Plate-shaped sample high-temperature fretting fatigue test equipment with controllable fretting slip amplitude

Abstract

The invention discloses high-temperature fretting fatigue test equipment for a plate-shaped sample. The high-temperature fretting fatigue test equipment comprises a cyclic load loading device, a normal load loading device, a heating device, a cooling device and a simply supported beam structure device. According to the high-temperature fretting fatigue test equipment for the plate-shaped sample, the test temperature is adjusted by controlling the output power of the heating device, and the influence of the heating device on the fatigue testing machine during heating is avoided by adopting the cooling device, so that a stable fretting fatigue test in a high-temperature environment is realized. Before the fretting fatigue test, the slip amplitude is adjusted according to the mechanics principle, and it is ensured that different slip amplitudes are obtained. Through the fretting pad formed by combining different line types and the replaceable and detachable fretting pad track, the same fretting pad can be used for multiple times, the influence of track abrasion after a fretting test is reduced through the replaceable and detachable fretting pad track, and the accuracy of a test result is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of material performance testing, and in particular relates to a high-temperature fretting fatigue testing device for a plate-shaped specimen with controllable fretting slip amplitude. Background Art

[0002] Fretting fatigue refers to the phenomenon that under cyclic loads, tiny relative sliding occurs when two components are in contact, resulting in a decrease in the fatigue life of the components. Under fretting conditions, the fatigue strength of components can be reduced to 2 / 3 of the normal fatigue strength or even lower. In aircraft structures, the problems of fretting fatigue failure and expensive maintenance costs have attracted widespread attention. Normally, the fretting fatigue life and fretting fatigue strength of components in high temperature environments will be reduced, which is believed to be due to the degradation of material properties caused by high temperature. High-temperature fretting fatigue is a complex phenomenon. In order to ensure the safety of turbofan engines, it is very important to study the fretting fatigue behavior of aero-engine titanium alloy blades and disks at operating temperatures. Therefore, the development of high-temperature fretting fatigue test equipment is crucial to explore the mechanism of high-temperature fretting fatigue.

[0003] A major problem faced by the current high-temperature fretting fatigue test equipment is the difficulty in changing and controlling the slip amplitude. The slip amplitude has a huge impact on the fretting fatigue life, but since the slip amplitude is at the micron level and needs to match the frequency of the spindle cyclic load, it is still difficult to implement high-temperature fretting fatigue tests with different slip amplitudes. Another major problem is that on the cross-type fretting fatigue device, the spacing between the two fretting pads is relatively small, resulting in a small design space, and the large design restrictions on the heating device make it difficult to add a heating device. Summary of the invention

[0004] In view of the above technical problems, the present invention aims to propose a high-temperature micro-motion fatigue test device for plate-shaped specimens with controllable micro-motion slip amplitude, wherein the combination of a heating device and a temperature control device can realize variable test temperature of high-temperature micro-motion fatigue test and can maintain a certain set temperature for a long time. The support plate forms a simply supported beam structure with the support platform through the slider, and the change of the slider position and the thickness of the support plate can realize the change of the micro-motion slip amplitude, so that the change of the slip amplitude can be controlled by theoretical calculation.

[0005] In order to achieve the above object, the present invention adopts the following technical solution.

[0006] The present invention provides a high temperature fretting fatigue test device for a plate-shaped specimen, 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.

[0007] Wherein, the cyclic load loading device comprises a first fatigue testing machine actuator and a second fatigue testing machine actuator;

[0008] The normal load loading device comprises a cylindrical linear variable combined micro-motion pad and a replaceable micro-motion pad track, wherein 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 component, a heat insulation component and a temperature monitoring component, and the temperature monitoring component is arranged in the temperature measuring hole;

[0010] The cooling device comprises an extended cooling rod and a cooling sensor, wherein the cooling sensor is provided with a cooling channel inside and a spring receiving portion on the upper part, a high-rigidity spring is received in the spring receiving portion, and a pressure sensor is also provided in the cooling sensor for measuring normal force; a cooling circuit is provided inside the extended cooling rod, the extended cooling rod is connected to the specimen through a pin shaft and transmits a cyclic load, the first fatigue testing machine actuator and the second fatigue testing machine actuator clamp the extended cooling rod, and the force is transmitted to the specimen through the pin shaft to provide a cyclic load in the vertical direction;

[0011] The heating temperature is monitored by a temperature monitoring component arranged in the temperature measuring hole of the cylindrical linear variable combined micro-motion pad; the heat exchange between the heating component and the outside is reduced by a heat insulation component, 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 fixed assembly, a support platform, a support plate, and a slider. The support platform is fixedly connected to the fixed assembly, the support plate and the slider are fixedly connected to the support platform, and the sample passes through the support plate and is fixed to the extended cooling rod.

