A high-temperature, high-speed, rotating bending fatigue stress online testing platform and measurement method

Abstract

A high-temperature, high-speed rotating bending fatigue stress online testing platform and measurement method primarily comprises a support base, mounted with a rotating hollow shaft driven in rotation by a drive device; a specimen secured to one end of the hollow shaft, mounted with a high-temperature self-compensating strain gauge; the high-temperature shielded signal leads of the high-temperature self-compensating strain gauge pass through the hollow shaft and are connected to corresponding electrodes of a sleeve assembly electrode; the sleeve assembly electrode is secured to the other end of the hollow shaft; each set of electrodes in the sleeve assembly electrode passes through a corresponding set of liquid metal conductive devices, which are electrically connected in sequence to a dynamic signal acquisition instrument and a computer; a heating device secured to the outside of the specimen, which heats the specimen at a set temperature. The present invention provides a high-temperature, high-speed rotating bending fatigue stress online testing platform and measurement method capable of accurately and in real time measuring the fatigue alternating stress changes experienced by a high-temperature, high-speed rotating specimen.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary bending fatigue testing, and in particular to an online real-time testing platform and a measuring method for high-temperature and high-speed rotary bending fatigue stress. Background Art

[0002] High-temperature rotary bending fatigue testing is primarily used to measure the cyclic alternating bending fatigue life of smooth material specimens in high-temperature environments. The stress-life curve, or SN curve, plots the fatigue limit stress σ (nominal stress) versus the fatigue life (number of cycles) N in high-temperature environments. This curve is then used to assess the material's high-temperature fatigue life. Currently, high-temperature rotary bending fatigue testing machines, both domestically and internationally, are only capable of producing SN curves at high temperatures, lacking the capability to measure the real-time alternating bending fatigue stress of rotating specimens under high-temperature conditions.

[0003] Conductive slip rings, also known as collector rings, rotary joints, current collectors, adapters, and commutators, are commonly used for power transmission in continuously rotating mechanisms. They primarily consist of a stator and rotor. Brushes are fixed to the stator or rotor, making electrical contact with corresponding conductive rings on the stator or rotor to transmit power and data. At low speeds (<1000 rpm), slip rings can be used for partial signal measurement. However, at high rotor speeds, the brushes and conductive rings rub rapidly, causing wear marks and abrasive particles to accumulate on the surface. Frictional heat also raises the temperature. These wear marks and abrasive particles cause changes in contact resistance, generating significant interference signals. The increased temperature can cause signal drift and distortion. Furthermore, the small size of bending fatigue specimens limits the use of slip rings. Developing direct, contact-free, non-interference, drift-free, and distortion-free online, real-time measurements of fatigue alternating stresses experienced by high-speed rotating mechanisms under high-temperature conditions has become a significant challenge. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide an online testing platform and measurement method for high-temperature, high-speed rotary bending fatigue stress. This platform not only obtains the high-temperature SN curve of the specimen, but also accurately measures the fatigue alternating stress changes experienced by the specimen in real time. The measurement device does not exert any additional force on the specimen, ensuring that the measured signal is a true fatigue alternating stress, free of interference, drift, and processing. Utilizing accurate and true fatigue alternating stress measurement curves helps reveal the patterns of cumulative fatigue damage and fatigue fracture mechanisms in high-speed rotary bending under high-temperature conditions.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A high-temperature, high-speed, rotating bending fatigue stress online testing platform includes a support base on which a hollow shaft is rotatably mounted, the hollow shaft being driven to rotate at high speed by a driving device; a specimen is fixed to one end of the hollow shaft, a high-temperature self-compensating strain gauge is mounted on the specimen, and a high-temperature shielded signal lead of the high-temperature self-compensating strain gauge passes through the hollow shaft and is connected to a corresponding electrode of a sleeve-combined electrode; the sleeve-combined electrode is fixed to the other end of the hollow shaft;

[0007] Each set of electrodes of the sleeve combined electrode passes through a set of liquid metal conductive devices, and the liquid metal conductive devices are electrically connected to a dynamic signal acquisition instrument and a computer in sequence;

[0008] A heating device is fixed outside the sample, and the heating device heats the sample.

