A simulation analysis method for gear tooth root cracks based on high cycle fatigue testing

Abstract

The present invention belongs to the technical field of gear design and analysis, and discloses a gear tooth root crack simulation analysis method based on high-cycle fatigue testing. The method comprises the following steps: fixing a test spur gear on a high-frequency fatigue testing machine via a fixture; performing a fatigue test on the test spur gear and collecting vibration signals and image data; analyzing the data to obtain test crack path data L1 and initial crack angle; establishing a finite element simulation model, performing static stress simulation to obtain stress distribution and extract the position of maximum bending stress at the tooth root; establishing a tooth root bending fatigue crack propagation simulation model to obtain simulated crack propagation path data L2; adjusting the crack implantation position and initial crack propagation angle parameters in the crack propagation simulation model, and repeating the simulation until an error condition is satisfied between L2 and L1; and performing tooth root crack propagation simulation based on the optimized crack propagation simulation model. The present invention can analyze the initiation and propagation evolution of spur gear tooth root cracks under multiple working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of gear design and analysis, and in particular relates to a gear tooth root crack simulation analysis method based on high cycle fatigue testing. Background Art

[0002] Gears are the most important and widely used power transmission structures in modern mechanical equipment. Depending on the operating environment and working conditions, the materials, processing technology, and structure of the selected gears all have specific requirements. Spur gears are the most widely used and typical common gear structure and are widely used in the gear transmission structures of fixed-axis gear trains and planetary gear trains. As a power transmission structure, the main working tooth surfaces of gears need to have reliable load-bearing capacity. When cracks or crack-like defects initiate on the tooth surface, gear failures such as pitting corrosion on the tooth surface and cracks on the tooth root can occur, resulting in a reduction in the gear's load-bearing capacity and even production safety accidents due to gear failure. Therefore, a large amount of research has been conducted both domestically and internationally on gear crack failures. Currently, related research mainly focuses on gear materials, processing technology, usage intensity, and identification and diagnosis methods after the failure occurs. There is little research on the regularity of gear crack initiation and propagation, and there is a lack of analysis on the contribution of different error and working conditions to the initiation and propagation of gear cracks. Most of the experiments conducted on tooth root cracks pre-implanted cracks at the root of healthy gear teeth using methods such as wire cutting. However, the characteristics of the pre-implanted cracks are quite different from those produced under actual service conditions, which is not conducive to the study of related crack characteristic laws.

[0003] In order to avoid the influence of human error caused by the crack implantation method on the study of crack initiation and propagation laws, it is necessary to find a gear tooth root crack simulation analysis method that is closer to the actual equipment operating conditions, so as to improve the reliability of the gear tooth root crack initiation and propagation law analysis. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a gear tooth root crack simulation analysis method based on high cycle fatigue test to realize the analysis of the initiation and expansion evolution rules of spur gear tooth root cracks under multiple working conditions.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a gear tooth root crack simulation analysis method based on high cycle fatigue test, comprising the following steps:

[0006] Step 1: Fix the test spur gear on the platform of the high-frequency fatigue testing machine with a fixture. At the same time, set up a high-speed camera to capture the root crack initiation process;

[0007] Step 2: Perform fatigue test on the test spur gear, and collect vibration signal data and image data during the test through vibration sensors;

[0008] Step 3: Analyze the vibration signal data and combine it with the image data to obtain the macro crack initiation time point and the gear tooth fracture time point; measure the fracture initiation position and path of the test spur gear to obtain the test crack path data L1 and determine the initial crack angle;

[0009] Step 4: Establish a finite element simulation model based on the geometric parameters and material parameters of the test spur gear. The finite element simulation model is a two-gear meshing model. Then, perform static stress simulation using the finite element simulation model to obtain stress distribution and extract the position of maximum bending stress at the tooth root.

