System and method for blade fretting fatigue test

Abstract

The invention discloses a system and a method for a blade fretting fatigue experiment, the experiment system comprises a vertical loading device, a horizontal loading device and a vibration loading device, the vertical loading device comprises an upper connector and a lower connector which are used for being connected with a mortise test piece; the upper connecting body and the lower connecting body can move relatively in the vertical direction so as to provide vertical pulling force. The horizontal loading device comprises a first connecting body used for being connected with a first blade test piece and a second connecting body used for being connected with a second blade test piece, and the first connecting body and the second connecting body can relatively move in the horizontal direction to provide horizontal pulling force; the vibration loading device comprises a third connecting body connected with a blade body of the blade test piece and a vibrator connected with the third connecting body, and a vertical vibration load generated by the vibrator is transmitted to the blade test piece through the third connecting body. The experimental system provided by the invention can well simulate the actual stress environment of the blade, and is convenient to better carry out related research work on the aero-engine blade.

Description

Technical Field

[0001] The invention relates to the technical field of experimental instruments, and in particular to a system and method for blade micro-motion fatigue testing. Background Art

[0002] Blades are key parts of aircraft engines. According to their location and function, they can be divided into fan blades, compressor blades and turbine blades. When the engine rotates at high speed, the blades will be subjected to a variety of complex loads such as centrifugal loads caused by high-speed rotation and complex airflow disturbances. Complex cyclic alternating loads will cause vibration fatigue problems of the blades, which will lead to engine failure. Therefore, the safety of the blades is crucial to the performance and reliability of aircraft engines.

[0003] Blade micro-motion fatigue test is an important means to study aircraft engine blades, but the current experimental equipment generally only performs uniaxial stretching on the blades, and the vibration frequency is low, which cannot well simulate the actual stress environment of the blades. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a system and method for blade micro-fatigue testing, so as to better simulate the actual stress environment of the blade, so as to better carry out relevant research work on aircraft engine blades.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A system for blade micro-motion fatigue testing, comprising:

[0007] A vertical loading device, comprising an upper connector connected to the upper end of the mortise and tenon specimen and a lower connector connected to the lower end of the mortise and tenon specimen, wherein the upper connector and the lower connector are capable of relative vertical movement to apply a vertical tensile force to the mortise and tenon specimen to expand and deform the mortise and tenon specimen;

[0008] A horizontal loading device, comprising a first connector connected to an end of the first blade specimen away from the tenon and a second connector connected to an end of the second blade specimen away from the tenon, wherein the first connector and the second connector are capable of relative movement in a horizontal direction to apply a horizontal tensile force to the first blade specimen and the second blade specimen connected to the tenon-groove specimen;

[0009] The vibration loading device includes a third connector connected to the blade body of the first blade specimen or the second blade specimen and a vibrator connected to the third connector, and the vertical vibration load generated by the vibrator is transmitted to the first blade specimen or the second blade specimen through the third connector.

[0010] Optionally, in the above system, the horizontal loading device comprises:

[0011] A first screw group for carrying the first connecting body, the first screw group comprising two first screws arranged at the same height and parallel to each other, the first connecting body being threadedly connected to the two first screws;

[0012] The second screw group is used for carrying the second connecting body, wherein the second screw group includes two second screws which are arranged at the same height and parallel to each other, and the second connecting body is threadedly connected to the two second screws.

[0013] Optionally, in the above system, the first screw and the corresponding second screw are coaxially arranged and one end close to each other is connected to the same first support seat, and the first screw and the second screw are respectively rotatably connected to the first support seat.

[0014] Optionally, in the above system, the horizontal loading device comprises:

[0015] A second support seat, located at one end of the first lead screw away from the first support seat, and rotatably connected to the two first lead screws;

[0016] A third support seat, located at one end of the second lead screw away from the first support seat, and rotatably connected to the two second lead screws;

[0017] A horizontally arranged connecting rod connects the second supporting seat and the third supporting seat.

[0018] Optionally, in the above system, the upper connector includes an inverted U-shaped first holder for connecting to the upper end of the mortise and tenon specimen, the first holder is provided with a plurality of first connection holes for passing first bolts, and the first bolts horizontally pass through first through holes provided at the upper end of the mortise and tenon specimen;

[0019] The lower connector includes a U-shaped second holder for connecting to the lower end of the mortise and tenon specimen, the second holder is provided with a plurality of second connection holes for passing second bolts, and the second bolts horizontally pass through the second through holes provided at the lower end of the mortise and tenon specimen.

