Ultrahigh-cycle fatigue test method

Abstract

The invention relates to the technical field of fatigue tests, and discloses an ultra-high cycle fatigue test method, which is suitable for an ultra-high cycle fatigue test verification system, and comprises the following steps: step 1, determining an initial stress value and an axial first-order resonant frequency of a test piece; step 2, the signal acquisition control device controls the vibration table to vibrate according to a first-order resonance frequency which is less than or equal to 3000Hz; step 3, collecting vibration data by the signal collection control device until the test piece is broken, and sending the vibration data to a verification device; 4, changing the initial stress value, and repeating the steps 2 to 3; after multiple groups of vibration data are obtained, the test is stopped; and step 5, performing stress analysis on the vibration data by the verification device to obtain a test fatigue ultimate strength value of the test piece. According to the ultrahigh-cycle fatigue test method and verification system provided by the invention, the defect that the current ultrahigh-cycle fatigue performance test period is long can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of fatigue testing, and in particular to an ultra-high cycle fatigue testing method. Background Art

[0002] During the operation of the aircraft, the fan, blades or disc of the engine are easily subjected to low-load and high-frequency vibration stress, which causes fatigue of the metal material. Fatigue is a failure form of metal materials under alternating stress. It manifests as the sudden fracture of metal materials after a certain number of cyclic loads at a stress level far below the static strength limit. In this regard, metal material fatigue tests can be used to understand the fatigue performance of metal materials under different stress levels.

[0003] Existing fatigue tests for metal materials usually use electro-hydraulic servo fatigue testing machines and electromagnetic resonance high-frequency fatigue testing machines. Electro-hydraulic servo fatigue testing machines have a large load capacity and test range, and can adapt to different types of test requirements, but the test frequency is generally within the range of 100Hz. Electromagnetic resonance high-frequency fatigue testing machines are generally suitable for tests in high-frequency vibration environments. The frequency is determined according to the stiffness of the test piece and is generally below 200Hz. Since the cycle life of ultra-high cycle fatigue tests is generally 10 7 The above engine design specifications require the compressor blades to have a lifespan of 10 9 If an electro-hydraulic servo fatigue testing machine or an electromagnetic resonance high-frequency fatigue testing machine is used to test the fatigue limit life of the test piece, the test cycle will be longer.

[0004] Therefore, there is an urgent need for an ultra-high cycle fatigue test method that can meet the requirements of ultra-high cycle fatigue testing and has a high fatigue test accuracy. Summary of the invention

[0005] In view of this, the present invention provides a very high cycle fatigue test and method to solve the problem of long cycle of very high cycle fatigue test in existing technology.

[0006] In a first aspect, the present invention provides a very high cycle fatigue test method, which is applicable to a very high cycle fatigue test verification system, the system comprising: a vibration table axial vibration fatigue test system and a verification device, the vibration table axial vibration fatigue test system comprising: an axial vibration table, a test piece, a test fixture, a signal acquisition control device, and a strain gauge; wherein the test fixture is arranged on the axial vibration table, the test fixture is used to fix the test piece, a strain gauge is arranged on the test piece, and the signal acquisition control device is electrically connected to the axial vibration table, the strain gauge and the verification device respectively; the method comprises:

[0007] Step 1, determining the initial stress value and the first-order axial resonance frequency of the test piece;

[0008] Step 2, the signal acquisition control device controls the axial vibration table to vibrate according to the resonance frequency, wherein the resonance frequency is less than or equal to 3000 Hz;

[0009] Step 3, the signal acquisition control device collects vibration data until the test piece breaks, and sends the vibration data to the verification device;

[0010] Step 4, change the initial stress value, repeat the above steps 2 to 3; after obtaining multiple sets of vibration data, stop the test;

[0011] Step 5: The verification device performs stress analysis on the vibration data to obtain the test fatigue limit strength value of the test piece.

[0012] In an optional implementation, after obtaining the test fatigue limit strength value of the test piece, the method further includes:

[0013] The verification device obtains a reference fatigue limit strength value consistent with the test piece material obtained by other preset fatigue test methods;

[0014] The error between the test fatigue limit strength value and the reference fatigue limit strength value is calculated, and the error value is used to verify the shaking table axial vibration fatigue test system.