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

[0014] Furthermore, the temperature monitoring component is a thermocouple.

[0015] Furthermore, the replaceable micro-motion pad track is tightly connected to the support plate via hammer-type bolts.

[0016] Furthermore, a T-shaped slot is provided in the support platform, and a corresponding slot structure is also provided in the support plate, and the sliding block is fixed to the support plate and the support platform by hammer-shaped bolts.

[0017] Furthermore, the replaceable micro-motion pad track and the cylindrical linear variable combined micro-motion pad adopt an interference fit to prevent the cylindrical linear variable combined micro-motion pad from moving.

[0018] Furthermore, the cylindrical linear variable combined micro-motion pad is designed as a hub type, and the matching part of the cylindrical linear variable combined micro-motion pad and the replaceable micro-motion pad track is set to a square or polygon, so that the cylindrical linear variable combined micro-motion pad can rotate and change its position.

[0019] Furthermore, a micro-motion pad and pressure sensor connecting piece is provided between the cylindrical linear variable combined micro-motion pad and the pressure sensor.

[0020] Furthermore, a spring and pressure sensor connector is provided between the high-rigidity spring and the pressure sensor, a force bolt is provided outside the high-rigidity spring, and a bolt and spring connector is provided between the high-rigidity spring and the force bolt.

[0021] The present invention also provides a method for temperature control using the high-temperature micromotion fatigue testing equipment for plate-shaped specimens with controllable micromotion slip amplitude. First, a preliminary test is performed to place the temperature monitoring component in the specimen and the temperature measuring hole, and the temperatures of the specimen and the cylindrical linear variable combined micromotion pad are compared at different temperatures, and fitting is performed to obtain the corresponding relationship between the temperature of the cylindrical linear variable combined micromotion pad and the temperature of the specimen. In the formal test, the temperature of the specimen is determined by the temperature of the cylindrical linear variable combined micromotion pad, thereby achieving control of the experimental environment temperature.

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

[0023] 1. Through the heating component, extended cooling rod, cooling sensor, and heat insulation component, the test temperature is monitored by a thermocouple fixed in the temperature measuring hole of the micro-motion pad. The structure is simple, small in space, highly versatile, and low in cost. In addition, cooling channels are provided in the extended cooling rod and the cooling sensor, so as to avoid the high temperature experimental environment affecting the operation of the test machine.

[0024] 2. When determining the strain of the specimen, the elastic modulus and thickness of the support plate, the distance between the slider and the support platform, and the friction between the cylindrical linear variable combined micro-motion pad and the specimen, the theoretical value of the slip amplitude can be estimated based on basic mechanical knowledge. Conversely, if the required slip amplitude is known, the thickness of the support plate and the position of the slider can be determined, thereby reducing the number and time of test adjustments.

[0025] 3. The measurement of the fretting fatigue slip amplitude is achieved by observing the sample and the fretting pad at the same time through industrial cameras and other ranging equipment. The difference in displacement between the sample and the fretting pad is analyzed through DIC technology to obtain the real-time slip amplitude.

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

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a structural front view of a high-temperature fretting fatigue testing device for a plate-shaped specimen with controllable fretting slip amplitude provided by an embodiment of the present invention.

[0029] Figure 2 It is a structural top view of a high-temperature fretting fatigue testing device for a plate-shaped specimen with controllable fretting slip amplitude provided in an embodiment of the present invention (the fatigue testing machine and the extended cooling rod are hidden).

[0030] Figure 3 It is a schematic diagram of a fretting pad container assembly of a high-temperature fretting fatigue testing device for a plate-shaped specimen with controllable fretting slip amplitude provided in an embodiment of the present invention.

[0031] Figure 4 It is a schematic diagram of a cooling sensor of a high-temperature fretting fatigue test device for a plate-shaped specimen with controllable fretting slip amplitude provided by an embodiment of the present invention.

[0032] Figure 5 It is a schematic diagram of a combination of cylindrical linear variable combined fretting pads of the same radius of a plate-shaped specimen high-temperature fretting fatigue test device with controllable fretting slip amplitude provided by an embodiment of the present invention.