[0020] Optionally, in the above system, the vibrator includes an armature, an iron core and a coil, the armature is connected to the third connector, the vibration loading device includes a frequency converter electrically connected to the coil and a vibration base fixedly connected to the iron core, and the iron core is located on the top of the vibration base.

[0021] Optionally, the above system includes:

[0022] Data acquisition card, electrically connected to the host computer;

[0023] A force sensor, mounted on the first connector and the second connector, and electrically connected to the data acquisition card via a signal amplifier;

[0024] The dynamic force sensor is installed on the third connector and is electrically connected to the data acquisition card via a signal conditioner.

[0025] Optionally, the above system includes a high-speed camera for continuously taking pictures of the loaded test piece and transmitting the pictures to the host computer.

[0026] Optionally, the above system includes:

[0027] A driving motor, used to provide power for the first connecting body and the second connecting body to move relative to each other in a horizontal direction;

[0028] The motor driver is electrically connected to the driving motor and the data acquisition card, and is used to receive the pulse frequency sent by the data acquisition card to adjust the output torque of the driving motor.

[0029] A method for blade micromotion fatigue test, using the system for blade micromotion fatigue test disclosed in any one of the above items, the method comprising:

[0030] Take the mortise and tenon specimen, the first blade specimen, and the second blade specimen;

[0031] The mortise and tenon test piece is mounted on the vertical loading device and fixedly connected to the upper connector and the lower connector;

[0032] The first blade specimen and the second blade specimen are respectively horizontally mounted on the tongue and groove specimen, and are respectively fixedly connected to the first connector and the second connector of the horizontal loading device;

[0033] The third connector of the vibration loading device is installed on the first blade specimen or the second blade specimen and fixedly connected;

[0034] The upper connector and the lower connector move away from each other in the vertical direction to apply vertical tension to the mortise and tenon specimen, the first connector and the second connector move away from each other in the horizontal direction to apply horizontal tension to the first blade specimen and the second blade specimen, and the vibrator of the vibration loading device generates a vertical vibration load and transmits it to the first blade specimen or the second blade specimen connected to the third connector through the third connector.

[0035] The system for blade micro-motion fatigue test provided by the present invention has the following beneficial effects:

[0036] The system of the present application not only includes a horizontal loading device capable of outputting horizontal loads to simulate the centrifugal loads that the blades are subjected to during operation, but also includes a vertical loading device capable of outputting vertical loads to simulate the expansion and deformation of the mortise and tenon when the engine is actually working, and a vibration loading device capable of outputting disturbance loads in the vertical direction to simulate the vibration loads generated by airflow disturbances. Therefore, the experimental system provided by the present application can well simulate the actual stress environment of the blades, making it easier to carry out relevant research work on aircraft engine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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 or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0038] Figure 1 is a schematic diagram of a system for blade micro-motion fatigue testing according to an embodiment of the present invention;

[0039] Figure 2 is a top view of a horizontal loading device according to an embodiment of the present invention.

[0040] The markings in the figure are:

[0041] 110, upper connector; 111, first holder; 120, lower connector; 121, second holder;

[0042] 210, first connector; 211, fixture; 220, drive motor; 230, motor driver; 241, first lead screw; 242, second lead screw; 251, first support seat; 252, second support seat; 253, third support seat; 260, connecting rod; 270, reducer; 280, coupling;

[0043] 310, vibration base; 321, iron core; 322, coil; 323, armature; 330, third connector; 340, input reactor; 350, input filter; 360, frequency converter; 370, output filter; 380, output reactor;

