A high-temperature fretting fatigue test device for a plate-shaped sample with controllable amplitude of microslip

Abstract

The application discloses a high-temperature fretting fatigue test equipment for a plate-shaped sample, which comprises a cyclic load loading device, a normal load loading device, a heating device, a cooling device and a simply supported beam structure device. The high-temperature fretting fatigue test equipment for the plate-shaped sample adjusts a test temperature by controlling the output power of the heating device, avoids the influence of the heating device on a fatigue testing machine when heating by using the cooling device, and thus realizes stable fretting fatigue experiments under a high-temperature environment. Before the fretting fatigue test, the slip amplitude is adjusted according to the mechanical principle, so that different slip amplitudes can be obtained. The fretting pad which can be combined by different line types and the replaceable fretting pad track are used, so that the same fretting pad can be used for multiple times, the influence of track abrasion after the fretting test is reduced through the replaceable fretting pad track, and the accuracy of the test result is ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material performance testing, and particularly relates to a high-temperature fretting fatigue test device for a plate-shaped sample with controllable fretting amplitude. BACKGROUND

[0002] Fretting fatigue refers to a phenomenon that the fatigue life of components is reduced due to the micro relative sliding between two components under cyclic loading. Under the condition of fretting, the fatigue strength of components can be reduced to 2 / 3 of the ordinary fatigue strength or even lower. In aircraft structures, fretting fatigue failure and high maintenance costs have attracted widespread attention. Generally, the fretting fatigue life and the fretting fatigue strength of components under high temperature environment are reduced, which is considered to be caused by the degradation of material performance due to high temperature. High-temperature fretting fatigue is a complex phenomenon, and it is very important to study the fretting fatigue behavior of turbine engine titanium alloy blades and discs at working temperature to ensure the safety of the turbine engine. Therefore, the development of high-temperature fretting fatigue test equipment is crucial to the exploration of high-temperature fretting fatigue mechanism.

[0003] The current high-temperature fretting fatigue test equipment faces a major problem that the change and control of the sliding amplitude are difficult. The sliding amplitude has a great influence on the fretting fatigue life, but since the sliding amplitude is in the micron level and needs to be matched with the frequency of the main shaft cyclic loading, it is still difficult to realize high-temperature fretting fatigue test with different sliding amplitudes. Another major problem is that the space for design is small due to the small distance between the two fretting pads on the cross-type fretting fatigue device, and it is difficult to add heating equipment due to the design limitation of the heating device. SUMMARY

[0004] In view of the above technical problems, the present application aims to provide a high-temperature fretting fatigue test device for a plate-shaped sample with controllable fretting amplitude, wherein the combination of the heating device and the temperature control device can realize variable test temperature and long-time maintenance of a certain set temperature for high-temperature fretting fatigue test. The support plate forms a simply supported beam structure with the support platform through the sliding block, and the change of the sliding block position and the thickness of the support plate can realize the change of the fretting sliding amplitude, so that the change amount of the sliding amplitude can be controlled through theoretical calculation.

[0005] In order to achieve the above purpose, the present application adopts the following technical solutions.

[0006] The present application provides a high-temperature fretting fatigue test device for a plate-shaped sample, which comprises a cyclic loading loading device, a normal load loading device, a heating device, a cooling device and a simply supported beam structure device,

[0007] The cyclic loading loading device comprises a first fatigue test machine actuator and a second fatigue test machine actuator.

[0008] The normal load loading device comprises a cylindrical linear variable combined micro-motion pad, a replaceable micro-motion pad track, the cylindrical linear variable combined micro-motion pad is arranged in the replaceable micro-motion pad track, and a temperature measuring hole is arranged on the cylindrical linear variable combined micro-motion pad.

[0009] The heating device comprises a heating assembly, a heat insulation assembly and a temperature monitoring assembly, and the temperature monitoring assembly is arranged in the temperature measuring hole.

[0010] The cooling device comprises an elongated cooling rod and a cooling sensor, the cooling sensor is internally provided with a cooling channel and is provided with a spring accommodating portion at the upper portion, a large-stiffness spring is accommodated in the spring accommodating portion, and a pressure sensor is further arranged in the cooling sensor to measure the normal force; the elongated cooling rod is internally provided with a cooling loop, the elongated cooling rod is connected to the sample through a pin shaft and transmits the cyclic load, the first fatigue testing machine actuator and the second fatigue testing machine actuator clamp the elongated cooling rod, and the force is transmitted to the sample through the pin shaft to provide the cyclic load in the vertical direction.

