Hot-static pressure-vibration combined loading fatigue S-N curve testing device and method

Abstract

The invention belongs to the field of multi-field coupling tests, and particularly relates to a hot-static pressure-vibration combined loading fatigue S-N curve testing device and method. During a test, the vibration table provides vibration load excitation, the high-temperature accelerometer on the pressing block picks up the vibration load, and the vibration load is fed back to the vibration controller to realize vibration closed-loop control; the vacuum pump provides a negative pressure load, the negative pressure load is picked up through the pressure transmitter mounted on the air chamber, and the negative pressure load is fed back to the pressure controller to realize negative pressure closed-loop control; the quartz lamp heater provides a thermal load, and the surface temperature of the test piece is measured through the thermocouple installed at the root of the test piece and is fed back to the thermal controller to realize closed-loop control of the surface temperature of the test piece. And finally, hot-static pressure-vibration combined loading and accurate control are realized. According to the invention, hot, static and vibration loads can be loaded at the same time, and a hot-static pressure-vibration combined fatigue S-N curve loading test can be carried out on materials / structural elements of weak acoustic fatigue parts of civil aircrafts.

Description

Technical Field

[0001] The present application belongs to the field of multi-field coupling tests, and in particular relates to a thermal-static pressure-vibration combined loading fatigue SN curve testing device and method. Background Art

[0002] The wing lift enhancement devices and engine acoustic linings of civil aircraft are the areas with serious noise loads, and most of them adopt the form of composite panel honeycomb sandwich structure. For civil aircraft with engine wing mounting, the flap structure is located within the range of the engine jet. Since the engine jet will generate strong noise loads and high temperature environment, when the aircraft takes off and lands, the lift enhancement device is opened, and the flaps are directly affected by the jet and aerodynamic forces. Constrained structures in high temperature environments will produce large compressive stresses due to thermal expansion of materials. The cumulative effect of aerodynamic heating will also cause the temperature distribution of the aircraft structure to change over time, thereby causing changes in the structural modal frequency and vibration type. The flexible deformation of the structure will also cause the aircraft to have additional angles of attack, etc., causing additional aerodynamic uncertainty. Thermal stress will cause local instability of the structure. Under the combined action of strong noise loads, it will cause the structure to have a jump response, resulting in significant damage to the structure.

[0003] In order to better study the local fatigue life of civil aircraft under such a complex load environment, it is necessary to use the fatigue SN curve of local materials / structures as test data support. In the existing fatigue life analysis, the thermal-static pressure-vibration coupled environment life analysis mostly uses the vibration fatigue SN curve data as the main basis for its life analysis. However, the general vibration fatigue SN curve data does not consider the influence of the temperature environment on the fatigue performance of the material, and does not reflect the influence of the local average stress caused by the static pressure load on the fatigue characteristics of the material. Therefore, there is a problem of large errors in the life analysis results.

[0004] Existing testing technologies cannot effectively cover the SN curve test of fatigue under combined heat-static pressure-vibration loading of components. The identification method and device disclosed in the invention "Method and device for identifying SN characteristics of material vibration based on structural vibration test (publication number: CN118278225A)" only apply to pure vibration loads and cannot include high temperature environments and static pressure loads. The test method disclosed in the invention "A test method for vibration fatigue performance of pipeline structures (publication number: CN115979561A)" also only applies to pure vibration loads and cannot be adapted to situations involving high temperature environments and static pressure loads. At present, no device or method for realizing the SN curve test of combined heat-static pressure-vibration loading has been found in similar SN curve test patents.

[0005] In summary, the heat-static pressure-vibration combined loading fatigue SN curve test method and test device can effectively cover the material / structure fatigue SN curve test of fatigue damage parts of civil aircraft, and are significantly different from the traditional material vibration SN test method and device.

[0006] The static pressure loading method (external force method) with the bearing foundation located outside the test fixture has a more obvious systematic error when conducting static pressure-vibration or static pressure-vibration combined tests. There are many static pressure loading methods in general two-field coupling environments, including air chamber loading, hydraulic actuation loading in high temperature environments, etc. However, in a complex three-field coupling environment, there are many restrictions on static pressure loading. Conventional methods such as adhesive tape cannot be used because they cannot adapt to high temperature environments, which greatly increases the difficulty of static pressure loading. Therefore, the design of the static pressure loading device should fully consider the adverse effects of high temperature environments on the static pressure loading device itself.