[0044] 410, force sensor; 420, dynamic force sensor; 510, signal amplifier; 520, signal conditioner; 610, high-speed camera; 620, lighting device; 700, data acquisition card; 800, host computer; 901, first blade specimen; 902, second blade specimen; 903, mortise and tenon specimen. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be described below in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the technical solutions in the present invention, all other technical solutions obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0047] In the description of this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0048] See also Figure 1 and Figure 2The embodiment of the present invention provides a system for blade micro-motion fatigue test, including a vertical loading device, a horizontal loading device and a vibration loading device, wherein the vertical loading device includes an upper connector 110 connected to the upper end of the tenon and groove specimen 903 and a lower connector 120 connected to the lower end of the tenon and groove specimen 903, and the upper connector 110 and the lower connector 120 can move relative to each other in the vertical direction to apply a vertical tensile force to the tenon and groove specimen 903 to expand and deform the tenon and groove specimen 903; the horizontal loading device includes a first connector 210 connected to an end of the first blade specimen 901 away from the tenon and a lower connector 120 connected to the lower end of the tenon and groove specimen 903; ... In the second connector (not marked in the figure) connected to the end of the second blade specimen 902 away from the tenon, the first connector 210 and the second connector can move relative to each other in the horizontal direction to apply horizontal tension to the first blade specimen 901 and the second blade specimen 902 connected to the tenon specimen 903; the vibration loading device includes a third connector 330 for connecting to the blade body of the first blade specimen 901 or the second blade specimen 902 and a vibrator connected to the third connector 330, and the vertical vibration load generated by the vibrator is transmitted to the first blade specimen 901 or the second blade specimen 902 through the third connector 330.

[0049] The tenon specimen 903 is a specimen provided with a tenon, and the tenon can be adapted and installed with the tenon of the blade specimen, that is, the tenon and the tenon shape match, for example, it can be a dovetail shape or a fir tree shape. The blade specimen is a specimen with blade structural characteristics made for blade micro-motion fatigue testing. For example, the blade specimen can be made in a 1:1 ratio according to the actual size of the aircraft engine blade. It should be noted that the aircraft engine blade as the experimental research object is installed through a tenon connection structure, which can be either a fan blade or a turbine blade. The first blade specimen 901 and the second blade specimen 902 have the same structure. During the experiment, they are installed on two opposite sides of the mortise and tenon specimen 903 in the horizontal direction. The upper and lower ends of the mortise and tenon specimen 903 are connected by the upper connector 110 and the lower connector 120 of the vertical loading device, respectively. The vertical loading device can use a conventional driving device (such as a hydraulic cylinder, etc.) to make the upper connector 110 and the lower connector 120 move relative to each other in the vertical direction. It should be noted that the vertical loading device can be configured so that only one of the upper connector 110 and the lower connector 120 can move vertically, or it can be configured so that both the upper connector 110 and the lower connector 120 can move vertically, as long as the two can achieve relative movement. The upper connector 110 and the lower connector 120 move away from each other in the vertical direction to apply vertical tension to the mortise and tenon specimen 903, that is, the vertical loading device outputs a vertical load to achieve tension loading on the mortise and tenon specimen 903, simulating the expansion and deformation of the mortise when the engine is actually working.

[0050] The blade specimen and the mortise and tenon specimen 903 form a mortise connection structure, which is used to simulate the micro-motion state formed on the contact surface between the tenon and the tenon after being subjected to complex loads. The horizontal loading device symmetrically outputs horizontal loads to achieve tensile loading on the root of the blade specimen, which is used to simulate the centrifugal load that the blade is subjected to during operation. The horizontal loading device can use a conventional driving device (such as a hydraulic cylinder, etc.) to make the first connector 210 and the second connector move relative to each other in the horizontal direction. Since the horizontal load must be output symmetrically, the horizontal loading device should be configured so that both the first connector 210 and the second connector can move in the horizontal direction. The vibration loading device outputs a disturbance load on the blade specimen in the vertical direction to simulate the vibration load generated by airflow disturbance. The vibrator of the vibration loading device can be of a conventional type as needed.

[0051] The system of the present application not only includes a horizontal loading device capable of outputting horizontal loads to simulate the centrifugal loads that the blades are subjected to during operation, but also includes a vertical loading device capable of outputting vertical loads to simulate the expansion and deformation of the mortise and tenon when the engine is actually working, and a vibration loading device capable of outputting disturbance loads in the vertical direction to simulate the vibration loads generated by airflow disturbances. Therefore, the experimental system provided by the present application can well simulate the actual stress environment of the blades, making it easier to carry out relevant research work on aircraft engine blades.