[0011] The temperature monitoring assembly arranged in the temperature measuring hole of the cylindrical linear variable combined micro-motion pad is used for monitoring the heating temperature; the heat insulation assembly is used for reducing the heat exchange between the heating assembly and the outside, so that the temperature of the cylindrical linear variable combined micro-motion pad and the sample is kept stable.

[0012] The simply supported beam structure device comprises a fixing assembly, a support platform, a support plate and a sliding block, the support platform is fixedly connected to the fixing assembly, the support plate and the sliding block are fixedly connected to the support platform, and the sample is fixed to the elongated cooling rod through the support plate.

[0013] Further, the heating assembly is fixed on the support plate through a heating assembly fixing seat.

[0014] Further, the temperature monitoring assembly is a thermocouple.

[0015] Further, the replaceable micro-motion pad track and the support plate are tightly connected through hammer-type bolts.

[0016] Further, the support platform is provided with a T-shaped groove, the support plate is also provided with a corresponding groove structure, and the sliding block is fixed with the support plate and the support platform through hammer-type bolts.

[0017] Further, the replaceable micro-motion pad track and the cylindrical linear variable combined micro-motion pad adopt an interference fit, which is used for preventing the cylindrical linear variable combined micro-motion pad from moving.

[0018] Further, the cylindrical linear variable combined micro-motion pad is designed as a hub type, and the cylindrical linear variable combined micro-motion pad and the replaceable micro-motion pad track matching part are arranged as a square or polygon, so that the cylindrical linear variable combined micro-motion pad can be rotated to replace positions.

[0019] Further, the micro-motion pad and pressure sensor connector is arranged between the cylindrical linear variable combined micro-motion pad and the pressure sensor.

[0020] Further, the spring and pressure sensor connector is arranged between the large stiffness spring and the pressure sensor, the large stiffness spring is externally provided with a force bolt, and the bolt and spring connector is arranged between the large stiffness spring and the force bolt.

[0021] The application also provides a temperature control method using the micro-motion slip amplitude controllable plate-shaped sample high-temperature micro-motion fatigue test equipment, first, the pre-test is performed to place the temperature monitoring assembly in the sample and the temperature measuring hole, the temperatures of the sample and the cylindrical linear variable combined micro-motion pad at different temperatures are compared and fitted to obtain the corresponding relationship between the temperature of the cylindrical linear variable combined micro-motion pad and the temperature of the sample, so that the sample temperature is determined by the temperature of the cylindrical linear variable combined micro-motion pad during the formal test, and the control of the experimental environment temperature is realized.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] 1. The test temperature is monitored by the thermocouple fixed in the temperature measuring hole of the micro-motion pad through the heating assembly, the extended cooling rod, the cooling type sensor and the heat insulation assembly. The structure is simple, the occupied space volume is small, the universality is strong, and the cost is low. The cooling channel is arranged in the extended cooling rod and the cooling type sensor, so that the operation of the testing machine can be avoided in the high-temperature experimental environment.

[0024] 2. When the strain of the sample, the elastic modulus and the thickness of the support plate, the distance of the slider at both ends of the support platform and the friction between the cylindrical linear variable combined micro-motion pad and the sample are determined, the theoretical value of the slip amplitude can be estimated according to the basic mechanical knowledge. On the contrary, if the required slip amplitude is known, the thickness of the support plate and the position of the slider can be determined, so that the number of test adjustments and the time are reduced.

[0025] 3. The measurement of the micro-motion fatigue slip amplitude simultaneously observes the sample and the micro-motion pad through the industrial camera and other ranging devices, and obtains the real-time slip amplitude size through the DIC technology to analyze the displacement size difference between the sample and the micro-motion pad.

[0026] 4. The device is used for high-temperature micro-motion fatigue test on a conventional fatigue testing machine, and the device combination is relatively simple and the experimental cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only aim to some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0028] Figure 1 is a structural front view of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0029] Figure 2 is a structural plan view of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application (hides the fatigue test machine and the extended cooling rod).

