Bearing channel rolling contact fatigue test device and use method thereof

Abstract

The invention belongs to the field of rolling contact fatigue tests, and particularly relates to a bearing channel rolling contact fatigue test device and a use method thereof. According to the technical scheme, the bearing channel rolling contact fatigue test device comprises a rack, a power driving assembly, a loading assembly and a movable workbench assembly, and the power driving assembly, the loading assembly and the movable workbench assembly are arranged in the rack; a test piece is installed on the movable workbench assembly, the power driving assembly and the movable workbench assembly move in a matched mode, so that a bearing channel of the test piece makes contact with a rolling body of the loading assembly, and a rolling contact fatigue test is conducted on the bearing channel through the rolling body. According to the invention, the rolling contact fatigue state between the ball bearing rolling body and the bearing channel can be simulated, the loading requirement of the ball bearing channel dynamic contact fatigue test can be met, and the subsequent repeated observation of crack generation and expansion causing channel fatigue damage can be conveniently realized through a certain detection method.

Description

Technical Field

[0001] The invention belongs to the field of rolling contact fatigue testing, and in particular relates to a bearing groove rolling contact fatigue testing device and a use method thereof. Background Art

[0002] Bearings are important components in the field of industrial machinery and are known as the "joints of equipment." With the advancement of industrial technology, the necessity of studying bearing fatigue failure has attracted much attention. As a key moving part in mechanical equipment, the performance of bearings directly affects the operating efficiency and safety of the equipment. During long-term operation, bearings will be subjected to repeated loads and friction, resulting in material fatigue, crack generation, and eventual failure. If the mechanisms of these fatigue failures are not studied in depth, it may lead to equipment failure, production stagnation, and even safety accidents. Therefore, in-depth research on the characteristics of bearing materials and their performance under working conditions, especially the generation and expansion of cracks, will help improve the durability and service life of traditional ball bearings. This has important engineering significance for improving the overall reliability and efficiency of industrial equipment.

[0003] For ball bearings, rolling contact fatigue failure is the most common failure mode. Rolling contact fatigue testing is also the main method for testing and evaluating bearing fatigue life. At present, although there are many rolling contact fatigue testing devices for ball bearings at home and abroad, there are certain shortcomings, mainly reflected in the following aspects: (1) Although the existing devices can test ball bearing fatigue damage, there are few special testing devices for bearing groove rolling contact fatigue. (2) When determining the location of ball bearing groove fatigue damage, the test bearing needs to be disassembled, which is too cumbersome. (3) Although the final location and extent of outer ring raceway damage can be determined by subsequent detection methods, it is not enough to observe the crack generation and expansion process that causes groove fatigue damage. Summary of the invention

[0004] The present invention provides a bearing groove rolling contact fatigue test device and a use method thereof, which can simulate the rolling contact fatigue state between the rolling element of a ball bearing and the bearing groove, meet the loading requirements of the ball bearing groove dynamic contact fatigue test, and facilitate the subsequent multiple observations of the generation and expansion of cracks causing groove fatigue damage through certain detection methods.

[0005] The technical solution of the present invention is as follows:

[0006] A bearing groove rolling contact fatigue test device comprises a frame, a power drive assembly, a loading assembly and a movable workbench assembly, wherein the power drive assembly, the loading assembly and the movable workbench assembly are arranged in the frame; a test piece is mounted on the movable workbench assembly, and the power drive assembly and the movable workbench assembly move in coordination so that the bearing groove of the test piece contacts with the rolling element of the loading assembly, and a rolling contact fatigue test is performed on the bearing groove through the rolling element.

[0007] Furthermore, the bearing groove rolling contact fatigue test device, the power drive assembly includes a motor 1, a screw 1, a nut 1, a screw connecting plate, a square support frame, a motor barrel, a motor 2, a baffle, a support rod and a transmission shaft gear system, the lower part of the frame is provided with a support plate, the upper end is provided with a top cover, two screws 1 are symmetrically arranged in the frame, the two ends of the screw 1 are rotatably connected to the support plate and the top cover respectively, two motors 1 are fixedly installed under the support plate and the output end of the motor 1 is fixedly connected to the lower end of the screw 1; a nut 1 is mounted on each screw 1, and the screw connecting plate is fixedly connected to the two nuts 1 together; the square support frame is fixedly installed on the lower end surface of the screw connecting plate, the tail of the motor barrel is fixedly installed in the square support frame, and the motor 2 is arranged in the motor barrel; the baffle is installed at the front of the motor barrel through a plurality of support rods, and the transmission shaft gear system is arranged between the baffle and the motor barrel.