[0015] In an optional implementation, when the error value is less than a preset threshold, it is determined that the accuracy of the vibration table axial vibration fatigue test system is normal.

[0016] In an optional implementation, other preset fatigue test methods include: a fatigue test method based on an electromagnetic resonance high-frequency fatigue testing machine, or a fatigue test method based on an electro-hydraulic servo fatigue testing machine.

[0017] In an optional implementation, the test piece is designed after static analysis, buckling analysis, and modal analysis.

[0018] In an optional implementation, the test fixture is designed after strength verification and modal analysis.

[0019] In an optional embodiment, the temperature of the test piece is monitored while the axial vibration table is vibrating according to the resonant frequency.

[0020] In an optional implementation, the vibration data includes: stress value, strain value, and cycle number of the test piece, and stress analysis is performed on the vibration data, including:

[0021] Establish SN curve based on stress value, strain value and cycle number;

[0022] Based on the SN curve, the test fatigue limit strength value is determined.

[0023] The beneficial effects of the present invention are as follows:

[0024] The test frequency of the vibration table axial vibration fatigue test system can be adjusted according to the vibration table's excitation capacity, and the test frequency required by the design can be achieved through the test piece design and fixture design, and the test frequency can reach up to 3000Hz. The ultra-high cycle fatigue test method and system provided by the present invention can effectively solve the current disadvantage of long ultra-high cycle fatigue performance test cycle.

[0025] By comparing and analyzing the fatigue limit strength values ​​and fracture metallographic structures obtained by the two test methods, the fatigue failure behaviors are basically consistent, and there is no fundamental change in the fracture mechanism. The fatigue fracture is mainly surface cracking, which verifies the effectiveness of the vibration table ultra-high cycle fatigue test method. At the same time, the fatigue limit estimates of the two test methods are within the 5% error range, verifying the consistency between the fatigue test of the ultra-high cycle fatigue test system and the fatigue test of the traditional electromagnetic resonance. For the ultra-high cycle fatigue performance test of engine metal parts (10 9 ) and research provided methods to support the high-cycle fatigue design of aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a schematic structural diagram of a test fixture according to an embodiment of the present invention;

[0028] Figure 2 is a schematic flow chart of a very high cycle fatigue test method according to an embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of a labor test data lifting pair according to an embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of a lifting and lowering result table according to an embodiment of the present invention;

[0031] Figure 5 It is a flow chart of a very high cycle fatigue test verification system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] During the service of aircraft engines, fans, blades or disks are susceptible to low-load and high-frequency vibration stress, and the cycle period is usually 10 7 Above. Fatigue is a form of failure of metal materials under alternating stress. It manifests itself as a sudden break of the material after a certain number of cyclic loads at a stress level far below the static strength limit. High-cycle fatigue testing is usually carried out on a special fatigue testing machine by applying periodic tension-compression and tension-tension cyclic loads and setting the frequency of the cyclic loads. Under the action of cyclic loads, metal materials break under cyclic loads. Through metallographic inspection of the fracture of the test piece, fatigue bands were found on the fracture, verifying that the test piece had fatigue fracture under the action of cyclic loads.

[0034] Fatigue failure is a common form of failure in modern engineering materials. Determining the fatigue performance of engineering materials is of great significance for the design and life prediction of engineering structures. Usually, the maximum number of cycles for high-cycle fatigue performance testing is 1×10 7 cycles, fatigue life exceeds 1×10 7 After (3×10 7 ~10 9 The ultra-high cycle fatigue test is called ultra-high cycle fatigue. The ultra-high cycle fatigue life is long, and the fatigue life dispersion is large at low stress levels. The ultra-high cycle fatigue test using traditional electromagnetic resonance fatigue testing machines is costly and has a long test cycle. At present, a mature ultra-high cycle fatigue test system and test method have not yet been established.