[0033] Figure 6 It is a schematic diagram of different radius combinations of cylindrical linear variable combined fretting pads of a high-temperature fretting fatigue testing device for a plate-shaped specimen with controllable fretting slip amplitude provided by an embodiment of the present invention.

[0034] Figure 7 It is a schematic diagram of the positions of temperature measuring holes on a specimen and a cylindrical linear variable combined micromotion pad of a high-temperature micromotion fatigue test device for a plate-shaped specimen with controllable micromotion slip amplitude provided by an embodiment of the present invention.

[0035] Among them: 1-fixed component; 2-support platform; 3-support plate; 4-slider; 5-force bolt; 6-spring clamp; 7-cooling sensor; 8-cooling pipe; 9-first fatigue testing machine actuator; 10-second fatigue testing machine actuator; 11-extended cooling rod; 12-specimen; 13-heating component fixing seat; 14-thread plug; 15-high stiffness spring; 16-pressure sensor and spring connector; 17-replaceable micro-motion pad track; 18-heating device; 19-micro-motion pad and pressure sensor connector; 20-pressure sensor; 21-thermal insulation component; 22-cylindrical linear variable combined micro-motion pad; 23-bolt and spring connector; 24-fatigue testing machine column. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. The specific embodiments described here are only used to explain the present invention, and the present invention is not limited thereto.

[0037] Reference Figures 1 to 4 An embodiment of the present invention provides a high-temperature micro-motion fatigue test device for a plate-like specimen, which includes: 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 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 combined micro-motion pad 22 and a replaceable micro-motion pad track 17, wherein 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 includes a heating component 18, a heat insulation component 21 and a temperature monitoring component, wherein the temperature monitoring component is arranged in the temperature measuring hole, and preferably, the temperature monitoring component is a thermocouple. The cooling device includes an extended cooling rod 11 and a cooling sensor 7. The cooling sensor 7 is provided with a cooling channel inside and a spring accommodating portion on the upper part. A high-rigidity spring 15 is accommodated in the spring accommodating portion. The cooling sensor 7 is also provided with a pressure sensor 20 for measuring the normal force. A cooling circuit is provided inside the extended cooling rod 11. The extended cooling rod 11 is connected to the sample 12 through a pin shaft and transmits a 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 a cyclic load in the vertical direction.

[0038] The heating temperature is monitored by a temperature monitoring component arranged in the temperature measuring hole of the cylindrical linear variable combined 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 combined micro-motion pad 22 and the sample is kept stable;

[0039] The simply supported beam structure device includes a fixing component 1, a supporting platform 2, a supporting plate 3, and a sliding block 4. The supporting platform 2 is fixed to the fixing component 1, the supporting plate 3 and the sliding block 4 are fixedly connected to the supporting platform 2, and the sample 12 passes through the supporting plate 3 and is fixed to the extended cooling rod 11.

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

[0041] Two T-slots are provided in the support platform 2, and the hammer bolts can move in the T-slots. The support plate 3 also has a corresponding slot structure, and the support platform 2, the slider 4 and the support plate 3 are fixed by hammer bolts. According to the knowledge of mechanics: by changing the distance of the slider 4 from the center, the thickness of the support plate 3 and the elastic modulus, the deformation size of the contact between the support plate 3 and the replaceable micro-motion pad track 17 can be changed. By setting support plates 3 of different thicknesses for mutual combination and changing the distance of the slider 4 from the center, different sliding amplitudes can be achieved. For this purpose, three support plates 3 with thicknesses of 4 mm, 6 mm and 8 mm are set for mutual combination. The support platform 2 is engraved with scale values ​​to determine the position of the slider 4 in each test, 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 by a thermocouple placed in the small hole of the cylindrical linear variable combined micro-motion pad 22. The heat insulation assembly 21 reduces the heat exchange between the heating device and the outside world, and maintains the temperature stability of the cylindrical linear variable combined micro-motion pad 22 and the sample 12. The temperature stability during the test is controlled by the temperature control device to control the power of the heating device so that the test environment temperature remains stable.

[0043] The cooling water in the cooling sensor 7 is used to remove the heat of the sample during heating to prevent the temperature during the test from being transferred to the test machine and affecting the operation of the test machine. The extended cooling rod 11 can also reduce the influence of the heat transferred by the heated sample 12 on the actuator of the test machine through the internal cooling circuit.