[0009] The sleeve combined electrode comprises a sleeve positive electrode and a sleeve negative electrode, and the sleeve positive electrode and the sleeve negative electrode are sleeved and fixed with each other and are insulated from each other.

[0010] The two electrodes of the sleeve combination electrode are gradually lengthened from the outside to the inside and extend out gradually to the left and right.

[0011] The liquid metal conductive device includes an outer wall of a liquid metal device, which is connected to a liquid device head to form a sealed container. High-speed waterproof bearings for the sleeve combination electrode seal to pass through are installed on the left and right sides of the sealed container. Liquid metal is arranged in the sealed container, and a positive electrode of a conductive column and a negative electrode of a conductive column are arranged on one side of the sealed container.

[0012] The liquid metal is a gallium-indium based alloy that is liquid at room temperature.

[0013] The sample is connected to one end of the hollow shaft through a spring chuck; the sleeve combination electrode is fixed on the spring chuck through a C-shaped adapter clip, and the spring chuck is connected to the other end of the hollow shaft; the spring chuck is provided with a wire hole.

[0014] The driving device includes a transmission wheel installed on a hollow shaft, a corresponding high-speed motor output end is connected to a passive wheel, and a belt is passed between the transmission wheel and the passive wheel; a counter is installed at the transmission wheel, and the counter records the number of fatigue cycles.

[0015] The heating device comprises an induction coil, which is connected to a heating controller via a water conduit, the heating controller is electrically connected to an infrared temperature sensor, and the infrared temperature sensor is directly opposite to the sample.

[0016] The induction coil and the water conduit are made of copper alloy, aluminum alloy, stainless steel, nickel alloy or titanium alloy, ensuring electrical conductivity while the internal cooling water cools the induction coil.

[0017] A method for measuring high-temperature, high-speed rotation bending fatigue stress using an online testing platform is disclosed. The high-temperature, high-speed rotation fatigue alternating stress of a specimen is collected in real time using a high-temperature self-compensating strain gauge. The collected signal is coaxially output via a high-temperature shielded signal lead and then connected to a sleeve combination electrode. The sleeve combination electrode is fixed to a hollow shaft by a spring chuck and rotates synchronously with the specimen. The sleeve combination electrode and the specimen are separated from each other without generating any additional force. The two electrodes of the sleeve combination electrode respectively pass through and are immersed in two independent liquid metal conductive devices. During high-speed rotation, the signal is transmitted to a dynamic signal acquisition instrument via the liquid metal and the signal wire, and the collected data is recorded in real time by a computer via a data line.

[0018] A high-temperature, high-speed, rotating bending fatigue stress online testing platform measurement method comprises the following steps:

[0019] Step 1) Fix one end of the specimen with the high-temperature self-compensating strain gauge attached to the hollow shaft with a spring chuck. Before fixing, pass the high-temperature shielded signal lead of the high-temperature self-compensating strain gauge through the spring chuck and the hollow shaft, and then connect the positive and negative electrodes of the lead to the positive and negative electrodes of the sleeve combination electrode respectively.

[0020] Step 2) Place the induction coil into the sample and align the infrared temperature sensor probe with the center of the sample;

[0021] Step 3) Step 3: Fix the mounting connector to the other end of the specimen and hang the weight plate according to the fatigue load;

[0022] Step 4) Insert the sleeve-combined electrode with the transition insulating sleeve into the C-shaped adapter clamp, and then use a spring chuck to fix the C-shaped adapter clamp and the sleeve-combined electrode together at the other end of the hollow shaft;

[0023] Step 5) After the two sleeve positive electrodes and sleeve negative electrodes extending from the sleeve combination electrode are passed through two independent liquid metal conductive devices, liquid metal is injected into the conductive devices to immerse the passed sleeve positive electrodes and sleeve negative electrodes;