[0008] Furthermore, in the bearing groove rolling contact fatigue test device, the transmission shaft gear system includes a central short shaft, a central wheel, an idler shaft, an idler, a sun shaft, a sun wheel, a synchronous pulley and a sleeve, three sleeves are fixedly arranged on the back of the baffle in a row and at equal intervals, an idler shaft is provided between two adjacent sleeves, two idler shafts are fixedly arranged on the back of the baffle, the central short shaft is rotatably connected to the sleeve located in the middle and axially positioned, and the two sun shafts are rotatably connected to the sleeves located on both sides and axially fixed; the central wheel is fixedly installed on the central short shaft, the idler is rotatably connected to the idler shaft and axially positioned, the sun wheel and the synchronous pulley are fixedly installed on the sun shaft, and the synchronous pulley is located in front of the baffle; the idler is meshed with the central wheel, and the sun wheel is meshed with the idler; one end of the central short shaft is fixedly connected to the output end of motor 2.

[0009] Furthermore, the bearing groove rolling contact fatigue testing device, the loading assembly includes a synchronous belt, rolling bodies and a pressing device, the synchronous belt is mounted on two synchronous pulleys; the synchronous belt is composed of a plurality of alloy plates connected in series, each alloy plate is provided with two rolling bodies, the rolling bodies protrude from the surface of the alloy plates; all rolling bodies are located at a position equidistant from one side of the synchronous belt; the pressing device is fixedly mounted on the front end face of the baffle.

[0010] Furthermore, in the bearing groove rolling contact fatigue test device, the pressing device includes a fixed clamp body, a movable clamp body, a pressing block, a second screw and a second nut. The fixed clamp body is fixedly mounted on the front end surface of the baffle, the second screw is rotationally connected to the fixed clamp body and axially positioned, the second nut is sleeved on the second screw, the movable clamp body is slidingly mounted with the fixed clamp body and fixedly connected with the second nut; the pressing block is fixedly mounted on the lower part of the movable clamp body, and the pressing block is opposite to the position of the rolling body; the second screw is powered by a pneumatic device.

[0011] Furthermore, the bearing groove rolling contact fatigue test device, the movable workbench assembly includes a base, a Y-direction guide rail, a lead screw three, a nut three, a workbench, a motor three and a clamp, the base is arranged on the support plate, two Y-direction guide rails are arranged in parallel on the base, the lead screw three is arranged between the two Y-direction guide rails, the nut three is mounted on the lead screw three, the workbench is slidably mounted together with the two Y-direction guide rails and is fixedly connected to the nut three; the motor three is fixedly mounted on the base, and the output end of the motor three is fixedly connected to one end of the lead screw three; the clamp is fixedly mounted on the workbench for clamping the test piece.

[0012] Furthermore, in the bearing groove rolling contact fatigue testing device, a pressure sensor is provided between the workbench and the Y-direction guide rail, and an acceleration sensor is installed next to the bearing groove of the specimen.

[0013] The method for using the bearing groove rolling contact fatigue test device comprises the following steps:

[0014] Step 1: Clamp the test piece on the fixture, start motor 1, make the rolling element on the synchronous belt contact the test piece, and turn off motor 1;

[0015] Step 2: Start the motor 3, drive the workbench and the fixture to move on the Y-direction guide rail through the lead screw 3, move the bearing groove of the test piece to just below the rolling body, and turn off the motor 3;

[0016] Step 3: Start the pneumatic device, and the second screw rotates to drive the pressing block to press the rolling element to contact the bearing groove of the test piece. When the contact load between the rolling element and the bearing groove of the test piece reaches a certain value, the load is maintained;

[0017] Step 4: Turn on motor 2, make the synchronous belt speed reach the preset test value, and start the bearing groove rolling contact fatigue test;

[0018] Step 5: During the test, an external data acquisition system is used to automatically collect the load signal transmitted by the pressure sensor, and to provide real-time feedback and control the action of the pneumatic device to ensure that the pressure between the bearing groove and the rolling element of the test piece is constant;