[0007] Stress and strain measurement in high temperature environment is different from that in normal temperature environment. The thermal output error of the strain gauge caused by temperature needs to be considered. The lateral effect caused by thermal expansion needs to be considered. Therefore, it is necessary to reasonably eliminate the system error in the stress and strain measurement link.

[0008] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0009] The purpose of the present application is to provide a thermal-static pressure-vibration combined loading fatigue SN curve testing device and method to solve at least one problem existing in the prior art.

[0010] The technical solution of this application is:

[0011] A thermal-static-vibration combined loading fatigue SN curve testing device, comprising:

[0012] A vibration table, the vibration table having a vibration part and a static part, the vibration part is located at the center of the static part;

[0013] An air chamber, wherein the air chamber is connected to a vacuum pump through an air pipe, an upper opening is formed at an upper end of the air chamber, a lower opening is formed at a lower end of the air chamber, the air chamber is arranged on a stationary part of the vibration table, a rubber sealing pad is arranged between the air chamber and the stationary part of the vibration table, and an opening at a lower end of the air chamber corresponds to a vibration part of the vibration table;

[0014] A cover plate, the cover plate being mounted on the upper opening of the gas chamber, and a quartz glass plate being arranged on the cover plate;

[0015] A fixture, wherein the fixture is fixedly mounted on the vibration part of the vibration table;

[0016] A test piece, wherein the test piece is mounted on the fixture and is located in a closed cavity formed by the air chamber, the cover plate, the vibration table and the rubber sealing pad, and a medium-temperature strain gauge is installed on the test piece;

[0017] A quartz lamp heater is installed on the quartz glass plate, and infrared radiation light from the quartz lamp heater passes through the quartz glass plate and irradiates onto the test piece in the sealed cavity.

[0018] In at least one embodiment of the present application, a plurality of quartz glass windows are provided on the side wall of the gas chamber.

[0019] In at least one embodiment of the present application, a pressure transmitter is installed on the air chamber, and the pressure transmitter is connected to a pressure controller, and the vacuum pump is closed-loop controlled by the pressure controller.

[0020] In at least one embodiment of the present application, a water cooling pipe is installed on the cover plate, and the water cooling pipe has a cooling water joint.

[0021] In at least one embodiment of the present application, a handle is installed on the cover plate.

[0022] In at least one embodiment of the present application, the fixture includes a base and a support platform, wherein:

[0023] The base is fixedly mounted on the vibrating part of the vibrating table;

[0024] The support platform is arranged on the base, and the test piece is pressed onto the support platform by a pressing block and fixed with bolts.

[0025] In at least one embodiment of the present application, a high-temperature accelerometer is attached to the pressing block, and the high-temperature accelerometer is connected to a vibration controller, and the vibration table is closed-loop controlled by the vibration controller.

[0026] In at least one embodiment of the present application, a thermocouple is attached to the test piece, and the thermocouple is connected to a thermal controller, and the quartz lamp heater is closed-loop controlled by the thermal controller.

[0027] The second aspect of the present application provides a heat-static pressure-vibration combined loading fatigue SN curve test method, based on the heat-static pressure-vibration combined loading fatigue SN curve test device as described above, comprising:

[0028] Step 1: obtaining a first relative relationship between a strain response result of a test piece and a vibration load, and a second relative relationship between a strain response result of the test piece and a fatigue life through a vibration loading test;

[0029] Step 2: determining the vibration load frequency and multiple vibration load magnitudes of the heat-static pressure-vibration combined loading test according to the first relative relationship and the second relative relationship;

[0030] Step 3, respectively carry out heat-static pressure-vibration combined loading tests according to the determined vibration load frequency and different vibration load magnitudes, collect multiple sets of strain response results, and record the cumulative test time at the time of failure of the test piece, and calculate the number of fatigue cycles according to the vibration load frequency and the cumulative test time;

[0031] Step 4: According to the strain response results and the number of fatigue cycles, the least squares method is used to fit the thermal-static pressure-vibration combined loading fatigue SN curve of the test piece.

[0032] In at least one embodiment of the present application, in step 3, the number of fatigue cycles is calculated according to the vibration load frequency and the accumulated test time:

[0033] The number of fatigue cycles is:

[0034]

[0035] Where, t is the cumulative test time, f1 is the lower limit of the vibration load frequency, and f2 is the upper limit of the vibration load frequency.