[0035] In view of this, according to an embodiment of the present invention, an embodiment of an ultra-high cycle fatigue test method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0036] In this embodiment, a very high cycle fatigue test method is provided, which can be performed by a very high cycle fatigue test verification system. The system includes: a vibration table axial vibration fatigue test system and a verification device. Figure 1As shown, the vibration table axial vibration fatigue test system includes: an axial vibration table (not shown in the figure), a test piece, a test fixture, a signal acquisition control device (not shown in the figure), and a strain gauge (not shown in the figure); wherein the test fixture is arranged on the vibration table, the test fixture is used to fix the test piece, a strain gauge is arranged on the test piece, and the signal acquisition control device is electrically connected to the axial vibration table, the strain gauge, and the verification device respectively. Further, the signal acquisition control device includes: a vibration controller, an acceleration sensor, etc., and the verification device includes a dynamic signal analyzer, a recording software device, an electro-hydraulic servo fatigue tester or an electromagnetic resonance fatigue tester, a server or a terminal device, etc. Figure 2 is a flow chart of a very high cycle fatigue test method according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0037] Step 1, determine the initial stress value and the first-order axial resonance frequency of the test piece. Specifically, after the test fixture is assembled, install it on the axial vibration table, tighten all the mounting bolts, and then adjust the test fixture. Monitor the stress data according to the strain gauge set on the test piece, and adjust the stress value of the test piece through the signal amplifier in the signal acquisition control device. Furthermore, the resonance frequency can be set by the vibration controller in the signal acquisition control device. The sweep frequency test can use 0.5g input acceleration, the input waveform is a sine wave, the resonance frequency is 1Oct / min, and the sweep frequency range is up to the first-order axial natural frequency of the test piece and the test fixture. The purpose is to obtain the axial first-order resonance frequency of the test fixture.

[0038] The frequency sweep test can also use 0.3g input acceleration and a resonance frequency of 0.5Oct / min. The frequency sweep range is determined according to the resonance frequency of the test piece. After the frequency sweep is completed, a fixed-frequency resonance test is performed according to the resonance frequency of the system resonance point. During the test, the acceleration sensor in the signal acquisition control device is used to monitor the response acceleration amplitude of the test piece and collect the response acceleration.

[0039] Two strain gauges can be symmetrically attached to the working section of the test piece, and the strain of the test piece can be collected using a dynamic signal test and analysis system. According to the measured acceleration, the stress value of the working section can be calculated by F=ma, σ=F / A, where A is the stress area, and compared with the measured stress value to verify the rationality of the stress conversion.

[0040] Step 2: The vibration controller in the signal acquisition control device controls the axial vibration table to vibrate according to the resonance frequency, wherein the resonance frequency is less than or equal to 3000 Hz.

[0041] It should be noted that the traditional fatigue testing machine is not suitable for ultra-high frequency vibration environment, generally below 200Hz, and cannot withstand higher vibration frequencies, resulting in a longer test cycle. In this embodiment, an axial vibration table is used, which can withstand a resonance frequency of up to 3000Hz. The use of ultra-high frequency resonance frequency can effectively shorten the test cycle.

[0042] Step 3, the vibration controller in the signal acquisition control device collects vibration data until the test piece breaks, and sends the vibration data to the dynamic signal analysis and recording software device in the verification device.

[0043] When the response acceleration suddenly decreases, the test piece breaks, or the test piece reaches the specified cycle life without breaking, it proves that the test piece has cracks or fails, and the test is stopped. At the same time, vibration data such as stress size S, number of cycles N, and frequency Hz are recorded. The vibration data is sent to the verification device for data analysis and accuracy verification.

[0044] Step 4, change the initial stress value and repeat the above steps 2 to 3; after obtaining multiple sets of vibration data, stop the test.

[0045] In this embodiment, a step-by-step load loading method is used to perform a vibration fatigue test on the test piece. The test piece is fixed on a vibration table. During the test, the excitation frequency of the vibration table is controlled by a sine signal generator. Therefore, it is sufficient to make the frequency of the signal generated by the sine signal generator equal to the natural frequency of the test piece. The output voltage amplitude of the signal generator is gradually increased until the test load amplitude is reached, and the adjustment is stopped. The test process then enters the load holding stage, and data is recorded every 10-15 minutes.

[0046] The lifting method is used to determine 3 pairs of effective test lifting pairs, and the corresponding number of cycles is 3*10 7 . Fatigue test data up and down reference Figure 3 As shown, the lifting and lowering result table refers to Figure 4 The test fatigue limit strength value is

[0047] Step 5: The server or terminal device in the verification device performs stress analysis on the vibration data to obtain the test fatigue limit strength value of the test piece.