[0019] Step 6: During the test, the vibration signal transmitted by the acceleration sensor is automatically collected by the data acquisition control system; in the initial stage of the test, the vibration signal is usually relatively stable; when the vibration signal fluctuates greatly, it will be determined that cracks may appear in the bearing groove of the test piece. At this time, the test piece needs to be removed from the fixture, and the crack position on the test piece is inspected and observed and the data is recorded; after the observation, the test piece is reinstalled on the fixture and steps 1, 2, 3 and 4 are repeated to ensure that the contact fatigue test continues to run;

[0020] Step 7: In the test after the crack appears in the specimen, according to the change of the vibration signal fed back by the acceleration sensor, the test is stopped and the specimen is disassembled for multiple times, and the crack extension of the specimen is detected and the data is recorded; after each test, the specimen needs to be re-clamped and steps one, two, three and four are repeated.

[0021] Step 8: Compare the vibration signal value of the test piece with the preset value of the fatigue failure vibration signal; when the vibration signal value reaches or exceeds the preset value of the fatigue failure vibration signal, it is determined that fatigue failure has occurred in the test piece; the test ends.

[0022] The working principle of the present invention is as follows: the test piece is moved and contacted with the rolling body in the loading component by moving the workbench assembly; during the fatigue test, as the synchronous belt drives the loading component to rotate, the rolling contact between the rolling body in the loading component and the bearing groove of the test piece is realized, and the pressing device controls the pressing force through the pressure sensor, effectively simulating the contact state between the rolling body and the groove of the ball bearing; the external pressure sensor can measure the contact load between the loading component and the test piece in the fatigue test; when the fatigue test contact load deviates from the preset value, the contact load between the loading component and the test piece in the test is kept constant by controlling the pressing device; the external acceleration sensor is used to measure the vibration data of the test piece in the fatigue test; and the change of the vibration data during the test is used to determine when the crack appears in the test piece raceway and when it fails.

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

[0024] 1. The present invention can realize rolling contact between the rolling element and the groove of the test piece, and effectively simulate the contact effect between the rolling element and the groove when the ball bearing is working.

[0025] 2. Since the raceway on the test piece is only a part of the bearing raceway, there is no need to disassemble the bearing like existing equipment, which provides great convenience for determining the fatigue failure location and real-time detection of the generation and expansion of raceway cracks.

[0026] 3. The rolling contact fatigue test of ball bearing raceways of different types can be completed by simply replacing the loading components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of the bearing groove rolling contact fatigue test device;

[0028] Figure 2 This is the front view of the bearing groove rolling contact fatigue test device;

[0029] Figure 3 This is the left view of the bearing groove rolling contact fatigue test device;

[0030] Figure 4 It is a schematic diagram of the transmission shaft gear system;

[0031] Figure 5 Assembly diagram for the baffle, idler shaft and bushing;

[0032] Figure 6 is a schematic diagram of the alloy plate;

[0033] Figure 7 for Figure 6 Middle AA section view;

[0034] Figure 8 It is a schematic diagram of the pressing device;

[0035] Fig. 9 for Figure 8 Middle BB section view;

[0036] Fig.10 It is a schematic diagram of the motor barrel;

[0037] Fig.11 Schematic diagram of the test piece. DETAILED DESCRIPTION

[0038] like Figure 1-11 As shown, a bearing groove rolling contact fatigue test device includes a frame 1, a power drive assembly, a loading assembly and a movable workbench assembly, wherein the power drive assembly, the loading assembly and the movable workbench assembly are arranged in the frame 1; a test piece 18 is mounted on the movable workbench assembly, and the power drive assembly and the movable workbench assembly move in coordination so that a bearing groove 27 of the test piece 18 contacts a rolling element 20 of the loading assembly, and a rolling contact fatigue test is performed on the bearing groove 27 through the rolling element 20.