[0036] The invention has at least the following beneficial technical effects:

[0037] The heat-static pressure-vibration combined loading fatigue SN curve testing device of the present application can load heat, static pressure, and vibration loads simultaneously, and can carry out heat-static pressure-vibration combined loading fatigue SN curve testing on materials / structural elements in weak parts of acoustic fatigue of civil aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an overall schematic diagram of a heat-static pressure-vibration combined loading fatigue SN curve test device according to one embodiment of the present application;

[0039] Figure 2 This is a schematic diagram of the interior of a heat-static pressure-vibration combined loading fatigue SN curve test device according to one embodiment of the present application;

[0040] Figure 3 is a schematic diagram of a cover plate according to an embodiment of the present application;

[0041] Figure 4 It is a flow chart of a heat-static pressure-vibration combined loading fatigue SN curve testing method according to one embodiment of the present application.

[0042] in:

[0043] 1- vacuum pump, 2- air pipe, 3- cover plate, 4- quartz lamp heater, 5- air chamber, 6- quartz glass window, 7- pressure transmitter, 8- vibration table, 9- test piece, 10- pressing block, 11- medium temperature strain gauge, 12- thermocouple, 13- fixture, 14- rubber sealing gasket, 15- cooling water joint, 16- handle, 17- quartz glass plate, 18- water cooling pipe. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0045] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0046] The following is combined with Figures 1 to 4 This application is described in further detail.

[0047] A first aspect of the present application provides a heat-static pressure-vibration combined loading fatigue SN curve testing device, comprising: a vibration table 8, an air chamber 5, a cover plate 3, a fixture 13, a test piece 9 and a quartz lamp heater 4.

[0048] like Figure 1-2As shown, the vibration table 8 is used to load the test piece with a vibration load. The vibration table 8 has a vibration part and a static part, and the vibration part is located at the center of the static part. The air chamber 5 is arranged on the vibration table 8. The air chamber 5 is connected to the vacuum pump 1 through the air pipe 2. The vacuum pump 1 is used to provide negative pressure conditions for the air chamber 5. The upper end of the air chamber 5 is provided with an upper opening, and the lower end is provided with a lower opening. The air chamber 5 is arranged on the static part of the vibration table 8. A rubber sealing gasket 14 is arranged between the air chamber 5 and the static part of the vibration table 8. The rubber sealing gasket 14 is specially used to block the gap between the vibration table 8 and the air chamber 5 to ensure the air tightness of the air chamber 5. The opening at the lower end of the air chamber 5 corresponds to the vibration part of the vibration table 8. It is preferred that a plurality of quartz glass windows 6 are arranged on the side wall of the air chamber 5, for example, 4 quartz glass windows 6 are designed on the air chamber 5, so as to realize the state of the test piece 9 to be observed at any time during the test. A pressure transmitter 7 is installed on the air chamber 5, and the pressure transmitter 7 is connected to the pressure controller. The pressure transmitter 7 is used to monitor the internal pressure value of the air chamber 5 and feed it back to the pressure controller. The pressure controller performs closed-loop control on the start and stop of the vacuum pump 1 to control the air pressure inside the air chamber 5.

[0049] The cover plate 3 is installed on the upper opening of the air chamber 5, and can seal the upper opening of the air chamber 5. A quartz glass plate 17 is inlaid in the center of the cover plate 3, so that the radiation capacity of the quartz lamp heater 4 can pass through the glass directly to the surface of the test piece 9. In the preferred embodiment of the present application, a water cooling pipe 18 is installed on the cover plate 3, and the water cooling pipe 18 has a cooling water joint 15. Cooling water is passed into the water cooling pipe 18 through the cooling water joint 15, so that the cover plate 3 will not be deformed due to overheating, resulting in the loss of air tightness of the air chamber 5. Advantageously, in this embodiment, two handles 16 are also installed on the cover plate 3 to facilitate daily installation and use.