[0024] Step 6) Connect the negative electrode of the signal wire and the positive electrode of the signal wire to the negative electrode of the conductive column and the positive electrode of the conductive column, then connect the dynamic signal acquisition instrument, and use a data cable to connect the computer and the dynamic signal acquisition instrument. Open the stress acquisition control software, adjust the strain gauge parameters to clear the bridge balance, and prepare to collect fatigue alternating stress data;

[0025] Step 7) Start the heating controller, set the heating temperature and heat the sample. The heating temperature is collected in real time by the infrared temperature sensor and fed back to the heating controller to form a closed-loop control;

[0026] Step 8) Start the high-speed motor, the belt drives the transmission wheel and the hollow shaft to rotate, and the counter records the number of fatigue cycles;

[0027] Step 9) After the sample breaks, stop the high-speed motor and read the fatigue life times recorded in the control box;

[0028] Step 10), stop the stress acquisition control software and store the fatigue fracture full life stress change curve;

[0029] Step 11) Repeat the above steps to complete the SN curve and real-time stress change curve.

[0030] The present invention provides an online testing platform and measurement method for high-temperature and high-speed rotating bending fatigue stress, which has the following technical effects:

[0031] 1) Compared with the existing high-temperature bending fatigue test device, the present invention can obtain the general high-temperature stress-life curve (SN curve) and measure the change process of high-speed rotation bending fatigue stress under high temperature conditions in real time online.

[0032] 2) Due to the coaxial signal transmission design, the test device is separated from the test object and does not generate any additional force on the specimen.

[0033] 3) Liquid metal is used as the signal transmission medium of the rotating mechanism, so no friction occurs when the rotating electrode and the liquid metal transmit signals, thereby avoiding the signal interference and drift problems caused by high-speed rotation friction marks and friction temperature rise of traditional conductive devices such as contact conductive slip rings, and realizing true and accurate measurement of high-temperature and high-speed rotation bending fatigue alternating stress without interference and drift.

[0034] 4) By setting up a heating device, the heating device heats the sample and controls the temperature within a certain range.

[0035] 5) Patent application number "201720985741.9," titled "A Liquid Metal Conductive Slip Ring," utilizes a ring + conductor structure, with the ring filled with liquid metal and the conductor inserted into the ring cavity to enable electrical signal transmission. However, the conductor in this device is a conductive sheet that does not pass through the liquid metal, resulting in only a single-level signal output. This application, on the other hand, utilizes multiple coaxially arranged cylindrical electrodes that independently pass through corresponding groups of liquid metal, enabling coaxial multi-level signal output. The referenced document, however, only outputs a single-pole signal and cannot achieve coaxial multi-pole signal output. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and examples:

[0037] Figure 1 It is a structural schematic diagram of the present invention.

[0038] Figure 2 This is a schematic diagram of the connection between the high-temperature self-compensating strain gauge signal line and the sleeve combined electrode in the present invention.

[0039] Figure 3 This is a schematic diagram of the connection between the sleeve combined electrode and the liquid metal conductive device in the present invention.

[0040] Figure 4 Schematic diagram of the complete transmission route of the rotational alternating stress measurement signal in the present invention.

[0041] Figure 5 It is a schematic diagram of the local structure of the present invention.

[0042] Figure 6 Schematic diagram of the counting device in the present invention.

[0043] Figure 7 Schematic diagram of the weight loading device in the present invention.

[0044] Figure 8 It is a structural schematic diagram of the spring chuck in the present invention.

[0045] In the figure: high-speed motor 1, mounting connector 2, induction coil 3, water conduit 31, high-temperature self-compensating strain gauge 4, high-temperature shielded signal lead 5, lead positive electrode 51, lead negative electrode 52, spring chuck 6, wire hole 61, weight plate 7, hook 71, sample 8, bearing 81, infrared temperature sensor 9, infrared wire 91, heating controller 10, control box 11, power control line 111, counter 12, counting wire 121, support base 13, liquid gold conductive support platform 131, shaft support base 132, dynamic signal acquisition instrument 14, computer 15, data line 16, signal wire negative electrode 17, signal wire positive electrode 171, liquid metal conductive device 18, liquid metal device outer wall 181, high-speed waterproof bearing 182, conductive column positive electrode 183, liquid metal 184, conductive column negative electrode 185, liquid device head 186, sleeve combined electrode 19, sleeve positive electrode 191, sleeve negative electrode 192, C-shaped adapter clip 20, transition insulation sleeve 201, hollow shaft 21, high-speed bearing 211, transmission wheel 22, counting hole 221, belt groove 222, tightening screw hole 223, belt 23. DETAILED DESCRIPTION

