;

[0138] A third determination module 350, configured to determine the target fatigue strength range of the target notch component at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve;

[0139] A prediction module 360, configured to predict the predicted failure cycle number of the target notch component under a specific fatigue strength range based on the set of multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number.

[0140] Further, when the first determination module 330 is configured to determine, for each of a set of multiple target failure cycle numbers, the basic fatigue strength range of the smooth component at the target failure cycle number and the reference fatigue strength range of the reference notch component at the target failure cycle number, the first determination module 330 is configured to:

[0141] Obtain the experimental fatigue strength ranges of the smooth component and the reference notch component at different experimental failure cycle numbers respectively;

[0142] For each target failure cycle number, based on the experimental fatigue strength ranges of the smooth component and the reference notch component at different experimental failure cycle numbers, use numerical interpolation to determine the basic fatigue strength range of the smooth component at the target failure cycle number and the reference fatigue strength range of the reference notch component at the target failure cycle number.

[0143] Further, when the first determination module 330 is used to determine the basic fatigue strength range of the smooth part and the reference fatigue strength range of the reference notched part at each of a set of target failure cycle numbers, the first determination module 330 is further used for:

[0144] Obtain the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers respectively;

[0145] Based on the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers, fit and calibrate to obtain the SN curves in the analytical form of the Basquin equation for the smooth part and the reference notched part;

[0146] Substitute the target failure cycle number into the SN curves in the analytical form of the Basquin equation for the smooth part and the reference notched part respectively to obtain the basic fatigue strength range of the smooth part and the reference fatigue strength range of the reference notched part at the target failure cycle number.

[0147] Further, the second determination module 340 determines the reference notch root stress range curve of the reference notched part under the action of the reference fatigue strength range based on the reference fatigue strength range of the reference notched part at the target failure cycle number and the reference stress range distribution curve through the following formula:

[0148] Δσ r (r) = ΔS r Δσ r_unit (r);

[0149] In the formula, Δσ r (r) represents the reference notch root stress range curve; ΔS r represents the reference fatigue strength range; Δσ r_unit (r) represents the reference stress range distribution curve; r represents the coordinate of any point on the coordinate axis pointing in the direction of the reference notch depth with the reference notch root on the reference notched part as the origin.

[0150] Further, when the third determination module 350 is used to determine the target fatigue strength range of the target notched part at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, the third determination module 350 is used for:

[0151] Plot the reference notch root stress range curve and the target stress range distribution curve in the same coordinate system;

[0152] By means of a numerical interpolation method, find a reference point corresponding to the equivalent stress range on the reference notch root stress range curve; the equivalent stress range is equal to the basic fatigue strength range.

[0153] Draw a perpendicular line through the reference point perpendicular to the horizontal axis of the coordinate system, and the perpendicular line intersects the target stress range distribution curve at a target point.

[0154] Determine the ordinate value of the target point by means of a numerical interpolation method.

[0155] Based on the ordinate value of the target point, determine the target fatigue strength range of the target notch component at the target failure cycle number through the following formula:

[0156]

[0157] In the formula, ΔS1 represents the target fatigue strength range; Δσ 1_unit represents the ordinate value of the target point; Δσ eff represents the equivalent stress range; ΔS0 represents the basic fatigue strength range.

[0158] When the prediction module 360 is used to predict the predicted failure cycle number of the target notch component at a specific fatigue strength range based on multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number, the prediction module 360 is used for:

[0159] Based on multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number, predict the predicted failure cycle number of the target notch component at a specific fatigue strength range through a numerical interpolation method; the numerical interpolation method includes a linear interpolation method or a parabolic interpolation method.

[0160] Furthermore, the device 300 further includes a fourth determination module; the fourth determination module is used for:

[0161] Based on the target fatigue strength range and the target stress range distribution curve, determine the target notch root stress range curve of the target notch component under the action of the target fatigue strength range through the following formula:

[0162] Δσ1(r) = ΔS1Δσ 1_unit (r);

[0163] In the formula, Δσ1(r) represents the target notch root stress range curve; ΔS1 represents the target fatigue strength range; Δσ 1_unit(r) represents the target stress-strain range distribution curve; r represents the coordinate of any point on the coordinate axis pointing in the direction of the target notch depth with the root of the target notch on the target notch component as the origin.