[0050] The fixture 13 is fixedly mounted on the vibration part of the vibration table 8. The test piece 9 is mounted on the fixture 13, and the test piece 9 is located in a closed cavity formed by the air chamber 5, the cover plate 3, the vibration table 8 and the rubber sealing pad 14. The closed cavity formed by the air chamber 5, the cover plate 3, the vibration table 8 and the rubber sealing pad 14 can achieve a special pressure condition of wrapping different from the atmospheric pressure outside the test piece 9 through the vacuum pump 1. A medium-temperature strain gauge 11 is installed at the root of the test piece 9 to monitor the strain response and frequency change of the test piece 9. A special medium-temperature strain gauge 11 is used to tightly bond it to the test piece 9 by spot welding. The wire is led out to a lower temperature position using a high-temperature resistant cable, and then welded to an ordinary cable and connected to a strain collector.

[0051] In the preferred embodiment of the present application, the fixture 13 includes a base and a support platform, wherein the base is fixedly mounted on the vibration part of the vibration platform 8; the support platform is arranged on the base and is integrally formed with the base, and the test piece 9 is pressed onto the support platform by the pressing block 10 and fixed with bolts to realize the boundary fixation of the test piece 9. It is understandable that the support platform needs to have an appropriate height so that the tip of the test piece 9 will not collide with the wall of the air chamber 5 during the vibration loading process.

[0052] In the preferred embodiment of the present application, a high-temperature accelerometer is attached to the pressing block 10 as a test vibration control point. The high-temperature accelerometer should be able to withstand a high-temperature load not lower than the surface temperature of the test piece 9. The high-temperature accelerometer is connected to a vibration controller, and the vibration table 8 is closed-loop controlled by the vibration controller. A thermocouple 12 is attached to the root of the test piece 9 to monitor the surface temperature of the test piece 9. The thermocouple 12 is connected to a thermal controller, and the quartz lamp heater 4 is closed-loop controlled by the thermal controller.

[0053] The quartz lamp heater 4 is mounted on the quartz glass plate 17 , and the infrared radiation light of the quartz lamp heater 4 passes through the quartz glass plate 17 and irradiates the surface of the test piece 9 in the closed cavity, thereby heating the test piece 9 .

[0054] The heat-static pressure-vibration combined loading fatigue SN curve test device of the present application is designed with specific parameters according to the test piece size and load conditions. The thermal load, static pressure load, and vibration load are all controlled in a closed loop during loading to achieve precise control, and each load is loaded independently without mutual interference.

[0055] The heat-static pressure-vibration combined loading fatigue SN curve test device of the present application, during the test, the vibration table 8 provides vibration load excitation, the high temperature accelerometer on the pressure block 10 picks up the vibration load size, and feeds back to the vibration controller to realize vibration closed-loop control; the vacuum pump 1 provides negative pressure load, draws air in the closed air chamber 5 through the air pipe 2, picks up the negative pressure load size through the pressure transmitter 7 installed on the air chamber 5, and feeds back to the pressure controller to realize negative pressure closed-loop control; the quartz lamp heater 4 provides heat load, and the surface temperature of the test piece 9 is measured by the thermocouple 12 installed at the root of the test piece 9, and is fed back to the thermal controller to realize closed-loop control of the surface temperature of the test piece 9; finally, heat-static pressure-vibration combined loading and precise control are realized. During the test, the state of the test piece 9 can be observed at any time through the quartz glass window 6.

[0056] Based on the above-mentioned heat-static pressure-vibration combined loading fatigue SN curve test device, the second aspect of the present application provides a heat-static pressure-vibration combined loading fatigue SN curve test method, which is carried out in the order of preliminary test and formal test, and specifically includes the following steps:

[0057] Step 1: obtaining a first relative relationship between a strain response result of a test piece and a vibration load, and a second relative relationship between a strain response result of the test piece and a fatigue life through a vibration loading test;

[0058] Step 2: determining the vibration load frequency and multiple vibration load magnitudes of the heat-static pressure-vibration combined loading test according to the first relative relationship and the second relative relationship;

[0059] Step 3, respectively carry out heat-static pressure-vibration combined loading tests according to the determined vibration load frequency and different vibration load magnitudes, collect multiple sets of strain response results, and record the cumulative test time at the time of failure of the test piece, and calculate the number of fatigue cycles according to the vibration load frequency and the cumulative test time;

[0060] Step 4: According to the strain response results and the number of fatigue cycles, the least squares method is used to fit the thermal-static pressure-vibration combined loading fatigue SN curve of the test piece.

[0061] In a specific implementation of the present application, the main implementation process of the test is as follows:

[0062] 1) First, conduct a preliminary test. The preliminary test is carried out in the following steps.