[0010] Step 5: Establish a tooth root bending fatigue crack growth simulation model, use the coordinates of the maximum bending stress position of the tooth root as the crack implantation position, and use the initial crack angle as the initial crack growth angle. Implant a crack in the tooth root bending fatigue crack growth simulation model and perform a tooth root bending fatigue crack growth simulation calculation to obtain the crack simulation growth path data L2;

[0011] Step 6: Compare the test crack path data L1 and the crack simulation propagation path data L2 to determine whether the error condition is met. If not, adjust the crack implantation position and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model, repeat the simulation calculation and obtain the crack simulation propagation path data L2 until the obtained crack simulation propagation path data L2 meets the error condition with the test crack path data L1.

[0012] Step 7: Save the current values ​​of the crack implantation position and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model. Perform tooth root crack propagation simulations under different working conditions based on the optimized finite element tooth root bending fatigue crack propagation simulation model.

[0013] In step 1, the connections among the testing machine, the fixture and the test spur gear are all rigid connections.

[0014] In step 4, when establishing the finite element simulation model, the meshing gears only retain the rotational degree of freedom, and the loading load is set according to the test load.

[0015] In step 5, the simulated crack implantation mode is an elliptical crack, the crack tip extension area is a triangular unit grid, the crack iteration single growth length is less than 1 / 8 of the initial crack implantation length; and the crack propagation mode is expansion under static load.

[0016] In step 6, the specific method for determining whether the error condition is met is:

[0017] The average error and peak error of the experimental and simulated crack path curves are compared. If both are less than the error threshold, it is determined that the error condition is met.

[0018] In step 6, the error threshold is 15%.

[0019] Said step 4 also includes the following steps: optimizing the gear meshing point position in the iterative finite element simulation model according to the difference between the maximum bending stress position and the test crack initiation position, until the maximum bending stress position is consistent with the test crack initiation position.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention provides an experimental method for analyzing the natural initiation and propagation evolution of spur gear tooth root cracks under high-cycle fatigue conditions, as well as a method for constructing and verifying a high-precision model. First, a pulsed load is applied to the working surface of the test gear teeth using a high-frequency fatigue testing machine. Simultaneously, data from the crack propagation process is collected and analyzed using high-precision measuring instruments. Next, a precise static stress analysis model for the gear is established in ANSYS APDL software based on the test gear parameters. The gear meshing point is iteratively optimized to align the calculated maximum root bending stress position with the experimental crack initiation position, simulating the experimental loading and stress characteristics. Using the measured initial crack propagation angle parameters, a crack is implanted in ANSYS Workbench software at the optimized simulated maximum root bending stress position to construct a root bending fatigue crack propagation model. The crack propagation simulation model is optimized by iteratively adjusting the crack initiation position and initial crack propagation angle parameters. The experimental and simulation results are compared to verify the model's effectiveness and investigate the crack propagation patterns. Therefore, the present invention can intuitively, effectively, and rapidly simulate the natural root crack initiation process. The high-frequency testing machine's indenter can simulate the line contact force mode of a pair of meshing tooth surfaces during the meshing process of two teeth, effectively simulating the loading conditions for crack initiation, and largely avoiding the problems of artificially given crack initiation positions, initial crack propagation angles, and changes in the material mechanical properties of the crack propagation tip due to processing that exist in crack implantation methods such as wire cutting. During the test, high-speed cameras and vibration monitoring are used to effectively obtain the changing laws of the crack initiation and propagation process. This can be used to study the rapidly changing laws that cannot be directly observed in the test, such as the crack propagation rate in the crack initiation and propagation stages, the number of loading cycles at different states, and the characteristics of the crack propagation instability stage. This solves the problem of unobservable crack propagation laws in gear operation tests. The analysis results of the simulation model constructed based on the experimental and simulation comparative analysis method are more accurate and can be applied to the study of crack propagation laws under various manufacturing and installation errors and working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Flowchart of the high cycle fatigue test and model analysis method for the initiation and propagation evolution of spur gear tooth root cracks in the present invention;

[0023] Figure 2 Schematic diagram of the cooperation between the indenter and the test spur gear of the high-frequency fatigue testing machine of the present invention; wherein 1 is the test spur gear, and 2 is the indenter;