[0164] Please refer to Figure 5 , Figure 5 , which is a schematic structural diagram of an electronic device provided by an embodiment of the present application. As Figure 5 shown in, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.

[0165] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 runs, the processor 410 communicates with the memory 420 through the bus 430. When the machine-readable instructions are executed by the processor 410, the steps of a unit load method for predicting the fatigue life of a notch component as described above Figure 1 to the method embodiment shown in FIG. 3 can be executed. The specific implementation manner can refer to the method embodiment and will not be elaborated here.

[0166] The embodiment of the present application further provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is run by a processor, the steps of a unit load method for predicting the fatigue life of a notch component as described above Figure 1 to the method embodiment shown in FIG. 3 can be executed. The specific implementation manner can refer to the method embodiment and will not be elaborated here.

[0167] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0168] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the couplings, direct couplings, or communication connections shown or discussed with each other can be through some communication interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0169] The unit described as a separation component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0170] In addition, in each embodiment of the present application, each functional unit may be integrated in a processing unit, may exist separately as individual physical units, or two or more units may be integrated in one unit.

[0171] If the described function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store program codes.

[0172] Finally, it should be noted that the above-described embodiments are only specific implementation manners of the present application, used to illustrate the technical solutions of the present application, and are not intended to limit it. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed in the present application can still modify the technical solutions described in the foregoing embodiments or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes, or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application and should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A unit load method for predicting the fatigue life of a notched component, characterized in that, The method includes: establishing a reference finite element model of a reference notched component and a target finite element model of a target notched component to be predicted; applying a unit nominal load to the reference finite element model and the target finite element model respectively to obtain a reference stress range distribution curve of the notch root of the reference notched component under the unit nominal load and a target stress range distribution curve of the notch root of the target notched component under the unit nominal load; for each of a plurality of set target failure cycle numbers, determining a basic fatigue strength range of a smooth component at the target failure cycle number and a reference fatigue strength range of the reference notched component at the target failure cycle number; based on the reference fatigue strength range of the reference notched component at the target failure cycle number and the reference stress range distribution curve, determining a reference notch root stress range curve of the reference notched component under the action of the reference fatigue strength range; based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve, determining the target fatigue strength range of the target notched component at the target failure cycle number; predicting a predicted failure cycle number of the target notched component at a specific fatigue strength range based on the plurality of target failure cycle numbers and the target fatigue strength ranges at each target failure cycle number; The determining the target fatigue strength range of the target notched component at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve and the target stress range distribution curve includes: plotting the reference notch root stress range curve and the target stress range distribution curve in the same coordinate system; finding a reference point corresponding to an equivalent stress range on the reference notch root stress range curve by a numerical interpolation method; the equivalent stress range is equal to the basic fatigue strength range; drawing a perpendicular line perpendicular to the horizontal axis of the coordinate system through the reference point, and the perpendicular line intersects the target stress range distribution curve at a target point; determining the ordinate value of the target point by a numerical interpolation method; based on the ordinate value of the target point, determining the target fatigue strength range of the target notched component at the target failure cycle number by the following formula: ； In the formula, represents the target fatigue strength range; represents the ordinate value of the target point; represents the equivalent stress range; represents the basic fatigue strength range.

2. The method according to claim 1, characterized in that The determining the basic fatigue strength range of the smooth component at the target failure cycle number and the reference fatigue strength range of the reference notched component at the target failure cycle number for each of the plurality of set target failure cycle numbers includes: respectively obtaining the experimental fatigue strength ranges of the smooth component and the reference notched component at different experimental failure cycle numbers; for each target failure cycle number, based on the experimental fatigue strength ranges of the smooth component and the reference notched component at different experimental failure cycle numbers, using the numerical interpolation method to determine the basic fatigue strength range of the smooth component at the target failure cycle number and the reference fatigue strength range of the reference notched component at the target failure cycle number.

3. The method according to claim 1, wherein For each of the set multiple target failure cycle numbers, determining the basic fatigue strength range of the smooth part and the reference fatigue strength range of the reference notched part at the target failure cycle number further includes: Obtaining the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers respectively; Based on the experimental fatigue strength ranges of the smooth part and the reference notched part at different experimental failure cycle numbers, fitting and calibrating to obtain the SN curves in the form of Basquin equation analytical expressions for the smooth part and the reference notched part; Substituting the target failure cycle number into the SN curves in the form of Basquin equation analytical expressions for the smooth part and the reference notched part respectively, to obtain the basic fatigue strength range of the smooth part and the reference fatigue strength range of the reference notched part at the target failure cycle number.