[0063] 2) Measure the first-order resonance frequency of the test piece. Install two test pieces on the fixture, apply low-level broadband vibration load, and obtain the strain response peak frequency of the test piece, which is used as the first-order resonance frequency of the test piece;

[0064] 3) Determine the upper and lower limits of the narrowband frequency of vibration loading. The upper and lower limits of the narrowband frequency of the formal test are set to the frequency range corresponding to a 6dB drop in the peak value of the strain response frequency domain of the test piece;

[0065] 4) Measure the strain linear response range of the test piece. Take a test piece and load 8 orders of magnitude of narrow-band random vibration loads with equal order intervals, and measure the strain response values ​​corresponding to each load level. Perform a linear fit with the vibration load level as the horizontal axis and the strain response result as the vertical axis to obtain the linear relationship range between the strain response result and the vibration load level;

[0066] 5) Determine the failure position of the test piece. Take 2 test pieces to carry out fatigue failure tests. Select a certain vibration load for fatigue testing and record the strain response size and fatigue life of the test piece. On the one hand, observe the failure position of the test piece, and on the other hand, explore the relationship between the response level and life;

[0067] 6) Determine the excitation levels of each group in the formal test. The formal test load is divided into five excitation levels from high to low: A, B, C, D, and E. Based on the relationship between the dynamic stress and the excitation level measured in the preliminary test, and the relationship between the stress level and the life of the two test pieces obtained in step 5), a comprehensive analysis is performed to determine the test level of group B, which is the second highest level group. Then determine the vibration levels of the other groups in the following order:

[0068] [1] The test level of Group D is determined based on the test results of Group B (Group D is the second lowest level group);

[0069] [2] The test results of Group B and Group D were used to fit the SN curve, and the test magnitude of Group C was determined based on the curve;

[0070] [3] The SN curve is fitted using the test results of groups B, C, and D, and the test magnitude of group A is determined based on the curve;

[0071] [4] The SN curve was fitted using the test results of four groups, A, B, C, and D, and the test magnitude of group E was determined based on the curve.

[0072] 7) Next, conduct the formal test. The main contents of the formal test are: joint loading of heat, static pressure, and vibration loads. Keep the surface temperature of the test piece constant, the static pressure inside the air chamber constant, adjust the vibration load, and conduct each group of tests in the order of B, D, C, A, and C;

[0073] 8) For composite panel honeycomb sandwich test pieces, when the response peak frequency changes by more than 10%, the test piece is considered to be damaged. During the formal test, if the strain response peak frequency of a test piece changes by more than 10%, the test piece is considered to be damaged. The cumulative test time at the time of test piece damage is recorded, and the number of fatigue cycles at the time of test piece damage is calculated according to the formula. Remove the test piece, install a counterweight of the same mass as the test piece, and continue the test until all test pieces in the group are damaged;

[0074] The calculation formula for the number of fatigue cycles N is:

[0075]

[0076] Wherein, t is the cumulative test time, f1 is the lower limit frequency of the narrow band, and f2 is the upper limit frequency of the narrow band.

[0077] 9) The corresponding root mean square stress response result is calculated according to the root mean square strain response measurement result of each test piece, and then combined with the life measurement result of each test piece, the least squares method is used to fit the thermal-static pressure-vibration combined loading fatigue SN curve of the test piece.

[0078] The heat-static pressure-vibration combined loading fatigue SN curve test method of the present application utilizes a vibration table to load and simulate the response of a structure under a noise load, and then uses the vibration SN curve of the test piece to replace the acoustic fatigue SN curve; a narrow-band random vibration load is loaded with the peak frequency of the strain response of the test piece as the center, and the upper and lower limits of the frequency band are set to the frequency range corresponding to a 6dB drop in the peak frequency of the strain response; when the peak frequency of the strain response of the test piece changes by 10%, the test piece is considered to be damaged, the root mean square value of the strain response of the test piece is recorded, the number of fatigue cycles at the time of the test piece being damaged is recorded, and the least squares method is used to fit the fatigue SN curve.

[0079] The heat-static pressure-vibration combined loading fatigue SN curve test device and method of the present application have the following beneficial effects:

[0080] 1. It realizes precise control and independent loading of heat, static pressure and vibration loads, and has technical characteristics such as controllable load, simple structure and convenient operation;

[0081] 2. Negative pressure loading can be used to simulate the external overall negative pressure conditions of the honeycomb sandwich structure of the local composite panel when the aircraft is flying at high altitude;

[0082] 3. It can realize the thermal-static pressure-vibration combined loading fatigue SN curve test, which truly reflects the material / structure fatigue characteristics of the seriously loaded parts of civil aircraft.