[0046] like Figure 1 、 Figure 5As shown, a high-temperature, high-speed rotating bending fatigue stress online testing platform includes a support base 13, on which are mounted a liquid metal conductive support platform 131 and a rotating shaft support base 132. The liquid metal conductive support platform 131 is used to support the liquid metal conductive device 18; the rotating shaft support base 132 is provided in two sets, and a hollow shaft 21 is rotatably mounted on the rotating shaft support base 132 via a high-speed bearing 211. The hollow shaft 21 is driven by a belt transmission mechanism consisting of a drive pulley 22 and a belt 23, and a high-speed motor 1. The rotation speed of the high-speed motor 1 is adjustable between 3,000 and 20,000 rpm.

[0047] like Figure 1 、 Figure 5 、 Figure 8 As shown, a spring chuck 6 is fixed to one end of the hollow shaft 21, and the sample 8 is mounted on the hollow shaft 21 through the spring chuck 6 and can rotate synchronously with the hollow shaft 21. The spring chuck 6 is provided with a wire hole 61 for the high-temperature shielded signal lead 5 to pass through.

[0048] like Figure 1-3 As shown, a high-temperature self-compensating strain gauge 4 is installed on sample 8. Its high-temperature shielded signal lead 5 passes through a wire hole 61 and is connected to the corresponding electrode of the sleeve assembly electrode 19. The sleeve assembly electrode 19, equipped with a transition insulating sleeve 201, is inserted into and secured in a C-shaped adapter clamp 20. The C-shaped adapter clamp 20 is then secured to the other end of the hollow shaft 21 using a spring chuck 6. The transition insulating sleeve 201 is installed on the sleeve assembly electrode 19, and then forms an interference fit with the adapter clamp 20. The provision of the transition clamp 201 provides insulation.

[0049] like Figure 2 As shown, the high-temperature shielded signal lead 5 includes a positive lead 51 and a negative lead 52 .

[0050] like Figure 2-3 As shown, the sleeve combination electrode 19 consists of two groups of electrodes, namely a sleeve positive electrode 191 and a sleeve negative electrode 192 , wherein the lead positive electrode 51 is electrically connected to the sleeve positive electrode 191 , and the lead negative electrode 52 is electrically connected to the sleeve negative electrode 192 .

[0051] like Figure 3 As shown, the sleeve positive electrode 191 and the sleeve negative electrode 192 are made of metal conductive material. The sleeve positive electrode 191 and the sleeve negative electrode 192 are fixed with insulating glue after being sleeved together to ensure that they are insulated from each other and do not interfere with each other.

[0052] like Figure 3As shown, the two electrodes of the sleeve combination electrode 19 gradually become longer from the outside to the inside and extend gradually to the left and right. For example, in the two sets of electrodes, the sleeve negative electrode 192 is nested in the sleeve positive electrode 191 and both ends extend outside the sleeve positive electrode 191.

[0053] like Figure 3 As shown, the two sets of electrodes of the sleeve combined electrode 19 pass through a set of liquid metal conductive devices 18 respectively. Figure 3 As shown, two sets of liquid metal conductive devices 18 are labeled a and b from right to left. The positive sleeve electrode 191 passes through a and contacts the liquid metal 184 in a, while the negative sleeve electrode 192 passes through b and contacts the liquid metal 184 in b. As the sleeve electrode 19 rotates in the liquid metal 184, it transmits signals through the liquid metal 184 to the signal wire connectors (positive conductive column 183 and negative conductive column 185) on the liquid device head 186.

