An ultra-high temperature thermomechanical fatigue testing system with a variable gas environment

Abstract

The present invention discloses an ultra-high temperature thermomechanical fatigue test system with a variable gas environment, comprising a hydraulic servo fatigue tester, a water cooling device, an air compressor, an inert gas tank, an operating computer, a three-way solenoid valve, a hydraulic servo fatigue tester controller, and a temperature controller. The heating device, the water cooling device, and the three-way solenoid valve are all connected to the temperature controller; the air compressor and the inert gas tank are connected to the three-way solenoid valve, and then the gas is applied to the test environment through a gas delivery pipe; the controller controls the mechanical force and strain loading, and after connecting and communicating with the temperature controller and the operating computer, the operating computer can realize the control of the change of the gas test environment and the temperature loading. The present invention can quickly realize the heating, insulation, and cooling control of the test material, and can enable the loaded specimen to be tested in different gas environments, which is of great significance to the development of ultra-high temperature fatigue and different environmental tests.

Description

Technical Field

[0001] The present invention relates to the technical field of fatigue testing, in particular to an ultra-high temperature thermomechanical fatigue testing system with a variable gas environment. Background Art

[0002] The hot-end components of an integrated aerospace vehicle are often subjected to ultra-high temperature thermal fatigue loads during service. In addition, as the flight altitude of the aerospace vehicle increases during flight, the oxygen content of the ambient gas will decrease as the altitude increases when entering the atmosphere at different altitudes, resulting in complex oxidation damage in an ultra-high temperature environment.

[0003] Because components in this service environment will produce various types of damage, such as fatigue damage, creep damage, and oxidation damage. There is interaction and coupling between these types of damage, which has a complex impact on structural components serving in ultra-high temperature environments, causing failure and fracture of structural components and triggering catastrophic accidents. Therefore, during the design stage of structural components, it is necessary to conduct fatigue test research based on the actual service environment experienced by the hot end components of integrated aerospace vehicles. This requires the test system to meet the test conditions of complex force / heat loading and gas environment changes on standard specimens, in order to explore the damage mechanism of the material and guide the reliability design of the components.

[0004] Conventional test equipment does not have the ability to perform ultra-high temperature loading and variable gas environments, and is unable to independently achieve functions that fit the actual service environment and explore different damage mechanisms. Specifically,

[0005] (1) The gas environment (oxygen content) of structural components in service under ultra-high temperature loading will change compared to the general air environment. Traditional high-temperature test equipment cannot change the gas environment of the specimen during the test, and thus cannot consider the damage suffered by the specimen in different gas environments, nor can it explore the effect of protective gas on the oxidation protection of structural components.

[0006] (2) Conventional fatigue test equipment uses non-enclosed heating. Compared with enclosed heating equipment, the temperature it can reach is lower and cannot meet the ultra-high temperature (2000°C) test environment required for the test.

[0007] (3) During the cycle heating process, the heating output power, water cooling output and air output rate are controlled, and comprehensive adjustments are made based on the real-time temperature data of the temperature sensor to achieve precise and rapid control of the heating-insulation-cooling process. Summary of the Invention