[0024] Figure 3 Schematic diagram of the structure of the sampling and analysis system in an embodiment of the present invention;

[0025] Figure 4 Schematic diagram of a photograph of a tooth root after fracture in a tooth root crack initiation and growth test in an embodiment of the present invention;

[0026] Figure 5 This is a process diagram of a tooth root crack initiation and propagation test captured by a high-speed camera in an embodiment of the present invention;

[0027] Figure 6 This is a vibration time domain signal diagram obtained by monitoring the tooth root crack initiation and growth test in an embodiment of the present invention;

[0028] Figure 7 This is a local image of the tooth root crack path measured under a fast rotating disk confocal microscope in an embodiment of the present invention;

[0029] Figure 8 This is a graph showing the experimental crack propagation path obtained from the tooth root crack initiation and propagation test in the present invention;

[0030] Figure 9 The ANSYS APDL finite element gear stress analysis model and stress result diagram in the present invention;

[0031] Figure 10 This is the ANSYS Workbench tooth root bending fatigue crack growth model diagram in the present invention;

[0032] Figure 11 The graphs of the experimental and simulated crack growth results in the present invention are shown, where (a) is the experimental crack trajectory graph and (b) is the simulated crack growth trajectory graph;

[0033] Figure 12 This is a comparison diagram of the crack propagation path curves of the test and simulation results in the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] like Figure 1As shown, an embodiment of the present invention provides a gear tooth root crack simulation analysis method based on high cycle fatigue test, comprising the following steps:

[0036] Step 1: Fix the test spur gear 1 on the platform of the high-frequency fatigue testing machine through a fixture. At the same time, install a vibration sensor on the fixture and set a high-speed camera to collect the root crack initiation process.

[0037] A high-speed camera, fixed at a fixed position and focused on the tooth root of the test gear, records the entire process of crack initiation and growth during the fatigue test. A vibration sensor records the time-series vibration acceleration amplitude during crack initiation and growth. Combined with the high-speed camera images, this provides data for analyzing the rapidly changing characteristics of the crack growth process.

[0038] like Figure 2 As shown in the figure, during the test, the pressure head of the high-frequency fatigue testing machine drops and contacts the teeth on both sides of the test spur gear 1. Figure 3 As shown, the test device also includes an image acquisition system and a vibration signal acquisition system. The image acquisition system, the vibration signal acquisition system and the test machine console are all connected to the simulation platform.

[0039] In this example, a C-type standard involute spur gear was used as the test and analysis object. The geometric parameters of the test spur gear are shown in Table 1. The test spur gear was fixed to the high-frequency fatigue testing machine platform using a special fixture. The fixture was fixed in a fully constrained form, and the testing machine, fixture, and test gear were all rigidly connected.

[0040] Table 1 Geometric parameters of the test spur gears

[0041] Parameter name Parameter value Normal modulus / mm 4 Number of teeth z 40 Pressure angle α / ° 20°

[0042] Tooth width b / mm 17 Tooth addendum height coefficient ha* / mm 1.0 Head clearance coefficient c* / mm 0.25 <![CDATA[Gear material density ρ / Kg / m 3 > 7980 Gear accuracy 5 Gear inner diameter (mm) 20

[0043] In this embodiment, the vibration sensor is arranged on the surface of the fixture.

[0044] Step 2: Perform a fatigue test on the test spur gear, and collect vibration signal data and image data during the test through a vibration sensor.

[0045] Specifically, in this embodiment, the image acquisition system and the vibration signal acquisition system are first turned on to record photos and vibration signal data of the crack initiation and expansion process; then, according to the set loading load of 77KN, the high-frequency fatigue testing machine pressure head is automatically pressed to the tooth surface of the gear tooth to be tested. The testing machine starts to load the load in the form of a pulse, and the test stop condition is that the gear tooth breaks or the number of loading times reaches 10 million times. After the test stops, stop taking pictures with the high-speed camera and collecting vibration signals, and record the test information. The information recorded by the test includes: the start and end time of the test, the ambient temperature, the ambient humidity, the loading load, the number of the gear tooth to be tested, and the final number of loading cycles. Figure 4 As shown, take a photo of the surface condition of the broken tooth and save the broken tooth.