[0030] Figure 3 is a schematic diagram of the fretting pad container assembly of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0031] Figure 4 is a schematic diagram of the cooling sensor of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0032] Figure 5 is a schematic diagram of the same radius combination of the cylindrical linear variable combination fretting pad of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0033] Figure 6 is a schematic diagram of the different radius combination of the cylindrical linear variable combination fretting pad of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0034] Figure 7 is a schematic diagram of the temperature measurement hole position on the sample and the cylindrical linear variable combination fretting pad of the high-temperature fretting fatigue test equipment for a plate-shaped sample with controllable fretting slip amplitude provided by the embodiment of the present application.

[0035] Wherein: 1-fixed assembly; 2-support platform; 3-support plate; 4-sliding block; 5-tight bolt; 6-spring clamp; 7-cooled sensor; 8-cooling pipeline; 9-first fatigue testing machine actuator; 10-second fatigue testing machine actuator; 11-extended cooling rod; 12-sample; 13-heating assembly fixing seat; 14-tap; 15-high stiffness spring; 16-pressure sensor and spring connecting piece; 17-replaceable micro-motion pad track; 18-heating device; 19-micro-motion pad and pressure sensor connecting piece; 20-pressure sensor; 21-heat insulation assembly; 22-cylindrical linear variable combined micro-motion pad; 23-bolt and spring connecting piece; 24-fatigue testing machine column. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with examples and the accompanying drawings of the specification. The specific examples described herein are only used to explain the present application, and the present application is not limited thereto.

[0037] Reference Figures 1 to 4 The embodiment of the present application provides a high-temperature micro-motion fatigue test equipment for a plate-shaped sample, which comprises a cyclic load loading device, a normal load loading device, a heating device, a cooling device and a micro-motion measuring device, wherein the cyclic load loading device comprises a first fatigue testing machine actuator 9 and a second fatigue testing machine actuator 10; the normal load loading device comprises a cylindrical linear variable combined micro-motion pad 22 and a replaceable micro-motion pad track 17, the cylindrical linear variable combined micro-motion pad 22 is arranged in the replaceable micro-motion pad track 17, and a temperature measuring hole is arranged on the cylindrical linear variable combined micro-motion pad 22; the heating device comprises a heating assembly 18, a heat insulation assembly 21 and a temperature monitoring assembly, the temperature monitoring assembly is arranged in the temperature measuring hole, and preferably, the temperature monitoring assembly is a thermocouple. The cooling device comprises an extended cooling rod 11 and a cooled sensor 7, the inside of the cooled sensor 7 is provided with a cooling channel, the upper part of the cooled sensor 7 is provided with a spring accommodating portion, a high stiffness spring 15 is accommodated in the spring accommodating portion, and a pressure sensor 20 is further arranged in the cooled sensor 7 to measure the normal force; the inside of the extended cooling rod 11 is provided with a cooling loop, the extended cooling rod 11 is connected with the sample 12 through a pin shaft and transmits the cyclic load, the first fatigue testing machine actuator 9 and the second fatigue testing machine actuator 10 clamp the extended cooling rod 11, and the force is transmitted to the sample 12 through the pin shaft to provide the cyclic load in the vertical direction.

[0038] The temperature monitoring assembly arranged in the temperature measuring hole of the cylindrical linear variable combined micro-motion pad 22 monitors the heating temperature; the heat insulation assembly 21 reduces the heat exchange between the heating assembly 18 and the outside world, so that the temperature of the cylindrical linear variable combined micro-motion pad 22 and the sample is kept stable.

[0039] The simple beam structure device comprises a fixing assembly 1, a support platform 2, a support plate 3, and a sliding block 4, the support platform 2 is fixed to the fixing assembly 1, the support plate 3 and the sliding block 4 are fixedly connected to the support platform 2, and the sample 12 is fixed to the extended cooling rod 11 through the support plate 3.

[0040] The replaceable fretting pad track 17 is tightly connected to the support plate 3 through a hammer bolt. During the fretting fatigue test, the cylindrical linear variable combined fretting pad 22 has the same movement trend as the sample 12 due to the existence of friction, so the cylindrical linear variable combined fretting pad 22 gives the support plate 3 a certain pressure through the replaceable fretting pad track 17, the deformation amount of the support plate 3 changes the relative sliding between the cylindrical linear variable combined fretting pad 22 and the sample 12, and the deformation amount of the support plate is changed by changing the position of the sliding block 4 on the support platform 2, so as to change the relative sliding distance between the cylindrical linear variable combined fretting pad 22 and the sample 12.