[0039] The power drive assembly includes a motor 13, a screw 17, a nut 18, a screw connecting plate 9, a square support frame 15, a motor barrel 16, a second motor, a baffle 12, a support rod and a transmission shaft gear system. The lower part of the frame 1 is provided with a support plate 5, and the upper end is provided with a top cover 6. Two screws 17 are symmetrically arranged in the frame 1, and the two ends of the screw 17 are rotatably connected to the support plate 5 and the top cover 6 respectively. Two motors 13 are fixedly installed under the support plate 5 and the output end of the motor 13 is fixedly connected to the lower end of the screw 17; a nut 18 is mounted on each screw 17, and the screw connecting plate 9 is fixedly connected to the two nuts 18 together; the square support frame 15 is fixedly installed on the lower end surface of the screw connecting plate 9, the tail of the motor barrel 16 is fixedly installed in the square support frame 15, and the second motor is arranged in the motor barrel 16; the baffle 12 is installed at the front of the motor barrel 16 through a plurality of support rods, and the transmission shaft gear system is arranged between the baffle 12 and the motor barrel 16. The transmission shaft gear system includes a central short shaft 21, a central wheel 22, an idler shaft 23, an idler 24, a sun shaft 11, a sun gear 25, a synchronous pulley 2 and a sleeve 26. Three sleeves 26 are fixedly arranged on the back of the baffle 12 in a row and at equal intervals. An idler shaft 23 is arranged between two adjacent sleeves 26. The two idler shafts 23 are fixedly arranged on the back of the baffle 12. The central short shaft 21 is rotatably connected to the sleeve 26 located in the middle and axially positioned. The two sun shafts 11 are rotatably connected to the sleeves 26 located on both sides and axially fixed; the central wheel 22 is fixedly installed on the central short shaft 21, the idler 24 is rotatably connected to the idler shaft 23 and axially positioned, the sun gear 25 and the synchronous pulley 2 are fixedly installed on the sun shaft 11, and the synchronous pulley 2 is located in front of the baffle 12; the idler 24 is meshed with the central wheel 22, and the sun gear 25 is meshed with the idler 24; one end of the central short shaft 21 is fixedly connected to the output end of the motor 2.

[0040] The loading assembly includes a synchronous belt 10, a rolling body 20 and a pressing device. The synchronous belt 10 is mounted on two synchronous pulleys 2. The synchronous belt 10 is composed of a plurality of alloy plates 19 connected in series. Each alloy plate 19 is provided with two rolling bodies 20, and the rolling bodies 20 protrude out of the surface of the alloy plate 19. All rolling bodies 20 are located at a position equidistant from one side of the synchronous belt 10. The pressing device is fixedly mounted on the front end face of the baffle 12. The pressing device includes a fixed clamp body 31, a movable clamp body 32, a pressing block 3, a second screw 33, and a second nut 34. The fixed clamp body 31 is fixedly installed on the front end surface of the baffle 12, the second screw 33 is rotatably connected to the fixed clamp body 31 and axially positioned, the second nut 34 is sleeved on the second screw 33, the movable clamp body 32 is slidably installed with the fixed clamp body 31 and fixedly connected with the second nut 34; the pressing block 3 is fixedly installed at the lower part of the movable clamp body 32, and the pressing block 3 is opposite to the position of the rolling body 20; the second screw 34 is powered by a pneumatic device.

[0041] The mobile workbench assembly includes a base, a Y-direction guide rail, a lead screw 3, a screw nut 3, a workbench 4, a motor 3 17 and a fixture 14. The base is arranged on the support plate 5, two Y-direction guide rails are arranged in parallel on the base, the lead screw 3 is arranged between the two Y-direction guide rails, the screw nut 3 is mounted on the lead screw 3, the workbench 4 is installed together with the two Y-direction guide rails in a sliding manner and is fixedly connected with the screw nut 3; the motor 3 17 is fixedly installed on the base, and the output end of the motor 3 17 is fixedly connected to one end of the screw 3; the fixture 14 is fixedly installed on the workbench 4 for clamping the test piece 18. A pressure sensor is arranged between the workbench 14 and the Y-direction guide rail, and the acceleration sensor is installed beside the bearing channel 27 of the test piece 18.