[0048] The current high-frequency fatigue testing machine's test principle is electromagnetic resonance, which determines the test frequency of the fatigue specimen by the stiffness of the entire fixture and the specimen or the resonant frequency of the two. The test frequency of this method is determined by the material itself and cannot be changed. However, the frequency of general metal materials is about 80Hz-150Hz. The general ultra-high cycle fatigue life is set to 10 9 , if calculated at 100Hz, one cycle is 0.01S, 109 The cycle takes about 277 hours. Since it takes about 50 specimens to test the SN curve of a material under a certain stress ratio and stress concentration factor, and it takes 570 days to test an SN curve, this method results in a long test cycle and high cost.

[0049] The ultra-high cycle fatigue test method and system provided by the present invention can effectively solve the current disadvantage of long ultra-high cycle fatigue performance test cycle. The test frequency of the vibration table axial vibration fatigue test system can be adjusted according to the excitation capacity of the vibration table, and the test frequency required by the design can be achieved through the test piece design and fixture design. The test frequency can reach up to 3000Hz, and the test results can maintain 95% consistency with the results of the electromagnetic resonance high-frequency fatigue testing machine. The test system and method can greatly shorten the test time and save test costs.

[0050] In some optional implementations, after obtaining the test fatigue limit strength value of the test piece, the method further includes:

[0051] The verification device obtains a reference fatigue limit strength value consistent with the test piece material obtained by other preset fatigue test methods;

[0052] The error between the test fatigue limit strength value and the reference fatigue limit strength value is calculated, and the error value is used to verify the shaking table axial vibration fatigue test system.

[0053] The ultra-high cycle fatigue test system provided by the present invention can effectively solve the current disadvantage of long ultra-high cycle fatigue performance test cycle, but it also requires a feasible verification system to verify its rationality, thereby speeding up the test cycle of basic fatigue performance data and reducing the error of compressor blade anti-fatigue design.

[0054] Specifically, the test results of the ultra-high cycle fatigue test system can be compared with the test results of the electromagnetic resonance high-frequency fatigue test machine. By comparing and analyzing the fatigue limit strength values ​​and fracture metallographic structures obtained by the two test methods, the fatigue failure behaviors are basically consistent, and there is no fundamental change in the fracture mechanism. The fatigue fracture is mainly surface cracking, which verifies the effectiveness of the ultra-high cycle fatigue test method of the vibration table. At the same time, the fatigue limit estimates of the two test methods are within the 5% error range, verifying the consistency between the fatigue test of the ultra-high cycle fatigue test system and the fatigue test of the traditional electromagnetic resonance. For the ultra-high cycle fatigue performance test of engine metal parts (10 9 ) and research provided methods to support the high-cycle fatigue design of aircraft engines.

[0055] In this embodiment, an ultra-high cycle fatigue test system has been used to test and analyze the ultra-high cycle fatigue ultimate strength of a certain type of compressor titanium alloy blade, and a comparative analysis has been conducted with the fatigue test results of an electromagnetic resonance high-frequency fatigue tester, verifying the effectiveness and consistency of the ultra-high cycle fatigue strength tested by the ultra-high cycle fatigue test system. The ultimate strength of the ultra-high cycle fatigue life of the engine compressor titanium alloy blade was obtained, providing basic design performance data support for the high-cycle fatigue resistance design of this type of blade. This has laid the foundation for the subsequent engineering application of ultra-high cycle fatigue SN fatigue curve testing of other metal materials.

[0056] In some optional implementations, when the error value is less than a preset threshold, it is determined that the accuracy of the vibration table axial vibration fatigue test system is normal.

[0057] The preset threshold value may be 5%. When the fatigue limit strength values ​​of the two test methods are within the 5% error range, the consistency between the fatigue test of the ultra-high cycle fatigue test system and the fatigue test of the traditional electromagnetic resonance is verified.

[0058] In some optional implementations, other preset fatigue test methods include: a fatigue test method based on an electromagnetic resonance high-frequency fatigue testing machine, or a fatigue test method based on an electro-hydraulic servo fatigue testing machine.