4. The method according to claim 1, wherein Based on the reference fatigue strength range of the reference notched part and the reference stress range distribution curve at the target failure cycle number, determining the reference notch root stress range curve of the reference notched part under the action of the reference fatigue strength range through the following formula: ； In the formula, represents the stress range curve at the root of the reference notch; represents the reference fatigue strength range; represents the reference stress range distribution curve; represents the coordinate of any point on the coordinate axis pointing in the direction of the reference notch depth with the root of the reference notch on the reference notch component as the origin.

5. The method according to claim 1, wherein Predicting the predicted failure cycle number of the target notched part under a specific fatigue strength range based on multiple target failure cycle numbers and the target fatigue strength ranges at each target failure cycle number includes: Predicting the predicted failure cycle number of the target notched part under a specific fatigue strength range based on multiple target failure cycle numbers and the target fatigue strength ranges at each target failure cycle number through numerical interpolation; the numerical interpolation includes linear interpolation or parabolic interpolation.

6. The method according to claim 1, wherein After determining the target fatigue strength range of the target notched part at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, the method further includes: Based on the target fatigue strength range and the target stress range distribution curve, determining the target notch root stress range curve of the target notched part under the action of the target fatigue strength range through the following formula: ； In the formula, represents the stress range curve at the root of the target notch; represents the fatigue strength range of the target; represents the stress range distribution curve of the target; represents the coordinate of any point on the coordinate axis pointing in the direction of the target notch depth with the root of the target notch on the target notch component as the origin.

7. A unit load device for predicting the fatigue life of a notched component, characterized in that, The device includes: A building module for building a reference finite element model of a reference notched part and a target finite element model of a target notched part to be predicted; A loading module for applying a unit nominal load to the reference finite element model and the target finite element model respectively, to obtain a reference stress range distribution curve of the notch root of the reference notched part under the unit nominal load and a target stress range distribution curve of the notch root of the target notched part under the unit nominal load; A first determination module for determining, for each of the set multiple target failure cycle numbers, the basic fatigue strength range of the smooth part and the reference fatigue strength range of the reference notched part at the target failure cycle number; A second determination module, configured to determine a reference notch root stress range curve of the reference notch component under the action of the reference fatigue strength range based on the reference fatigue strength range of the reference notch component at the target failure cycle number and the reference stress range distribution curve; A third determination module, configured to determine the target fatigue strength range of the target notch component at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve; A prediction module, configured to predict the predicted failure cycle number of the target notch component under a specific fatigue strength range based on the multiple target failure cycle numbers and the target fatigue strength range at each target failure cycle number; When the third determination module is configured to determine the target fatigue strength range of the target notch component at the target failure cycle number based on the basic fatigue strength range, the reference notch root stress range curve, and the target stress range distribution curve, the third determination module is configured to: Plot the reference notch root stress range curve and the target stress range distribution curve in the same coordinate system; By means of a numerical interpolation method, find a reference point corresponding to the equivalent stress range on the reference notch root stress range curve; the equivalent stress range is equal to the basic fatigue strength range; Draw a perpendicular line perpendicular to the horizontal axis of the coordinate system through the reference point, and the perpendicular line intersects the target stress range distribution curve at a target point; By means of a numerical interpolation method, determine the ordinate value of the target point; Based on the ordinate value of the target point, determine the target fatigue strength range of the target notch component at the target failure cycle number through the following formula: ； In the formula, represents the target fatigue strength range; represents the ordinate value of the target point; represents the equivalent stress range; represents the basic fatigue strength range.

8. An electronic device, characterized in that, including: A processor, a memory, and a bus, where the memory stores machine-readable instructions executable by the processor. When the electronic device runs, the processor communicates with the memory through the bus. When the machine-readable instructions are run by the processor, the steps of a unit load method for predicting the fatigue life of a notch component according to any one of claims 1 to 6 are executed.

9. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium. When the computer program is run by a processor, the steps of a unit load method for predicting the fatigue life of a notch component according to any one of claims 1 to 6 are executed.

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