[0054] like Figure 3-4 As shown, the liquid metal conductive device 18 includes a liquid metal device outer wall 181, which is connected to a liquid device head 186 to form a sealed container. The sealed container is equipped with high-speed waterproof bearings 182 on both sides for the sleeve combination electrode 19 to pass through in a sealed manner. Liquid metal 184 is placed in the sealed container. One side of one sealed container is provided with a conductive column positive electrode 183, and the other side of the sealed container is provided with a conductive column negative electrode 185. Here, the liquid metal device outer wall 181 and the liquid device head 186 are both made of insulating rubber material, and the high-speed waterproof bearings 182 are made of insulating ceramic wear-resistant material.

[0055] Preferably, the liquid metal 184 is a liquid gallium-indium-based alloy at room temperature, thereby ensuring that the sleeve positive electrode 191, the sleeve negative electrode 192 immersed therein can achieve contactless signal communication with the conductive column positive electrode 183, and the conductive column negative electrode 185 at room temperature.

[0056] like Figure 3-4 As shown, a dynamic signal acquisition device 14 is mounted on one side of the workbench. Two sets of signal wire connectors on two sets of liquid metal conductive devices 18 are connected to the negative electrode 17 and the positive electrode 171 of the signal wire, respectively. The other ends of the negative electrode 17 and the positive electrode 171 of the signal wire are connected to the dynamic signal acquisition device 14. The dynamic signal acquisition device 14 is electrically connected to a computer 15 via a data cable 16.

[0057] like Figure 6 As shown, a counting hole 221 is provided on the transmission wheel 22, and a counter 12 is installed at a suitable position below the transmission wheel 22. The counter 12 is connected to the control box 11 through a counting wire 121. The counter 12 counts and records the number of fatigue cycles.

[0058] A heating device is attached to the outside of sample 8, heating sample 8 and controlling its temperature within a certain range. The heating device includes an induction coil 3, which is connected to a heating controller 10 via a water conduit 31 (water conduit 31 is both electrically conductive and water-conducting; induction heating utilizes non-contact alternating electromagnetic heating, unlike heat conduction). The heating controller 10 is electrically connected to an infrared temperature sensor 9, which is positioned directly opposite sample 8 and is used to detect its temperature.

[0059] In addition, if Figure 7 As shown, a mounting connector 2 is installed on one side of the specimen 8, and a weight plate 7 is mounted on the lower end of the mounting connector 2 via a hook 71. In this device, power is provided by a high-speed motor 1, which drives the specimen 8 to rotate via a belt 23 and a drive pulley 22. The specimen 8 is subjected to a fatigue load via the weight plate 7. During rotation, the specimen is heated by an induction coil. The number of fatigue cycles is recorded by a counter 12. The test is stopped after the specimen breaks, and the cycle count is read from the counter. After repeated sets of tests, a high-temperature fatigue SN curve is plotted based on the fatigue load and the number of cycles.

[0060] A method for online measurement of high-temperature, high-speed rotating bending fatigue stress comprises the following steps:

[0061] Step 1) Secure one end of the sample 8 with the high-temperature self-compensating strain gauge 4 attached to the hollow shaft 21 using a spring chuck 6. Before securing, pass the high-temperature shielded signal lead 5 of the high-temperature self-compensating strain gauge 4 through the spring chuck 6 and the hollow shaft 21, and then connect the lead positive electrode 51 and lead negative electrode 52 to the sleeve positive electrode 191 and sleeve negative electrode 192 of the sleeve combination electrode 19 accordingly.

[0062] Step 2) Insert the induction coil 3 into the sample 8 and align the probe of the infrared temperature sensor 9 with the middle of the sample 8;

[0063] Step 3) Step 3: Fix the mounting connector 2 to the other end of the specimen 8 and hang the weight plate 7 according to the fatigue load;

[0064] Step 4) Insert the sleeve combination electrode 19 into the C-shaped adapter clamp 20, and then use the spring chuck 6 to fix the C-shaped adapter clamp 20 and the sleeve combination electrode 19 together to one end of the hollow shaft 21;

[0065] Step 5) After the two sleeve positive electrodes 191 and sleeve negative electrodes 192 extending from the sleeve combined electrode 19 are passed through two independent liquid metal conductive devices 18, liquid metal 184 is injected into the conductive devices to immerse the passed sleeve positive electrodes 191 and sleeve negative electrodes 192;