[0046] Step 3: Analyze the vibration signal data and combine it with the image data to obtain the macro crack initiation time point and the gear tooth fracture time point; measure the tooth fracture initiation path of the test spur gear to obtain the test crack path data L1.

[0047] like Figure 5 、 Figure 6 As shown in FIG, there are image data measured by a high-speed camera and vibration signal data measured by a vibration sensor.

[0048] The specific method of step 3 is:

[0049] (1) Combining the vibration starting time of the high-frequency fatigue testing machine and the storage time of the photos of visible cracks taken by the high-speed camera, the number of crack loading cycles corresponding to the starting point of macro crack initiation and the tooth fracture failure point at this state were calculated, and the simulation analysis results were compared. After the macro crack appeared, the vibration acceleration fluctuated significantly, indicating that the gear tooth's ability to resist bending fatigue was significantly reduced.

[0050] (2) According to the sudden change characteristics of the vibration amplitude of the vibration time domain signal when the macro crack initiates, the test starts at t0 and the macro crack appears at t c1 The moment when the gear tooth fracture failure occurs is t c2 , the time from macro crack initiation to expansion to fracture failure can be obtained as t Δc . Combined with high-speed camera from t c1 Time to t c2 The number of image frames captured at all times, with a high-speed camera at a frame rate of 815 frames per second, is used to jointly estimate the macro crack initiation and fracture time.

[0051] (3) Measure the initiation of the test tooth fracture to obtain the test crack path data L1.

[0052] like Figure 7 As shown in the figure, it is the image data of the test broken tooth eruption position, as shown in the figure. Figure 8 Shown is the measured test crack path data L1, which is a data set of a series of coordinate points.

[0053] Step 4: Establish a finite element simulation model based on the geometric parameters and material parameters of the test spur gear. The finite element simulation model is a two-gear meshing model. Then, perform static simulation using the finite element simulation model to obtain stress distribution and extract the position of maximum bending stress at the tooth root.

[0054] like Figure 9 As shown, in this embodiment, a model is established in ANSYS APDL finite element software according to the test spur gear geometry and material parameters described in Table 1, and simulation analysis of tooth root bending stress is performed by setting simulation conditions with reference to the test conditions.

[0055] In this embodiment, the established finite element model is a two-gear meshing model, and the simulation model is divided into an ANSYS APDL static stress simulation model (used to optimize the gear meshing loading position) and an ANSYS Workbench tooth root bending fatigue crack propagation simulation model; the gear geometric parameters, material properties, loading and constraint methods in the two models are the same.

[0056] In this embodiment, referring to the experimental loading load of 77KN and the position relationship of the indenter, the simulation process simulates the loading load in the form of a torque of 1025N·m, and the loading position is the coupling node of the inner hole unit of the driving wheel;

[0057] In this embodiment, other constraints of the finite element simulation model include: the inner hole degree of freedom of the driven wheel is fully constrained, and the driving wheel only retains the axial rotational degree of freedom to ensure torque loading;

[0058] Step 6.4: Perform static stress simulation in ANSYS APDL based on the finite element model of a pair of meshing gears to obtain the stress solution results, extract the position parameters of the maximum bending stress at the tooth root, and compare them with the Figure 7 Comparison of experimental crack initiation positions. By iteratively optimizing the simulated meshing point position, the maximum bending stress position of the simulated tooth root is ensured to be the same as the experimental crack initiation position. The comparison values ​​of the experimental and simulated initiation positions (in the same coordinate system) are shown in Table 2.

[0059] Table 2 Comparison of crack initiation position coordinates

[0060]

[0061] Furthermore, step 4 also includes the following steps: optimizing the gear meshing point position in the iterative finite element simulation model according to the difference between the maximum bending stress position and the test crack initiation position, until the maximum bending stress position is consistent with the test crack initiation position.