[0083] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A heat-static pressure-vibration combined loading fatigue SN curve test device, characterized in that: include: A vibration table (8), the vibration table (8) comprising a vibration part and a static part, the vibration part being located at a central position of the static part; An air chamber (5), the air chamber (5) being connected to the vacuum pump (1) via an air pipe (2), the air chamber (5) having an upper opening at its upper end and a lower opening at its lower end, the air chamber (5) being arranged on the stationary part of the vibration table (8), a rubber sealing pad (14) being arranged between the air chamber (5) and the stationary part of the vibration table (8), and the opening at the lower end of the air chamber (5) corresponding to the vibration part of the vibration table (8); A cover plate (3), the cover plate (3) being mounted on the upper opening of the gas chamber (5), and a quartz glass plate (17) being arranged on the cover plate (3); A clamp (13), wherein the clamp (13) is fixedly mounted on the vibration part of the vibration table (8); A test piece (9), the test piece (9) being mounted on the fixture (13), and the test piece (9) being located in a closed cavity formed by the air chamber (5), the cover plate (3), the vibration table (8) and the rubber sealing pad (14), and a medium-temperature strain gauge (11) being mounted on the test piece (9); A quartz lamp heater (4), wherein the quartz lamp heater (4) is mounted on the quartz glass plate (17), and infrared radiation light from the quartz lamp heater (4) passes through the quartz glass plate (17) and irradiates onto the test piece (9) in the sealed cavity.

2. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 1 is characterized in that: A plurality of quartz glass windows (6) are arranged on the side wall of the gas chamber (5).

3. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 1 is characterized in that: A pressure transmitter (7) is installed on the air chamber (5), and the pressure transmitter (7) is connected to a pressure controller, through which the vacuum pump (1) is closed-loop controlled.

4. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 1 is characterized in that: A water cooling pipe (18) is installed on the cover plate (3), and the water cooling pipe (18) has a cooling water joint (15).

5. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 4 is characterized in that: A handle (16) is installed on the cover plate (3).

6. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 1, characterized in that: The fixture (13) comprises a base and a support platform, wherein: The base is fixedly mounted on the vibrating portion of the vibrating table (8); The support platform is arranged on the base, and the test piece (9) is pressed onto the support platform by a pressing block (10) and fixed with bolts.

7. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 6 is characterized in that: A high-temperature accelerometer is attached to the pressing block (10), and the high-temperature accelerometer is connected to a vibration controller, through which the vibration table (8) is closed-loop controlled.

8. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 1 is characterized in that: A thermocouple (12) is attached to the test piece (9), and the thermocouple (12) is connected to a thermal controller, through which the quartz lamp heater (4) is closed-loop controlled.

9. A heat-static pressure-vibration combined loading fatigue SN curve test method, based on the heat-static pressure-vibration combined loading fatigue SN curve test device according to any one of claims 1 to 8, characterized in that: include: Step 1: obtaining a first relative relationship between a strain response result of a test piece and a vibration load, and a second relative relationship between a strain response result of the test piece and a fatigue life through a vibration loading test; Step 2: determining the vibration load frequency and multiple vibration load magnitudes of the heat-static pressure-vibration combined loading test according to the first relative relationship and the second relative relationship; Step 3, respectively carry out heat-static pressure-vibration combined loading tests according to the determined vibration load frequency and different vibration load magnitudes, collect multiple sets of strain response results, and record the cumulative test time at the time of failure of the test piece, and calculate the number of fatigue cycles according to the vibration load frequency and the cumulative test time; Step 4: According to the strain response results and the number of fatigue cycles, the least squares method is used to fit the thermal-static pressure-vibration combined loading fatigue SN curve of the test piece.

10. The thermal-static-vibration combined loading fatigue SN curve testing device according to claim 9, characterized in that: In step 3, the number of fatigue cycles is calculated based on the vibration load frequency and the cumulative test time: The number of fatigue cycles is: Where, t is the cumulative test time, f1 is the lower limit of the vibration load frequency, and f2 is the upper limit of the vibration load frequency.

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