[0066] Step 6) Connect the negative electrode 185 of the conductive column and the positive electrode 183 of the conductive column with the negative electrode 17 of the signal wire and the positive electrode 171 of the signal wire, then connect the dynamic signal acquisition instrument 14, and connect the computer 15 and the dynamic signal acquisition instrument 14 with the data line 16. Open the stress acquisition control software, adjust the strain gauge parameters to reset the bridge balance, and prepare to collect fatigue alternating stress data;

[0067] Step 7), start the heating controller 10, set the heating temperature and heat the sample. The heating temperature is collected in real time by the infrared temperature sensor 9 and fed back to the heating controller 10 to form a closed-loop control;

[0068] Step 8), start the high-speed motor 1, the belt 23 drives the transmission wheel 22 and the hollow shaft 21 to rotate, and the counter 12 records the number of fatigue cycles;

[0069] Step 9), after the sample breaks, stop the high-speed motor 1 and read the fatigue life times recorded by the control box 11;

[0070] Step 10), stop the stress acquisition control software and store the fatigue fracture full life stress change curve;

[0071] Step 11) Repeat the above steps to complete the SN curve and real-time stress change curve.

Claims

1. A high-temperature, high-speed, rotating bending fatigue stress online testing platform, characterized by: The invention comprises a support base (13), a hollow shaft (21) is rotatably mounted on the support base (13), and the hollow shaft (21) is driven to rotate at high speed by a driving device; a sample (8) is fixed to one end of the hollow shaft (21), a high-temperature self-compensating strain gauge (4) is mounted on the sample (8), and a high-temperature shielded signal lead (5) of the high-temperature self-compensating strain gauge (4) passes through the hollow shaft (21) and is connected to the corresponding electrode of the sleeve combination electrode (19); the sleeve combination electrode (19) is fixed to the other end of the hollow shaft (21); Each set of electrodes of the sleeve combined electrode (19) passes through a corresponding set of liquid metal conductive devices (18), and the liquid metal conductive devices (18) are electrically connected to the dynamic signal acquisition instrument (14) and the computer (15) in sequence; A heating device is fixed outside the sample (8), and the heating device heats the sample (8) at a set temperature; The sleeve combined electrode (19) comprises a sleeve positive electrode (191) and a sleeve negative electrode (192), and the sleeve positive electrode (191) and the sleeve negative electrode (192) are sleeved together and fixed with insulating glue to maintain insulation between them. The two electrodes of the sleeve combined electrode (19) gradually lengthen from the outside to the inside and extend out gradually to the left and right; The liquid metal conductive device (18) includes a liquid metal device outer wall (181), the liquid metal device outer wall (181) is connected to a liquid device head (186) to form a sealed container, high-speed waterproof bearings (182) for the sleeve combination electrode (19) to pass through in a sealed manner are installed on the left and right sides of the sealed container, liquid metal (184) is provided in the sealed container, and a conductive column positive electrode (183) and a conductive column negative electrode (185) are provided on one side of the sealed container; The sample (8) is connected to one end of the hollow shaft (21) through a spring chuck (6); the sleeve combination electrode (19) equipped with a transition insulating sleeve (201) is fixed on the spring chuck (6) through a C-shaped adapter clamp (20), and the spring chuck (6) is connected to the spring chuck (6) at the other end of the hollow shaft (21); the spring chuck (6) is provided with a wire hole (61).

2. The high-temperature, high-speed, rotating bending fatigue stress online testing platform according to claim 1, characterized in that: The liquid metal (184) is a liquid gallium-indium-based alloy at room temperature.

3. The high-temperature, high-speed, rotating bending fatigue stress online testing platform according to claim 2, characterized in that: The driving device includes a transmission wheel (22) mounted on a hollow shaft (21), a driven wheel connected to the output end of the corresponding high-speed motor (1), and a belt (23) is wound between the transmission wheel (22) and the driven wheel; a counter (12) is mounted on the transmission wheel (22), and the counter (12) records the number of fatigue cycles.