[0044] The replaceable micro-motion pad track 17 and the cylindrical linear variable combined micro-motion pad 22 adopt interference fit to prevent the micro-motion pad from moving. Figure 5 and 6As shown, the cylindrical linear variable combined micro-motion pad 22 is designed as a hub type, and the matching part of the micro-motion pad and the track is set to a square or polygon, so that the cylindrical linear variable combined micro-motion pad 22 can be rotated to change its position. After each test, the wheel hub is rotated to make the unworn part of the cylindrical linear variable combined micro-motion pad 22 contact the sample, so that one micro-motion pad can be subjected to 4 or more micro-motion fatigue tests. In addition, the cylindrical linear variable combined micro-motion pad can be formed of different cylindrical surfaces, and the variable type of micro-motion pad is conducive to the exploration of micro-motion fatigue mechanism. The design of the replaceable micro-motion pad track can prevent the wear of the micro-motion pad track from affecting the size of the slip amplitude during the fatigue test.

[0045] A pressure sensor 20 is provided in the cooling sensor 7 for measuring the normal force. In order to accurately measure the normal force of the cylindrical linear variable combined micro-motion pad 22 and better fix the cylindrical linear variable combined micro-motion pad 22, a micro-motion pad and pressure sensor connector 19 is arranged between the cylindrical linear variable combined micro-motion pad 22 and the pressure sensor 20. A force bolt 5 is provided outside the high-rigidity spring 15, and a bolt and spring connector 23 is provided between the high-rigidity spring 15 and the force bolt 5. The force bolt 5 is provided in the spring clamp 6, and the application of the normal force is to push the bolt and spring connector 23 to compress the high-rigidity spring 15 by tightening the force bolt 5, and then apply the normal force through the high-rigidity spring. Applying the normal force through the high-rigidity spring can make the micro-motion pad 22 and the sample 12 still close together after wear, and keep the normal force basically unchanged.

[0046] The high-rigidity spring 15 is loaded via the force bolt 5 in the spring clamp 6. Tightening the force bolt 5 can increase the normal load. In order to make the loading of the high-rigidity spring 15 more stable, the high-rigidity spring 15 is connected to the force bolt 5 in the spring clamp 6 via a circular spring and bolt connector 8. In order to make the spring force measured by the pressure sensor 20 more accurate, a spring and pressure sensor connector 16 is provided between the spring 15 and the pressure sensor 20.

[0047] The lower end of the support platform 2 adopts a reinforcing rib design to enhance the support stability, while the left end adopts an arc-shaped structure to fix the support platform. The radius of the arc-shaped structure is the same as that of the cylinder, and the arc is 170 degrees. The radius and arc of the fixing component 1 are the same as those of the support platform 2. Since the arcs of the support platform 2 and the fixing component 1 are both 170 degrees, a certain gap will be formed between the two and the cylinder, which is conducive to the bolts to firmly fix the support platform on the cylinder.

[0048] The left and right support platforms 2 are each provided with two positioning holes. The left and right support platforms can use positioning round bars 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 positioning round bars on the support platform 2 can also prevent the support platforms at both ends from deviating during the test.

[0049] The measurement of the fretting fatigue slip amplitude is carried out by observing the sample and the fretting pad at the same time through industrial cameras and other ranging equipment, and the real-time slip amplitude is obtained by analyzing the difference in displacement between the sample and the fretting pad through DIC technology.

[0050] Measuring the temperature of the contact surface in an actual fretting test is not a simple task. The main reason for this is that the fretting pad contact area is blocked. Moreover, welding or connecting any device (e.g. thermocouple) may turn itself into a stress concentration source and change the stress state of the evaluated fretting situation. In order to perform the proposed high-temperature fretting fatigue test, an indirect temperature measurement technique was used in this work. Preliminary tests were conducted to establish an equation that relates the temperature of the contact area and the control point. For this purpose, three shallow holes were drilled in the TC11 specimen to measure the temperature in and near the area where the contact occurs, and holes were drilled in the fretting pad to place the control thermocouples, such as Figure 7 The temperature control method is to first conduct a preliminary test to place the thermocouple in the temperature measuring holes on the sample and the micro-motion pad, compare the temperature of the sample and the micro-motion pad at different temperatures, and fit the corresponding relationship between the micro-motion pad temperature and the sample temperature. In the formal test, the sample temperature is determined by the temperature of the micro-motion pad to achieve the control of the experimental environment temperature.