[0042] The method for using the bearing groove rolling contact fatigue test device comprises the following steps:

[0043] Step 1: Clamp the test piece 18 on the fixture 14, start the motor 13, so that the rolling element 20 on the synchronous belt 10 contacts the test piece 18, and turn off the motor 13;

[0044] Step 2: Start the motor 3 17, drive the workbench 4 and the fixture 14 to move on the Y-direction guide rail through the lead screw 3, move the bearing groove 27 of the test piece 18 to just below the rolling body 20, and turn off the motor 3 17;

[0045] Step 3: Start the pneumatic device, the screw 2 33 rotates to drive the pressing block 3 to press the rolling body 20 to contact the bearing groove 27 of the test piece 18, and when the contact load between the rolling body 20 and the bearing groove 27 of the test piece 18 reaches a certain value, the load is maintained;

[0046] Step 4: Turn on the motor 2, so that the speed of the synchronous belt 10 reaches the preset value of the test, and start the bearing groove rolling contact fatigue test;

[0047] Step 5: During the test, an external data acquisition system is used to automatically collect the load signal transmitted by the pressure sensor, and to provide real-time feedback and control the action of the pneumatic device to ensure that the pressure between the bearing groove 27 and the rolling element 20 of the test piece 18 is constant;

[0048] Step 6: During the test, the vibration signal transmitted by the acceleration sensor is automatically collected by using the data acquisition control system; in the initial stage of the test, the vibration signal is usually relatively stable; when the vibration signal fluctuates greatly, it will be determined that the bearing groove 27 of the test piece 18 may have cracks. At this time, the test piece 18 needs to be removed from the fixture 14, and the crack position on the test piece 18 is inspected and observed and the data is recorded; after the observation, the test piece 18 is reinstalled on the fixture 14 and steps 1, 2, 3 and 4 are repeated to ensure that the contact fatigue test continues to run;

[0049] Step 7: In the test after the crack appears in the specimen, according to the change of the vibration signal fed back by the acceleration sensor, the test is stopped several times and the specimen 18 is disassembled, and the crack extension of the specimen is detected and the data is recorded; after each test, the specimen 18 needs to be re-clamped and steps one, two, three and four are repeated.

[0050] Step eight: compare the vibration signal value of the test piece 18 during the test with the preset value of the fatigue failure vibration signal; when the vibration signal value reaches or exceeds the preset value of the fatigue failure vibration signal, it is determined that fatigue failure has occurred in the test piece 18; the test ends.

Claims

1. A bearing raceway rolling contact fatigue test device, characterized in that: The invention comprises a frame, a power drive assembly, a loading assembly and a mobile workbench assembly, wherein the power drive assembly, the loading assembly and the mobile workbench assembly are arranged in the frame; a test piece is mounted on the mobile workbench assembly, and the power drive assembly and the mobile workbench assembly move in coordination so that a bearing groove of the test piece contacts a rolling element of the loading assembly, and a rolling contact fatigue test is performed on the bearing groove through the rolling element.

2. The bearing raceway rolling contact fatigue testing device according to claim 1, characterized in that: The power drive assembly includes a motor 1, a lead screw 1, a nut 1, a lead screw connecting plate, a square support frame, a motor barrel, a second motor, a baffle, a support rod and a transmission shaft gear system. The lower part of the frame is provided with a support plate and the upper end is provided with a top cover. Two lead screws 1 are symmetrically arranged in the frame, and the two ends of the lead screw 1 are rotatably connected to the support plate and the top cover respectively. Two motors 1 are fixedly installed under the support plate and the output end of the motor 1 is fixedly connected to the lower end of the lead screw 1; a nut 1 is mounted on each lead screw 1, and the lead screw connecting plate is fixedly connected to the two nuts 1 together; the square support frame is fixedly installed on the lower end surface of the lead screw connecting plate, the tail of the motor barrel is fixedly installed in the square support frame, and the motor 2 is arranged in the motor barrel; the baffle is installed at the front of the motor barrel through a plurality of support rods, and the transmission shaft gear system is arranged between the baffle and the motor barrel.

3. The bearing raceway rolling contact fatigue testing device according to claim 2, characterized in that: The transmission shaft gear system includes a central short shaft, a central wheel, an idler shaft, an idler wheel, a sun shaft, a sun wheel, a synchronous pulley and a sleeve. Three sleeves are fixedly arranged on the back of the baffle in a row and at equal intervals. An idler shaft is provided between two adjacent sleeves. Two idler shafts are fixedly arranged on the back of the baffle. The central short shaft is rotatably connected to the sleeve in the middle and axially positioned. The two sun shafts are rotatably connected to the sleeves on both sides and axially fixed respectively; the central wheel is fixedly installed on the central short shaft, the idler wheel is rotatably connected to the idler shaft and axially positioned, the sun wheel and the synchronous pulley are fixedly installed on the sun shaft, and the synchronous pulley is located in front of the baffle; the idler wheel is meshed with the central wheel, and the sun wheel is meshed with the idler wheel; one end of the central short shaft is fixedly connected to the output end of motor 2.