4. The high-temperature, high-speed, rotating bending fatigue stress online testing platform according to claim 3, characterized in that: The heating device comprises an induction coil (3), the induction coil (3) is connected to a heating controller (10) via a water conduit (31), the heating controller (10) is electrically connected to an infrared temperature sensor (9), and the infrared temperature sensor (9) is directly opposite to the sample (8); the induction coil (3) and the water conduit (31) are made of copper alloy, aluminum alloy, stainless steel, nickel alloy or titanium alloy, ensuring electrical conductivity while internal cooling water cools the induction coil (3).

5. The high-temperature, high-speed, rotating bending fatigue stress online testing platform according to claim 4, characterized in that: The high-temperature, high-speed rotation fatigue alternating stress of the sample (8) is collected in real time through a high-temperature self-compensating strain gauge (4). The collected signal is coaxially output through a high-temperature shielded signal lead (5) and connected to a sleeve combination electrode (19). The sleeve combination electrode (19) is fixed on a hollow shaft (21) by a spring clamp (6) and rotates synchronously with the sample (8). The sleeve combination electrode (19) and the sample (8) are separated from each other without generating any additional force. The two electrodes of the sleeve combination electrode (19) respectively pass through and are immersed in two independent liquid metal conductive devices (18). When rotating at high speed, the signal is transmitted to a dynamic signal acquisition instrument (14) through the liquid metal and the signal wire, and the collected data is recorded in real time by a computer (15) through a data line.

6. The method for measuring high-temperature, high-speed, rotating bending fatigue stress online testing platform according to claim 5 comprises the following steps: Step 1) Fix one end of the sample (8) with the high-temperature self-compensating strain gauge (4) attached to it on the hollow shaft (21) using a spring chuck (6); before fixing, first pass the high-temperature shielded signal lead (5) of the high-temperature self-compensating strain gauge (4) through the spring chuck (6) and the hollow shaft (21), and then connect the lead positive electrode (51) and the lead negative electrode (52) to the sleeve positive electrode (191) and the sleeve negative electrode (192) of the sleeve combination electrode (19) accordingly; Step 2), insert the induction coil (3) into the sample (8), and align the probe of the infrared temperature sensor (9) with the middle of the sample (8); Step 3) Step 3: Fix the mounting connector (2) to the other end of the specimen (8) and hang the weight plate (7) according to the fatigue load; Step 4), insert the sleeve combination electrode (19) equipped with the transition insulation sleeve (201) into the C-shaped adapter clamp (20), and then use the spring chuck (6) to fix the C-shaped adapter clamp (20) and the sleeve combination electrode (19) together at one end of the hollow shaft (21); Step 5), after the two sleeve positive electrodes (191) and the sleeve negative electrode (192) extending from the sleeve combined electrode (19) are passed through two independent liquid metal conductive devices (18), liquid metal (184) is injected into the conductive devices to immerse the passed sleeve positive electrode (191) and the sleeve negative electrode (192); Step 6) Connect the negative electrode of the signal wire (17) and the positive electrode of the signal wire (171) to the negative electrode of the conductive column (185) and the positive electrode of the conductive column (183), then connect the dynamic signal acquisition instrument (14), and connect the computer (15) and the dynamic signal acquisition instrument (14) with the data line (16), open the stress acquisition control software, adjust the strain gauge parameters to clear the bridge balance, and prepare to collect fatigue alternating stress data; Step 7), start the heating controller (10), set the heating temperature and heat the sample, the heating temperature is collected in real time by the infrared temperature sensor (9) and fed back to the heating controller (10) to form a closed-loop control; Step 8), starting the high-speed motor (1), the belt (23) drives the transmission wheel (22) and the hollow shaft (21) to rotate, and the counter (12) records the number of fatigue cycles; Step 9), after the sample breaks, the high-speed motor (1) is stopped, and the control box (11) is read to record the number of fatigue life; Step 10), stop the stress acquisition control software and store the fatigue fracture full life stress change curve; Step 11) Repeat the above steps to complete the SN curve and real-time stress change curve.

Images