[0041] The support platform 2 is provided with two T-shaped grooves, the hammer bolt can move in the T-shaped grooves, the support plate 3 also has a corresponding groove structure, and the support platform 2, the sliding block 4 and the support plate 3 are fixed through the hammer bolt. According to the knowledge of mechanics, the deformation size at the contact position of the support plate 3 and the replaceable fretting pad track 17 can be changed by changing the distance of the sliding block 4 from the center, the thickness of the support plate 3 and the elastic modulus. Different sliding amplitude values can be realized by setting support plates 3 with different thicknesses and changing the distance of the sliding block 4 from the center. Three support plates 3 with thicknesses of 4 mm, 6 mm and 8 mm are combined with each other. The support platform 2 is marked with a scale value for determining the position of the sliding block 4 each time, so as to achieve the purpose of controlling the sliding amplitude.

[0042] The heating assembly 18 is fixed on the support plate 3 through the heating assembly fixing seat 13, and the heating temperature is monitored through the thermocouple placed in the small hole of the cylindrical linear variable combined fretting pad 22. The heat exchange between the heating device and the outside is reduced through the heat insulation assembly 21, so as to maintain the stability of the temperature at the cylindrical linear variable combined fretting pad 22 and the sample 12. The stable temperature during the test is controlled by the temperature control device to control the power of the heating device, so as to maintain the stability of the test environment temperature.

[0043] The cooling water in the pipeline in the cooling sensor 7 is used to take away the heat of the sample during heating, so as to avoid the temperature during the test from being transmitted to the testing machine and affecting the operation of the testing machine. The extended cooling rod 11 can also reduce the influence of the heat transmitted by the sample 12 during heating on the actuator of the testing machine through the internal cooling circuit.

[0044] The replaceable fretting pad track 17 and the cylindrical linear variable combined fretting pad 22 adopt an interference fit to prevent the fretting pad from moving. Figure 5 and 6As shown, the cylindrical linear variable combined fretting pad 22 is designed as a hub, and the fretting pad and track matching part is designed as a square or polygon, so that the cylindrical linear variable combined fretting pad 22 can be rotated to change position, and the hub is rotated after each test, so that the part of the cylindrical linear variable combined fretting pad 22 that is not worn is in contact with the sample, and the same fretting pad can be used for four or more fretting fatigue tests. The cylindrical linear variable combined fretting pad can be composed of different cylindrical surfaces, and the type of the fretting pad can be changed to facilitate the exploration of the fretting fatigue mechanism. The design of the replaceable fretting pad track can avoid the influence of the wear of the fretting pad track on the slip amplitude during the fatigue test.

[0045] A pressure sensor 20 is arranged in the cooling sensor 7 to measure the normal force. In order to accurately measure the normal force of the cylindrical linear variable combined fretting pad 22 and better fix the cylindrical linear variable combined fretting pad 22, a fretting pad and pressure sensor connecting piece 19 is arranged between the cylindrical linear variable combined fretting pad 22 and the pressure sensor 20. A force bolt 5 is arranged outside the high-stiffness spring 15, and a bolt and spring connecting piece 23 is arranged between the high-stiffness spring 15 and the force bolt 5. The force bolt 5 is arranged in the spring clamping piece 6, and the application of the normal force is achieved by tightening the force bolt 5 to push the bolt and spring connecting piece 23 to compress the high-stiffness spring 15, and then the normal force is applied by the high-stiffness spring. The application of the normal force by the high-stiffness spring can make the fretting pad 22 and the sample 12 still adhere to each other after wear, and the normal force remains basically unchanged.

[0046] The loading of the high-stiffness spring 15 is loaded by the force bolt 5 in the spring clamping piece 6, and tightening the force bolt 5 can increase the normal load. In order to make the loading of the high-stiffness spring 15 more stable, the high-stiffness spring 15 and the force bolt 5 in the spring clamping piece 6 are connected by a circular spring and bolt connecting piece 8. In order to make the spring force measured by the pressure sensor 20 more accurate, a spring and pressure sensor connecting piece 16 is arranged between the spring 15 and the pressure sensor 20.