[0059] In this embodiment, the ultra-high cycle fatigue test verification system performs an axial resonance fatigue test, and compares and analyzes the difference between the test results of the electromagnetic resonance fatigue test performed by the high frequency fatigue testing machine or the test results of the electro-hydraulic servo fatigue testing machine.

[0060] Taking the electromagnetic resonance high-frequency fatigue testing machine test as an example, first select the standard sample, and conduct fatigue test on the high-frequency fatigue testing machine. Select 35% of the tensile strength of the material to conduct fatigue test on the first sample. If it reaches 3*10 7 If the test fails after 3*10 cycles, the test is over, and the stress is increased by one level to test the second sample. If the test fails after 3*10 cycles, the stress is increased by one level to test the third sample. If the stress does not reach 3*10 7 If the test fails after the number of cycles, the stress level is reduced to the first level and the fourth specimen is tested. This process is repeated until there are at least 3 pairs of valid test results. According to the statistical method of fatigue test data of metal materials, statistical analysis is performed and 3*10 is calculated. 7 At the same time, the designed non-standard specimens are mounted on the vibration table through the fixture and tested 3*10 according to the above lifting method. 7 The fatigue limit strength value of the sample under fatigue life is also calculated by statistical analysis of data to obtain 3*10 7The fatigue limit strength value of the sample under the fatigue life is compared with the fatigue limit strength values ​​of the two tests. If the fatigue strength values ​​of the two tests are within 5% error, it can be considered that the strength value obtained by the ultra-high cycle fatigue test system and the strength value obtained by the conventional electromagnetic resonance fatigue testing machine have good consistency.

[0061] In some optional implementations, the test piece is designed after static analysis, buckling analysis, and modal analysis.

[0062] In this embodiment, the fatigue test piece design principle in the "Method for Force-Controlled Constant Amplitude Axial Fatigue Test of Metallic Materials" can be referred to to preliminarily determine the dimensions of the clamping end, transition section, and working section of the test piece. After the preliminary design, the test piece is subjected to static analysis, buckling analysis, and modal analysis based on the material parameters of the test piece (elastic modulus, Poisson's ratio, density). The first-order axial natural frequency of the test piece is designed, and the design frequency is temporarily set at 1000Hz. Referring to the standard test piece form, the size parameters of the test piece are modified according to the designed natural frequency value. When the test piece meets the static and buckling requirements, the fixture design is then performed.

[0063] In some optional embodiments, the test fixture is designed after strength verification and modal analysis.

[0064] The fixture design determines the natural frequency and limit load according to the test requirements. The first-order axial natural frequency of the fixture must be greater than the first-order axial natural frequency of the test piece. At the same time, to avoid fatigue damage to the fixture during the test, the limit load of the fixture in the vibration fatigue test should be less than the fatigue limit load of the fixture material.

[0065] The test frequency of the vibration table axial vibration fatigue test system can be adjusted according to the vibration table's excitation capacity, and the test frequency required by the design can be achieved through the test piece design and fixture design. The test frequency can reach up to 3000Hz, and the test results can maintain 95% consistency with the results of the electromagnetic resonance high-frequency fatigue tester. This test system and method can greatly shorten the test time and save test costs.

[0066] In this embodiment, for the ultra-high cycle fatigue performance test and acquisition of engine compressor blade materials, refer to Figure 5As shown in the figure, suitable non-standard test pieces and test piece fixtures are designed, and a very high cycle fatigue test system is established through strength verification and modal analysis. The axial resonance fatigue test of the test piece is carried out on this test system, and the fatigue limit data and fracture metallographic structure of the two test methods are compared and analyzed to verify the effectiveness of the vibration table very high cycle fatigue test method. The test results of the two methods are within the error range of 5%, which verifies the consistency and reliability of the vibration table-based very high cycle fatigue test method. It can provide a methodological guide for the test acquisition of the SN curve of the very high cycle fatigue performance of the subsequent engine compressor blades.

[0067] In some optional embodiments, the temperature of the test piece is monitored while the axial vibration table vibrates according to the resonant frequency. During the test, the temperature of the working section of the test piece is measured, and by monitoring the temperature changes, fatigue and damage of the material can be identified early. If the temperature rises abnormally, it may indicate microcracks or other damage inside the material. In the sweep frequency vibration test of the vibration table, monitoring the temperature can not only improve the safety and accuracy of the experiment, but also provide important support for material performance analysis, design optimization and the development of new materials.