[0051] Embodiment 1:

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

[0053] The test material is determined to be a plate specimen made of 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 1334N, the amplitude of the cyclic load of the spindle is 800MPa, and the stress cycle ratio is 0.1. The friction coefficient between the micro-motion pad and the specimen is 0.45.

[0054]

[0055] like Figure 1As shown, first build the fixing assembly 1 and the support platform 2, and use a laser level to confirm that the left and right support platforms are on the same plane. At the same time, keep the left and right support planes aligned, so as to ensure the centering of the two micro-motion pads. Connect the slider 4 and the support plate 3 with hammer bolts. The sample 12 is fixed to the extended cooling rod 11 through a pin, and the sample is passed through the support plate 3 and adjusted to a suitable position. The extended cooling rod is clamped by the upper and lower hydraulic test machine actuators 9 and 10. Then assemble the micro-motion pads, etc. Figure 3 The micro-motion pad container shown is then fixed to the support plate and the micro-motion pad is in contact with the sample. The heating assembly 18 is installed on the support plate through the heating assembly fixing seat 13, and the thermocouple is fixed in the temperature measuring hole of the micro-motion pad. After the heating device and the control device are connected, the force bolt 5 is tightened to push the bolt and the spring connector 23 to compress the high-rigidity spring 15, and then the normal force is applied through the high-rigidity spring 15 to observe the value of the pressure sensor 20 to the set value 1334N and then stop. Start the cooling device and the heating device, set the required ambient temperature on the control device to turn on the device, observe the real-time temperature change on the control device, and when the temperature stabilizes to the set value, start the fatigue testing machine to perform the micro-motion fatigue test.

[0056] The measurement of the fretting fatigue slip amplitude is carried out by observing the sample and the fretting pad at the same time through an industrial camera, and the difference in displacement between the sample and the fretting pad is analyzed by DIC technology to obtain the real-time slip amplitude.

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

[0058]

[0059] Where W max is the maximum deflection of the support plate 3 after the force is applied; 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, and 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 used for the support plate 3; I is the section 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 movement 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 combined micro-motion pad 22 follows the movement of the sample 12, and the smaller the relative movement, thereby reducing the slip amplitude.

[0060] Embodiment 2:

[0061] In order to verify the feasibility and beneficial effects of this method, this example discloses a fretting fatigue life test device for testing materials at different slip amplitudes, and 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 parts and assemble the heating device on the micro-motion device. Then, place the thermocouples in the holes of the specimen and micro-motion pad. Next, set the temperature on the controller. When the specimen (15 mm long area, Figure 7 ) and the temperature measured by the fretting pad remain constant, increase the set temperature of the controller. Then, repeat the previous step until the measured temperature on the specimen is above the temperature required for the fretting fatigue test (540°C). It must be noted that the measured temperatures may vary significantly if the heating device and thermocouples are not installed in the exact position in all tests. Following the test method just described, tests were performed. In each test, all temperatures were recorded and their results were averaged into the results reported in Table 1. Finally, a quadratic regression fit was used, and the function that relates the fretting pad temperature to the average temperature measured on the specimen was defined 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 micromotion pad point. The expected temperature error in the specimen temperature estimate is ±10°C.

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

[0066]

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

[0068] (1) Heat the fretting pad and the specimen to the required test temperature using a heating device and temperature monitoring and control equipment;

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

[0070] (3) Through the micro-motion pads that can be composed of different linear combinations and the replaceable micro-motion pad tracks, the same micro-motion pad can be used multiple times, and the replaceable micro-motion pad tracks can reduce the impact of track wear after micro-motion tests, ensuring the accuracy of test results. In addition, the special micro-motion pad design connects thermocouples to monitor the temperature of the sample during the test;

[0071] (4) Use a cooling device with cooling pipes to prevent the high temperature during the test from being transferred to the testing machine and affecting its operation.

[0072] Compared with the expensive customized dual-axis drive test equipment used abroad, the device of the present invention has obvious cost advantages. In addition, it is understood that there are almost no authorized patents for plate-shaped specimen fretting fatigue devices in China, and there is no method to measure the fretting fatigue life of materials under different slip amplitudes under high temperature test conditions on a conventional fatigue testing machine. Therefore, the present invention fills the technical gap in the field of fretting fatigue testing in China and provides a reliable, accurate and economical solution for measuring the fretting fatigue life of materials.