[0047] The lower end of the support platform 2 is designed with reinforcing ribs to enhance the stability of the support, and the left end is designed with a circular arc structure for fixing the support platform. The radius of the circular arc structure is the same as that of the cylinder, and the arc is 170 degrees. The radius and arc of the fixing assembly 1 are the same as those of the support platform 2. Since the arcs of the support platform 2 and the fixing assembly 1 are both 170 degrees, a certain gap is formed between them and the cylinder, which is conducive to the firm fixation of the support platform on the cylinder by the bolts.

[0048] The support platform 2 at the left and right ends is provided with two positioning holes. The support platform at the left and right ends can use a positioning round bar to pass through the two positioning holes to ensure that the platforms at the left and right ends are consistent in height and aligned in direction after assembly. The positioning holes and the positioning round bar on the support platform 2 can also prevent the support platforms at the left and right ends from being deviated during the test.

[0049] The measurement of the microslip amplitude is achieved by using a distance measuring device such as an industrial camera to observe the specimen and the fretting pad simultaneously. The real-time slip amplitude is obtained by analyzing the displacement difference between the specimen and the fretting pad through the DIC technology.

[0050] It is not a simple task to measure the temperature of the contact surface in the actual fretting test. The main reason for this is that the contact area of the fretting pad is blocked. In addition, welding or connecting any device (such as a thermocouple) can itself become a stress concentration source and change the stress state of the fretting condition being evaluated. In order to carry out the proposed high-temperature fretting fatigue test, an indirect temperature measurement technique is used in this work. Preliminary tests are carried out to establish an equation relating the temperature of the contact area and the control point. For this purpose, three shallow holes are drilled in the TC11 specimen to measure the temperature of the contact area and its vicinity, and a hole is drilled in the fretting pad to place a control thermocouple, as shown in Figure 7 The temperature control method is to first carry out a pre-test by placing the thermocouple in the temperature measuring hole above the specimen and the fretting pad, comparing the temperature of the specimen and the fretting pad at different temperatures, and fitting to obtain the corresponding relationship between the temperature of the fretting pad and the temperature of the specimen, so as to determine the temperature of the specimen by the temperature of the fretting pad during the formal test, thereby realizing the control of the temperature of the experimental environment.

[0051] Example 1

[0052] In order to verify the feasibility and beneficial effects of the method, the embodiment discloses a fretting fatigue life test device for testing the fretting fatigue life of a plate-shaped specimen under different slip amplitudes, and the specific steps are as follows:

[0053] The test material is determined to be a plate-shaped specimen prepared from a heat-treated TC11 alloy. The material parameters of the TC11 alloy are listed in detail in Table 1. The normal load of the test is 1334 N, the amplitude of the cyclic load of the main shaft is 800 MPa, and the stress cycle ratio is 0.1. The friction coefficient between the fretting pad and the specimen is 0.45.

[0054]

[0055] As Figure 1As shown, first build fixed components 1 and support platform 2, through the laser level to confirm the left and right sides of the support platform in the same plane at the same time to keep the left and right two support plane left-right alignment, so as to ensure the centering of the two micro-motion pads. The slider 4 and the support plate 3 are connected by the hammer type bolt. The sample 12 is fixed to the extended cooling rod 11 by the pin shaft, the sample is passed through the support plate 3 and adjusted to the appropriate position, and the extended cooling rod is clamped by the upper and lower hydraulic test machine actuators 9, 10. Then the micro-motion pad is assembled as Figure 3 The micro-motion pad container is fixed to the support plate as shown and the micro-motion pad is in contact with the sample. The heating assembly 18 is installed on the support plate by the heating assembly fixing seat 13, and the thermocouple is fixed in the temperature measuring hole of the micro-motion pad. After connecting the heating device with the control device, tighten the force bolt 5, push the bolt and spring connector 23 to compress the large stiffness spring 15, then observe the value of the pressure sensor 20 to the set value 1334N through the large stiffness spring 15, and stop. Start the cooling device and the heating device, set the required environmental temperature on the control device, start the device, and observe the real-time temperature change on the control device. When the temperature is stable to the set value, start the fatigue testing machine to conduct the fretting fatigue test.

[0056] The measurement of the fretting fatigue slip amplitude is to observe the sample and the micro-motion pad at the same time through the industrial camera, and to obtain the real-time slip amplitude size by analyzing the displacement size difference between the sample and the micro-motion pad through the DIC technology.