[0062] Step 5: Use ANSYS Workbench, a finite element analysis software, to create a simulation model for tooth root bending fatigue crack growth. Using the initiation location of the test spur gear as a reference, the maximum bending stress coordinates calculated in the stress simulation are used as the implanted crack location. Then, based on the experimental crack growth angle, a crack is implanted and the tooth root bending fatigue crack growth simulation is performed to obtain the simulated crack growth path data, L2.

[0063] Specifically, if Figure 10 As shown, in this embodiment, the crack propagation simulation conditions were set using the finite element analysis software ANSYS Workbench Fracture Analysis module. The implanted crack type was the elliptical crack type from the Workbench Fracture Analysis module. The crack tip propagation region consisted of a triangular element mesh, and the crack growth length per iteration should be less than 1 / 8 of the initial implanted crack length. The crack propagated under static load, with only rotational degrees of freedom retained in the meshing gears. Based on the test load of 77 kN and the distance from the loading point to the gear center, a simulated load of 1025 N·m torque was calculated. The torque was applied to the inner tooth surface of the driving gear.

[0064] Specifically, in this embodiment, when simulating tooth root crack growth, not only the simulated crack growth path data L2 is obtained, but also the crack growth fatigue life. Specifically, the crack growth simulation analysis results are imported into the ANSYS Workbench Fatigue Analysis Module (nCode). After setting the gear material parameters and loading the bending stress load spectrum results from the crack growth simulation, the Goodman stress correction method is used to calculate the fatigue life to obtain the simulated crack growth fatigue life. The crack growth fatigue life results show that the simulated crack growth fatigue life is 191,507 cycles, while the experimental fatigue loading cycle number is 187,014.

[0065] Step 6: To minimize the impact of uncontrollable factors such as test gear material defects, test installation, and measurement errors on the comparison between the simulation model and the test model, the test crack path data L1 and the simulated crack propagation path data L2 are compared. An error rate range is determined to determine the consistency between the simulation model and the test model. If the error rate exceeds the error threshold, the crack initiation location and initial crack angle parameters of the finite element simulation model are slightly adjusted. Steps 4 to 6 are repeated until the test crack path data L1 and the simulated crack propagation path data L2 meet the error rate condition, resulting in the optimized finite element tooth root bending fatigue crack propagation simulation model.

[0066] Specifically, in step 6, the specific method for determining whether the error rate condition is met is:

[0067] Compare the average error and peak error of the polynomial curve fitting test and the simulated crack path curve, and calculate the error rate of the average error and peak error. If both are less than the error threshold, it is determined that the error condition is met. Specifically, the error threshold can be 15%.

[0068] In this implementation, the error rate calculation formulas for the average error and peak error are:

[0069]

[0070] Where ε represents the error rate between the test and simulation crack growth paths, X represents the test crack path data, and X′ represents the simulation crack path data. The validity of the tooth root bending fatigue crack growth model is verified. By extracting the test and simulation crack growth path data sets and normalizing them, the starting points of the two crack growth curves are both (0, 0), as shown in Figure 11 、 Figure 12 The simulation model has high accuracy, and the simulation results can be used to analyze the experimental laws of tooth root bending fatigue crack growth.

[0071] Step 7: Save the current values ​​of the crack implantation position and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model. Based on the optimized finite element tooth root bending fatigue crack propagation simulation model, perform root crack propagation simulations for various influencing factors. Specifically, the optimized finite element tooth root bending fatigue crack propagation simulation model can be used to simulate crack propagation under various influencing factors, such as tooth surface roughness, gear manufacturing, and installation errors.

[0072] According to the maximum circumferential force theory, the experimental crack initiation location and initial crack propagation angle are primarily affected by the load application location and direction. In this invention, the gear meshing position in the iterative simulation model is optimized using the experimental crack initiation location. The difference between the crack simulation propagation path data L2 and the experimental crack path data L1 is used to adjust the crack implantation location and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model, making the resulting tooth root bending fatigue crack propagation simulation model closer to the actual model. The optimized finite element tooth root bending fatigue crack propagation simulation model can then be used to simulate tooth root crack propagation under different operating conditions. Specifically, the experimentally obtained crack initiation location and initial crack initiation angle can be used to simulate crack propagation under various influencing factors, such as tooth surface roughness, gear manufacturing, and installation errors, thereby improving model accuracy.