[0008] In view of the above-mentioned deficiencies in the prior art, the present invention aims to establish an ultra-high temperature thermomechanical fatigue testing system with a variable gas environment, wherein the ultra-high temperature environment referred to hereinafter is a 2000°C environment.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A variable-gas-environment, ultra-high-temperature thermomechanical fatigue testing system, designed to work with a hydraulic servo fatigue testing machine to implement high-temperature testing with cyclic heating under a variable-gas test environment, is characterized by comprising a hydraulic servo fatigue testing machine 1, a heating furnace 2, a heating and cooling device 3, an aluminum profile support 4, a water cooling device 5, an air compressor 6, an inert gas tank 7, an operating computer 8, a three-way solenoid valve 9, a hydraulic servo fatigue testing machine controller 10, and a temperature controller 11. The hydraulic servo fatigue testing machine 1 is connected to a hydraulic servo fatigue testing machine controller 10, and the operating computer 8 is connected to the hydraulic servo fatigue testing machine controller 10. The temperature controller 11 is also connected and communicates with the hydraulic servo fatigue testing machine controller 10. The heating device 3, water cooling device 5, and three-way solenoid valve are all connected to the temperature controller 11. The air compressor 6 and inert gas tank 7 are connected to the three-way solenoid valve 9, which then applies gas to the test environment through a gas delivery pipe 12. The controller 10 controls mechanical force and strain loading. After connecting and communicating with the temperature controller 11 and the operating computer 8, the operating computer can control changes in the gas test environment and temperature loading. The air compressor 6 and inert gas tank 7 are also connected to the three-way solenoid valve 9. The third pipeline channel of the three-way solenoid valve 9 is further divided into four air channels 12, which are connected to the furnace body 21. The three-way solenoid valve communicates with the controller 10 and is controlled by the operating computer 8. The heating device 3 is connected to the heating furnace device 2 and is mounted on the aluminum profile bracket 4. The ultra-high temperature thermomechanical fatigue test system comprises a gas delivery structure, a water cooling pipeline, a gas introduction part and a temperature control part.

[0011] The gas delivery structure is composed of four air delivery hoses 12 connected to the furnace body air inlet channel 21.4 through four connecting joints 13, and the gas is guided to the heat loading point of the specimen through four ceramic tubes 24; the cooling pipeline is composed of the furnace body pipeline 21.2 and the furnace cover pipeline 16.1, with two pipelines for the furnace body and the furnace cover, realizing one-in-one-out circulation of cooling water; in the thermal insulation structure, the graphite tube 29 is in the center, the small insulation tube 28 and the large insulation tube 27 are placed outward in sequence, and the two end covers 26 are respectively stuck between the furnace cover 16 and the large insulation tube 27 and placed at the bottom of the furnace body, and the four flame shielding covers 25 are divided into two groups and placed at the positions of the upper and lower furnace openings 21.5.

[0012] In the water-cooling pipeline, it is led out from the water-cooling device 5 and connected to the water inlet 21.2 of the furnace body and the water inlet 16.1 of the furnace cover respectively. After circulating inside the furnace body and the furnace cover, it is discharged from the furnace body water outlet 21.3 and the furnace cover water outlet 16.2 and connected back to the water-cooling device 5 by the water-cooling hose 19; Gas pipeline: The four ceramic tubes are placed in the furnace body air inlet channel 21.4, fixed by fastening bolts 14, and then connected to the joint 13 and the air inlet hose 12; Gas cooling pipeline: The gas is connected to the air cooling chuck 31 through the water-cooling hose 19. The cooling gas needs to be consistent with the gas in the gas delivery pipeline.

[0013] Gas introduction part: The inert gas tank 7 filled with protective gas is connected to the inlet of the three-way solenoid valve 9 through a hose, and the outlet of the three-way solenoid valve 9 is connected to the furnace body air inlet channel 21.4 through the gas delivery pipe 12. There is a ceramic tube 24 extending to the surface of the test specimen in the air inlet channel. The ceramic tube 24 is fixed in the furnace body air inlet channel 21.4 by fastening bolts 14.

[0014] Temperature control section: Temperature control is achieved through PID regulation. The main regulating device is the temperature controller 11. The heating device 3 and the gas cooling device 31 are both regulated by the temperature controller 11. The temperature sensor 23 is fixed in the furnace sensor pipe 21.1 by the fastening bolt 14. During the test, it measures the surface temperature of the test piece and transmits the real-time temperature data back to the temperature controller 11 after the test starts. Based on the comparison of the real-time temperature data fed back by the sensor and the temperature set in the test, the control system controls the output power and the air cooling amount for adjustment (such as Figure 4 The water cooling system inside the furnace body 21 and the furnace cover 16 is used to cool the heating furnace so that the outer surface of the heating furnace device 2 is lower than 50°C to prevent external test equipment from being damaged by excessively high temperatures.

[0015] Through the above treatment, the closed heating furnace device 2 can achieve an ultra-high temperature of 2000°C, and the outer surface temperature of the heating furnace device is maintained below 50°C through the water cooling circulation insulation of the furnace body, ensuring the normal operation of the external test equipment.