[0073] It should be noted that the above-described embodiments are only preferred embodiments of the present invention. For those skilled in the art, without departing from the principles of the present invention, the present invention may be modified, improved and replaced with equivalents, and these modifications, improvements and equivalent replacements are also considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A high temperature fretting fatigue test equipment for plate-shaped specimens, characterized in that: include: A cyclic load loading device, a normal load loading device, a heating device, a cooling device and a simply supported beam structure 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), wherein 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 component (18), a heat insulation component (21), and a temperature monitoring component, wherein the temperature monitoring component is arranged in the temperature measuring hole; The cooling device comprises an extended cooling rod (11) and a cooling sensor (7), wherein the cooling sensor (7) is provided with a cooling channel inside and a spring receiving portion on the top, wherein a high-rigidity spring (15) is received in the spring receiving portion, and the cooling sensor (7) is also provided with a pressure sensor (20) for measuring normal force; a cooling circuit is provided inside the extended cooling rod (11), the extended cooling rod (11) is connected to a specimen (12) via a pin shaft and transmits a cyclic load, the first fatigue testing machine actuator (9) and the second fatigue testing machine actuator (10) clamp the extended cooling rod (11), and force is transmitted to the specimen (12) via the pin shaft to provide a cyclic load in a vertical direction; The heating temperature is monitored by a temperature monitoring component arranged in a temperature measuring hole of the cylindrical linear variable combined 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 combined micro-motion pad (22) and the sample (12) remains stable; The simply supported beam structure device comprises a fixing assembly (1), a supporting platform (2), a supporting plate (3), and a sliding block (4); the supporting platform (2) is fixedly connected to the fixing assembly (1); the supporting plate (3) and the sliding block (4) are fixedly connected to the supporting platform (2); and the sample (12) passes through the supporting plate (3) and is fixed to the extended cooling rod (11).

2. The high temperature fretting fatigue test equipment for plate-shaped specimens according to claim 1, characterized in that: The heating component (18) is fixed on the support plate (3) via a heating component fixing seat (13).

3. The high temperature fretting fatigue test equipment for plate-shaped specimens according to claim 1, characterized in that: The temperature monitoring component is a thermocouple.

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

5. The high temperature fretting fatigue test equipment for plate-shaped specimens according to claim 1, characterized in that: The support platform (2) is provided with a T-shaped slot, and the support plate (3) is also provided with a corresponding slot structure. The sliding block (4) is fixed to the support plate (3) and the support platform (2) by means of hammer bolts.

6. The high temperature fretting fatigue test equipment for plate-shaped specimens according to claim 1, characterized in that: The replaceable micro-motion pad track (17) and the cylindrical linear variable combined micro-motion pad (22) are in interference fit, so as to prevent the cylindrical linear variable combined micro-motion pad (22) from moving.

7. The high temperature fretting fatigue test equipment for plate-shaped specimens according to claim 1, characterized in that: The cylindrical linear variable combined micro-motion pad (22) is designed as a hub type, and the matching part of the cylindrical linear variable combined micro-motion pad (22) and the replaceable micro-motion pad track (17) is arranged in a square or polygonal shape, so that the cylindrical linear variable combined micro-motion pad (22) can rotate to change its position.

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

9. The plate-shaped specimen high temperature fretting fatigue test equipment with controllable fretting slip amplitude according to claim 1 is characterized in that: A spring and pressure sensor connector (16) is provided between the high-rigidity spring (15) and the pressure sensor (20), a force bolt (5) is provided outside the high-rigidity spring (15), and a bolt and spring connector (23) is provided between the high-rigidity spring (15) and the force bolt (5).

10. A method for temperature control using the high-temperature micromotion fatigue testing equipment for plate-shaped specimens with controllable micromotion slip amplitude according to claim 1, comprising: firstly conducting a preliminary test to place the temperature monitoring component in the specimen and the temperature measuring hole, comparing the temperatures of the specimen and the cylindrical linear variable combined micromotion pad at different temperatures, and performing fitting to obtain the corresponding relationship between the temperature of the cylindrical linear variable combined micromotion pad and the temperature of the specimen, thereby determining the specimen temperature through the temperature of the cylindrical linear variable combined micromotion pad during the formal test to achieve control of the experimental environment temperature.

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