[0073] The crack initiation position and initial crack propagation angle of the test gear are affected by the load loading position, subsurface defects of the tooth root and measurement errors. There is a small deviation between the test crack initiation position and the calculated bending stress maximum position. The simulation loading conditions simulate the meshing process of two teeth. Unlike the test loading method, the simulated meshing position and torque values ​​are obtained by analyzing the test load conditions and calculating. After multiple iterations of optimization of the relevant parameters of the crack propagation model in the embodiment (gear meshing position, crack initiation position, crack propagation angle), the crack propagation process trends of the test and simulation results are consistent. The simulation model can be used to simulate the crack fatigue propagation law under different manufacturing and installation errors and working conditions.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gear tooth root crack simulation analysis method based on high cycle fatigue test, characterized in that: The following steps are involved: Step 1: Fix the test spur gear on the platform of the high-frequency fatigue testing machine with a fixture. At the same time, set up a high-speed camera to capture the root crack initiation process; Step 2: Perform fatigue test on the test spur gear, and collect vibration signal data and image data during the test through vibration sensors; Step 3: Analyze the vibration signal data and combine it with the image data to obtain the macro crack initiation time point and the gear tooth fracture time point; measure the fracture initiation position and path of the test spur gear to obtain the test crack path data L1 and determine the initial crack angle; Step 4: Establish a finite element simulation model based on the geometric parameters and material parameters of the test spur gear. The finite element simulation model is a two-gear meshing model. Then, perform static stress simulation using the finite element simulation model to obtain stress distribution and extract the position of maximum bending stress at the tooth root. Step 5: Establish a tooth root bending fatigue crack growth simulation model, use the coordinates of the maximum bending stress position of the tooth root as the crack implantation position, and use the initial crack angle as the initial crack growth angle. Implant a crack in the tooth root bending fatigue crack growth simulation model and perform a tooth root bending fatigue crack growth simulation calculation to obtain the crack simulation growth path data L2; Step 6: Compare the test crack path data L1 and the crack simulation propagation path data L2 to determine whether the error condition is met. If not, adjust the crack implantation position and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model, repeat the simulation calculation and obtain the crack simulation propagation path data L2 until the obtained crack simulation propagation path data L2 meets the error condition with the test crack path data L1. Step 7: Save the current values ​​of the crack implantation position and initial crack propagation angle parameters in the tooth root bending fatigue crack propagation simulation model. Perform tooth root crack propagation simulations under different working conditions based on the optimized tooth root bending fatigue crack propagation simulation model.

2. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 1, characterized in that: In step 1, the connections among the testing machine, the fixture and the test spur gear are all rigid connections.

3. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 1, characterized in that: In step 4, when establishing the finite element simulation model, the meshing gears only retain the rotational degree of freedom, and the loading load is set according to the test load.

4. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 1, characterized in that: In step 5, the simulated crack implantation mode is an elliptical crack, the crack tip extension area is a triangular unit grid, the crack iteration single growth length is less than 1 / 8 of the initial crack implantation length; and the crack propagation mode is expansion under static load.

5. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 1, characterized in that: In step 6, the specific method for determining whether the error condition is met is: The average error and peak error of the experimental and simulated crack path curves are compared. If both are less than the error threshold, it is determined that the error condition is met.

6. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 5, characterized in that: In step 6, the error threshold is 15%.

7. The gear tooth root crack simulation analysis method based on high cycle fatigue test according to claim 1, characterized in that: Said step 4 also includes the following steps: optimizing the gear meshing point position in the iterative finite element simulation model according to the difference between the maximum bending stress position and the test crack initiation position, until the maximum bending stress position is consistent with the test crack initiation position.

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