[0016] The test gas environment can be modified in real time based on test requirements. Structural components exposed to air at extremely high temperatures can suffer oxidative damage, and the oxygen content of the atmosphere surrounding the components changes as the aerospace vehicle's altitude increases. In the design of the present invention, signals from a computer 8 can be used to control the ratio of air and inert gas entering the three-way solenoid valve 9, thereby controlling the oxygen content of the output gas and exploring the impact of ambient gas changes on the test piece.

[0017] Mechanical loading is primarily achieved by the hydraulic servo fatigue testing machine 1, while temperature loading is primarily achieved by a heating device 3 and a cooling system (including water and air cooling) regulated by a temperature controller. Mechanical load measurement and control are primarily accomplished using conventional sensors and a multi-axis extensometer 30 equipped with the hydraulic servo fatigue testing machine. Temperature measurement is primarily accomplished by converting captured temperature signals into voltage signals using a temperature sensor thermocouple 23. Mechanical and temperature loading are coupled under the regulatory control of a controller 10 and are executed based on test commands issued by an operating computer 8. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall structure of the system described in the test method of the present invention;

[0019] Figure 2 It is a schematic diagram of the external appearance of the heating furnace device of the present invention;

[0020] Figure 3 This is an exploded view of the heating furnace device of the present invention;

[0021] Figure 4 This is the temperature control PID adjustment flow chart; DETAILED DESCRIPTION

[0022] In order to make the specific embodiments and details of the present invention clearer, Figures 1 to 3 Taking the ultra-high temperature fatigue test of needle-punched C / SiC composite materials as an example, the specific test steps are explained:

[0023] (1) Check that the connections between various control devices are normal. The heating device 3, thermocouple sensor 23, water cooling device 5 and three-way solenoid valve 9 are connected to the temperature controller 11 and are PID controlled. The hydraulic servo fatigue testing machine 1 is connected to the hydraulic servo fatigue testing machine controller 10. The operating computer 8 is connected to the hydraulic servo fatigue testing machine controller 10. At the same time, the temperature controller 11 is connected and communicated with the hydraulic servo fatigue testing machine controller 10. At this point, the test process can be fully controlled by the operating computer 8.

[0024] (2) After the heating furnace device 2 is installed, the water cooling pipeline, gas cooling pipeline and gas delivery pipeline are connected.

[0025] (3) Install the temperature sensor thermocouple 23 and fix it in the sensor channel 21.1 by tightening the bolts 14.

[0026] (4) Clamp the specimen and pass it through the specimen hole 21.5 of the heating furnace device. After adjusting the specimen position, first lock the upper chuck 1.1 of the hydraulic servo fatigue machine, and then adjust the lower chuck

[0027] 1.2 Lock the test piece after positioning.

[0028] (5) After completing the equipment installation and specimen clamping, turn on the power of each device, and then turn on the water cooling cycle, air cooling and gas delivery in sequence.

[0029] (6) After checking that each system is operating normally, use the computer to input the corresponding test loading parameters and carry out ultra-high temperature fatigue testing.