[0057] In order to adjust the slip amplitude: if it is necessary to reduce the slip amplitude, the slider 4 can be moved to the maximum distance from the center, and a cyclic load is applied. The camera is used to detect the slip amplitude, which can be reduced to 25μm. To further reduce the slip amplitude, the thickness of the support plate 3 can be reduced to 10μm. If it is necessary to increase the slip amplitude, the distance of the slider 5 from the center should be reduced or the thickness of the support plate 3 should be increased. The method of adjusting the thickness of the support plate 3 and the distance of the slider 4 can refer to the deflection calculation formula of the simply supported beam.

[0058]

[0059] In the formula, W max is the maximum deflection of the support plate 3 after being stressed; F is the pressure of the micro-motion pad 22 on the support plate 3, which is approximately equal to the product of the normal pressure and the friction coefficient, which is 600N in this embodiment; a is the distance between the slider 4 and the position of the force, i.e. the position of the sample surface; E is the elastic modulus of the material of the support plate 3; I is the cross-sectional moment of inertia of the support plate 3; and L is the distance between the two sliders 4. Since the slip amplitude is caused by the relative motion of the micro-motion pad 14 and the sample 4, the greater the deflection of the support plate 3, the greater the distance that the cylindrical linear variable combination type micro-motion pad 22 follows the motion of the sample 12, and the smaller the relative motion, thereby resulting in a decrease in the slip amplitude.

[0060] Example 2:

[0061] To verify the feasibility and beneficial effects of the present method, the present example discloses a device for testing the fretting fatigue life of a material at different slip amplitudes, the specific steps are as follows:

[0062] The method used to obtain the equation relating the temperature at the contact to the temperature at the control point is as follows: first, align the contact components and assemble the heating device on the fretting device. Then, place the thermocouples in the holes of the specimen and the fretting pad. Next, set the temperature on the controller. When the temperature measured by the specimen (15 mm long region, Figure 7 ) and the fretting pad remains constant, increase the set temperature of the controller. Then, repeat the previous step until the measured temperature on the specimen is higher than the temperature required for the fretting fatigue test (540℃). It must be noted that if the heating device and thermocouples are not installed in the exact position in all tests, the measured temperature can vary significantly. According to the test method just described, tests were carried out. In each test, all temperatures were recorded and their results were averaged into the results reported in Table 1. Finally, using a quadratic regression fit, the function was defined that relates the fretting pad temperature to the average temperature measured on the specimen as:

[0063] g(T c ) = -0.002T c 2 + 1.55T c - 9.1407

[0064] Where g(Tc) estimates the average temperature at the specimen as a function of the temperature Tc measured at the point of the fretting pad. The estimated temperature error in the specimen temperature is ±10℃.

[0065] Table 1. Temperatures measured in the temperature calibration test

[0066]

[0067] It can be seen that the fretting slip amplitude controllable plate-shaped specimen high-temperature fretting fatigue test device of the present application solves the following technical problems:

[0068] (1) The fretting pad and the specimen are heated to the required test temperature by the heating device and the temperature monitoring control device;

[0069] (2) Before the fretting fatigue test, the slip amplitude is adjusted according to the principle of mechanics to ensure that different slip amplitudes are obtained;

[0070] (3) Through the micro-motion pad which can be combined by different lines and the replaceable micro-motion pad track, the same micro-motion pad can be used for multiple times, and the influence of track wear after micro-motion test is reduced through the replaceable micro-motion pad track, so that the accuracy of test results is ensured. In addition, the thermocouple is connected through special micro-motion pad design, so that the temperature condition during sample test is monitored;

[0071] (4) Through the cooling device with a cooling pipeline, the high temperature in the test is avoided from being transmitted to the testing machine to affect the operation of the testing machine.

[0072] Compared with the expensive custom dual-shaft driving test equipment used abroad, the device has obvious cost advantage. In addition, it is understood that there is almost no authorized patent of the plate-shaped sample micro-motion fatigue device in China at present, and there is no method for measuring the micro-motion fatigue life of materials under different slip amplitude conditions under high temperature test conditions on a conventional fatigue testing machine. Therefore, the present application fills the technical blank in the field of micro-motion fatigue test in China, and provides a reliable, accurate and economic solution for the measurement of material micro-motion fatigue life.

[0073] It should be pointed out that the above-described embodiments are only preferred embodiments of the present application. For ordinary skilled in the art, some modifications, improvements and equivalent replacements can be made to the present application without departing from the principles of the present application, and these modifications, improvements and equivalent replacements are also considered to fall within the protection scope of the claims of the present application.