4. The bearing raceway rolling contact fatigue testing device according to claim 3, characterized in that: The loading assembly includes a synchronous belt, a rolling body and a pressing device, wherein the synchronous belt is mounted on two synchronous pulleys; the synchronous belt is composed of a plurality of alloy plates connected in series, each alloy plate is provided with two rolling bodies, and the rolling bodies protrude out of the surface of the alloy plate; all the rolling bodies are located at a position equidistant from one side of the synchronous belt; the pressing device is fixedly mounted on the front end surface of the baffle.

5. The bearing raceway rolling contact fatigue testing device according to claim 4, characterized in that: The pressing device comprises a fixed clamp body, a movable clamp body, a pressing block, a second lead screw and a second nut. The fixed clamp body is fixedly mounted on the front end surface of the baffle, the second lead screw is rotationally connected to the fixed clamp body and axially positioned, the second nut is sleeved on the second lead screw, the movable clamp body is slidingly mounted with the fixed clamp body and fixedly connected with the second nut; the pressing block is fixedly mounted on the lower part of the movable clamp body, and the pressing block is opposite to the position of the rolling body; the second lead screw is powered by a pneumatic device.

6. The bearing raceway rolling contact fatigue testing device according to claim 2, characterized in that: The mobile workbench assembly includes a base, a Y-direction guide rail, a lead screw three, a nut three, a workbench, a motor three and a clamp, the base is arranged on the support plate, two Y-direction guide rails are arranged in parallel on the base, the lead screw three is arranged between the two Y-direction guide rails, the nut three is mounted on the lead screw three, the workbench is installed together with the two Y-direction guide rails in a sliding manner and is fixedly connected with the nut three; the motor three is fixedly installed on the base, and the output end of the motor three is fixedly connected to one end of the lead screw three; the clamp is fixedly installed on the workbench and is used to clamp the test piece.

7. The bearing raceway rolling contact fatigue testing device according to claim 6, characterized in that: A pressure sensor is arranged between the workbench and the Y-direction guide rail, and an acceleration sensor is installed beside the bearing channel of the test piece.

8. The method for using the bearing raceway rolling contact fatigue testing device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Clamp the test piece on the fixture, start motor 1, make the rolling element on the synchronous belt contact the test piece, and turn off motor 1; Step 2: Start the motor 3, drive the workbench and the fixture to move on the Y-direction guide rail through the lead screw 3, move the bearing groove of the test piece to just below the rolling body, and turn off the motor 3; Step 3: Start the pneumatic device, and the second screw rotates to drive the pressing block to press the rolling element to contact the bearing groove of the test piece. When the contact load between the rolling element and the bearing groove of the test piece reaches a certain value, the load is maintained; Step 4: Turn on motor 2, make the synchronous belt speed reach the preset test value, and start the bearing groove rolling contact fatigue test; Step 5: During the test, an external data acquisition system is used to automatically collect the load signal transmitted by the pressure sensor, and to provide real-time feedback and control the action of the pneumatic device to ensure that the pressure between the bearing groove and the rolling element of the test piece is constant; Step 6: During the test, the vibration signal transmitted by the acceleration sensor is automatically collected by the data acquisition control system; in the initial stage of the test, the vibration signal is usually relatively stable; when the vibration signal fluctuates greatly, it will be determined that cracks may appear in the bearing groove of the test piece. At this time, the test piece needs to be removed from the fixture, and the crack position on the test piece is inspected and observed and the data is recorded; after the observation, the test piece is reinstalled on the fixture and steps 1, 2, 3 and 4 are repeated to ensure that the contact fatigue test continues to run; Step 7: In the test after the crack appears in the specimen, according to the change of the vibration signal fed back by the acceleration sensor, the test is stopped and the specimen is disassembled for multiple times, and the crack extension of the specimen is detected and the data is recorded; after each test, the specimen needs to be re-clamped and steps one, two, three and four are repeated. Step 8: Compare the vibration signal value of the test piece with the preset value of the fatigue failure vibration signal; when the vibration signal value reaches or exceeds the preset value of the fatigue failure vibration signal, it is determined that fatigue failure has occurred in the test piece; the test ends.

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