Claims

1. A variable gas environment ultra-high temperature thermomechanical fatigue testing system, which is used in conjunction with a hydraulic servo fatigue testing machine to implement a high temperature testing system with cyclic heating in a variable gas test environment; characterized by: The invention comprises a hydraulic servo fatigue testing machine (1), a heating furnace device (2), a heating device (3), an aluminum profile bracket (4), a water cooling device (5), an air compressor (6), an inert gas tank (7), an operating computer (8), a three-way solenoid valve (9), a hydraulic servo fatigue testing machine controller (10) and a heating controller (11); the hydraulic servo fatigue testing machine (1) is connected to the hydraulic servo fatigue testing machine controller (10), the operating computer (8) is connected to the hydraulic servo fatigue testing machine controller (10), and the heating controller (11) is connected to the hydraulic servo fatigue testing machine controller (10) for communication; the heating device (3) is connected to the water cooling device (5) and the three-way solenoid valve (9), and the heating device (3) is connected to the water cooling device (5) and the three-way solenoid valve (9). The three-way solenoid valves (9) are connected to the temperature controller (11); the air compressor (6) and the inert gas tank (7) are connected to the three-way solenoid valve (9), and the gas is applied to the test environment through the gas delivery pipe (12); the controller (10) controls the mechanical force and strain loading, and after the controller is connected and communicated with the temperature controller (11) and the operating computer (8), the real-time change control of the gas test environment and the temperature loading control are realized in the operating computer (8); the heating device (3) is connected to the heating furnace device (2), and the heating device (3) is installed on the aluminum profile bracket (4); the ultra-high temperature thermal mechanical fatigue test system has a gas delivery structure, a water cooling pipeline, a gas introduction part and a temperature control part; The test gas environment can be changed in real time during the test to conduct an oxidation protection test; the gas delivery structure is composed of four air delivery hoses (12) connected to the furnace body air inlet channel (21.4) through four connecting joints (13), and the gas is guided to the heat loading position of the specimen through four ceramic tubes (24); the cooling pipeline is composed of the furnace body pipeline (21.2) and the furnace cover pipeline (16.1); in the heat insulation structure, the graphite tube (29) is centered, the small insulation tube (28) and the large insulation tube (27) are placed outward in sequence, the two end covers (26) are respectively stuck between the furnace cover (16) and the large insulation tube (27) and placed at the bottom of the furnace body, and the four flame shielding covers (25) are divided into two groups and are located at the positions of the upper and lower furnace openings (21.5).

2. The ultra-high temperature thermomechanical fatigue testing system with a variable gas environment according to claim 1, characterized in that: Based on the closed annular cooling and heat preservation structure of the heating furnace device (2), the ultra-high temperature inside the heating furnace reaches 2000°C, and the outer surface temperature of the furnace body is lower than 50°C.

3. The ultra-high temperature thermomechanical fatigue testing system with a variable gas environment according to claim 1, characterized in that: The cooling and heating systems are controlled by PID.

4. The ultra-high temperature thermomechanical fatigue testing system with a variable gas environment according to claim 1, characterized in that: In the water cooling pipeline, the water is led out from the water cooling device (5) and connected to the water inlet (21.2) of the furnace body and the water inlet (16.1) of the furnace cover respectively. After circulating inside the furnace body and the furnace cover, it is discharged from the furnace body water outlet (21.3) and the furnace cover water outlet (16.2) and connected back to the water cooling device (5) through the water cooling hose (19); gas pipeline: four ceramic tubes are placed in the furnace body air inlet channel (21.4), fixed by fastening bolts (14), and then connected to the joint (13) and the air inlet hose (12); gas cooling pipeline: the gas is connected to the air cooling chuck (31) through the water cooling hose (19).

5. The ultra-high temperature thermomechanical fatigue testing system with a variable gas environment according to claim 1, characterized in that: Gas introduction part: The inert gas tank (7) filled with protective gas is connected to the inlet of the three-way solenoid valve (9) through a hose, and the outlet of the three-way solenoid valve (9) is connected to the furnace body air inlet channel (21.4) through a gas delivery pipe (12). The air inlet channel is provided with a ceramic tube (24) extending to the surface of the test specimen. The ceramic tube (24) is fixed in the furnace body air inlet channel (21.4) by fastening bolts (14).

6. The ultra-high temperature thermomechanical fatigue testing system with a variable gas environment according to claim 1, characterized in that: Temperature control part: Temperature control is achieved through PID regulation. The main regulating device is the temperature controller (11). The temperature heating device (3) and the gas cooling device (31) are both regulated by the temperature controller (11). The temperature sensor (23) is fixed in the furnace sensor pipe (21.1) by fastening bolts (14). During the test, the surface temperature of the test piece is measured, and the real-time temperature data is transmitted back to the temperature controller (11) after the test starts. The control system controls the output power and the air cooling size for adjustment based on the comparison between the real-time feedback temperature data of the sensor and the temperature set in the test. The internal water cooling system of the furnace body (21) and the furnace cover (16) is used to cool the temperature furnace, so that the outer surface of the temperature furnace device (2) is lower than 50°C, thereby preventing the external test equipment from being damaged by ultra-high temperature.

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