Claims

1. A high-temperature fretting fatigue testing device for plate-shaped specimens with controllable fretting slip amplitude, characterized in that, include: Cyclic load loading device, normal load loading device, heating device, cooling device, and simply supported beam structure device, among which, The cyclic load loading device includes a first fatigue testing machine actuator (9) and a second fatigue testing machine actuator (10); The normal load loading device includes a cylindrical linear variable combination micro-motion pad (22) and a replaceable micro-motion pad track (17). The cylindrical linear variable combination micro-motion pad (22) is disposed in the replaceable micro-motion pad track (17). A temperature measuring hole is provided on the cylindrical linear variable combination micro-motion pad (22). The heating device includes a heating component (18), a heat insulation component (21), and a temperature monitoring component, wherein the temperature monitoring component is disposed in the temperature measuring hole; The cooling device includes an extended cooling rod (11) and a cooling sensor (7). The cooling sensor (7) has a cooling channel inside and a spring housing at the top. A high-stiffness spring (15) is housed in the spring housing. The cooling sensor (7) also has a pressure sensor (20) for measuring the normal force. The extended cooling rod (11) has a cooling circuit inside. The extended cooling rod (11) is connected to the specimen (12) through a pin and transmits the cyclic load. The first fatigue testing machine actuator (9) and the second fatigue testing machine actuator (10) clamp the extended cooling rod (11). The force is transmitted to the specimen (12) through the pin to provide a vertical cyclic load. The heating temperature is monitored by a temperature monitoring component arranged in the temperature measuring hole of the cylindrical linear variable combination micro-motion pad (22); the heat exchange between the heating component (18) and the outside is reduced by the heat insulation component (21) so that the temperature of the cylindrical linear variable combination micro-motion pad (22) and the sample (12) remains stable. The simply supported beam structure device includes a fixing component (1), a support platform (2), a support plate (3), and a slider (4). The support platform (2) is fixedly connected to the fixing component (1), the support plate (3) and the slider (4) are fixedly connected to the support platform (2), and the sample (12) passes through the support plate (3) and is fixed to the extended cooling rod (11).

2. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The heating component (18) is fixed on the support plate (3) by the heating component fixing seat (13).

3. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The temperature monitoring component is a thermocouple.

4. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The replaceable micro-motion pad track (17) is tightly connected to the support plate (3) by hammer bolts.

5. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The support platform (2) is provided with a T-shaped groove, and the support plate (3) is also provided with a corresponding groove structure. The slider (4) is fixed to the support plate (3) and the support platform (2) by hammer bolts.

6. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The replaceable micro-motion pad track (17) and the cylindrical linear variable combination micro-motion pad (22) are interference-fitted to prevent the cylindrical linear variable combination micro-motion pad (22) from moving.

7. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, The cylindrical linear variable combination micro-motion pad (22) is designed as a hub shape. The mating part between the cylindrical linear variable combination micro-motion pad (22) and the replaceable micro-motion pad track (17) is set as a square or polygon, so that the cylindrical linear variable combination micro-motion pad (22) can be rotated to change position.

8. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, A connecting piece (19) for the micro-motion pad and the pressure sensor is provided between the cylindrical linear variable combination micro-motion pad (22) and the pressure sensor (20).

9. The high-temperature fretting fatigue testing equipment for plate-shaped specimens with controllable fretting slip amplitude according to claim 1, characterized in that, A pressure sensor and spring connector (16) is provided between the high stiffness spring (15) and the pressure sensor (20). A force-applying bolt (5) is provided on the outside of the high stiffness spring (15). A bolt and spring connector (23) is provided between the high stiffness spring (15) and the force-applying bolt (5).

10. A method for temperature control using a high-temperature fretting fatigue testing device for plate-shaped specimens with controllable fretting slip amplitude as described in claim 1, comprising: firstly, conducting a pre-test by placing the temperature monitoring component in the specimen and the temperature measuring hole; comparing the temperatures of the specimen and the cylindrical linear variable combination fretting pad at different temperatures and fitting the results to obtain the correspondence between the temperature of the cylindrical linear variable combination fretting pad and the temperature of the specimen; thereby determining the specimen temperature through the temperature of the cylindrical linear variable combination fretting pad during the formal test, thus achieving control of the experimental environment temperature.

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