[0068] In some optional implementations, the vibration data includes: stress value, strain value, and cycle number of the test piece, and stress analysis of the vibration data includes:

[0069] Establish SN curve based on stress value, strain value and cycle number;

[0070] Based on the SN curve, the test fatigue limit strength value is determined.

[0071] At present, fatigue tests on standard specimens are usually carried out according to the "Methods for Axial Fatigue Test of Metallic Materials". The low-cycle fatigue life range (10 3 -10 5 ), high cycle fatigue life segment (10 5 -10 7 ) fatigue life, and the SN fatigue curve of metal materials is obtained by fitting the stress S and cycle life N. 9 The fatigue limit strength of the compressor blades is usually calculated by the SN fatigue curve (10 7 ). In this embodiment, the ultra-high cycle fatigue test method is used to provide an ultra-high cycle SN fatigue curve (10 9 ), which provides a methodological guide for the test acquisition of the SN curve of the ultra-high cycle fatigue performance of subsequent engine compressor blades.

[0072] In this embodiment, an ultra-high cycle fatigue test system is established with reference to the vibration table axial vibration fatigue test system. The ultra-high cycle fatigue test system is composed of the vibration table axial vibration fatigue test system and the verification device. The vibration table axial vibration fatigue test system is composed of a vibration test system and an experimental test system. The vibration test system is composed of a power amplifier and a sinusoidal signal generator. The experimental test system is composed of a vibration strain tester, a vibration acceleration sensor, a charge amplifier, a dynamic signal analyzer, and dynamic signal analysis and recording software. All devices and equipment that can realize signal acquisition and control can be used without any special restrictions.

[0073] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A very high cycle fatigue test method, characterized in that: The method is applicable to a very high cycle fatigue test verification system, the system comprising: a vibration table axial vibration fatigue test system and a verification device, the vibration table axial vibration fatigue test system comprising: an axial vibration table, a test piece, a test fixture, a signal acquisition control device, and a strain gauge; wherein the test fixture is arranged on the axial vibration table, the test fixture is used to fix the test piece, the strain gauge is arranged on the test piece, and the signal acquisition control device is electrically connected to the axial vibration table, the strain gauge and the verification device respectively; the method comprises: Step 1, determining the initial stress value and the axial first-order resonance frequency of the test piece; Step 2, the signal acquisition control device controls the axial vibration table to vibrate according to the resonance frequency, wherein the resonance frequency is less than or equal to 3000 Hz; Step 3, the signal acquisition control device collects vibration data until the test piece breaks, and sends the vibration data to the verification device; Step 4, changing the initial stress value, repeating the above steps 2 to 3; after obtaining multiple sets of vibration data, stopping the test; Step 5: The verification device performs stress analysis on the vibration data to obtain the test fatigue limit strength value of the test piece.

2. The method according to claim 1, characterized in that After obtaining the test fatigue limit strength value of the test piece, the method further includes: The verification device obtains a reference fatigue limit strength value obtained by other preset fatigue test methods and consistent with the material of the test piece; An error value between the test fatigue limit strength value and the reference fatigue limit strength value is calculated, and the error value is used to verify the vibration table axial vibration fatigue test system.

3. The method according to claim 2, characterized in that When the error value is less than a preset threshold, it is determined that the accuracy of the vibration table axial vibration fatigue test system is normal.

4. The method according to claim 2, characterized in that: The other preset fatigue test methods include: a fatigue test method based on an electromagnetic resonance high-frequency fatigue testing machine, or a fatigue test method based on an electro-hydraulic servo fatigue testing machine.

5. The method according to claim 1, characterized in that The test piece is designed after static analysis, buckling analysis and modal analysis.

6. The method according to claim 1, characterized in that The test fixture is designed after strength verification and modal analysis.

7. The method according to claim 1, characterized in that The temperature of the test piece is monitored while the axial vibration table vibrates according to the resonant frequency.

8. The method according to claim 1, characterized in that The vibration data includes: stress value, strain value, and cycle number of the test piece, and the stress analysis of the vibration data includes: Establishing an SN curve based on the stress value, the strain value, and the number of cycles; Based on the SN curve, the test fatigue limit strength value is determined.

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