[0052] In some embodiments, the horizontal loading device may include: a first screw group for carrying the first connector 210, the first screw group includes two first screws 241 arranged at the same height and parallel to each other, and the first connector 210 is threadedly connected to the two first screws 241; a second screw group for carrying the second connector, the second screw group includes two second screws 242 arranged at the same height and parallel to each other, and the second connector is threadedly connected to the two second screws 242. In this embodiment, the first connector 210 and the second connector are driven by their respective corresponding two screws, that is, the two first screws 241 rotate simultaneously to enable the first connector 210 to move, and the two second screws 242 rotate simultaneously to enable the second connector to move. Such a configuration can make the movement of the first connector 210 and the second connector more stable, and a larger driving force can be generated by the two screws to meet the experimental requirements for horizontal tension.

[0053] In some embodiments, the first lead screw 241 and the corresponding second lead screw 242 can be coaxially arranged and connected to the same first support seat 251 at one end close to each other, and the first lead screw 241 and the second lead screw are respectively rotatably connected to the first support seat 251. In this embodiment, the first support seat 251 provides support for the first lead screw 241 and the second lead screw 242 at the same time, which can simplify the structure, reduce the overall occupied volume of the horizontal loading device, and facilitate the horizontal loading device to symmetrically output the horizontal tension. In some embodiments, the horizontal loading device may include: a second support seat 252, located at the end of the first lead screw 241 away from the first support seat 251, and rotatably connected to the two first lead screws 241; a third support seat 253, located at the end of the second lead screw 242 away from the first support seat 251, and rotatably connected to the two second lead screws 242; a horizontally arranged connecting rod 260, connecting the second support seat 252 and the third support seat 253. The two ends of the connecting rod 260 are respectively fixedly connected to the second support seat 252 and the third support seat 253 to form a closed force system, so that the horizontal loading device can more reliably output the horizontal tension. Figure 2 The connecting rod 260 can be provided in two numbers, which are located outside the first screw group and the second screw group, so as to form a more stable closed force system.

[0054] In some embodiments, a drive motor 220 may be configured separately for each lead screw, and the drive motor 220 is used to provide power for the first connector 210 and the second connector to move relative to each other in the horizontal direction. In this embodiment, four drive motors 220 are provided, two of which are used to drive the first lead screw 241 to move the first connector 210 horizontally, and the other two are used to drive the second lead screw 242 to move the second connector horizontally. In some embodiments, the drive motor 220 can be connected to the lead screw through a reducer 270 and a coupling 280, so as to provide a greater driving force and meet the experimental demand for a greater horizontal pulling force.

[0055] In some embodiments, the upper connector 110 may include an inverted U-shaped first holder 111 for connecting to the upper end of the mortise and tenon specimen 903. The first holder 111 may be provided with a plurality of first connection holes for passing a first bolt, and the first bolt horizontally passes through a first through hole provided at the upper end of the mortise and tenon specimen 903. The lower connector 120 may include a U-shaped second holder 121 for connecting to the lower end of the mortise and tenon specimen 903. The second holder 121 may be provided with a plurality of second connection holes for passing a second bolt, and the second bolt horizontally passes through a second through hole provided at the lower end of the mortise and tenon specimen 903. In this embodiment, the upper connector 110 and the lower connector 120 are connected to the mortise and tenon specimen 903 via a U-shaped holder and bolts, as shown in FIG. Figure 1As shown, five first through holes can be set at the upper end of the mortise and tenon test piece 903, and the inverted U-shaped first holder 111 is put on the upper end of the mortise and tenon test piece 903, and the two sides of the first holder 111 ( Figure 1 One side is shown, and the other side is not visible in the figure) and five first connection holes corresponding to the positions of the first through holes are set, and the first bolts horizontally pass through the first through holes on both sides of the first holder 111. Five second through holes can be set at the lower end of the mortise and tenon test piece 903, and the U-shaped second holder 121 is put on the lower end of the mortise and tenon test piece 903, and the two sides of the second holder 121 ( Figure 1 One side is shown, and the other side is not visible in the figure) and five second connection holes corresponding to the positions of the second through holes are arranged, and the second bolts horizontally pass through the second through holes on both sides of the second holder 121. Of course, in other embodiments, the number of the first through holes and the second through holes can be set to other values, for example, to three or four. The above-mentioned connection method between the upper connector 110 and the lower connector 120 and the mortise and tenon specimen 903 can make the vertical loading device more reliably output the vertical direction load to the mortise and tenon specimen 903, meeting the experimental requirements for the expansion and deformation of the mortise and tenon.

[0056] In some embodiments, the vibrator may include an armature 323, an iron core 321 and a coil 322. The vibration loading device may include a frequency converter 360 electrically connected to the coil 322 and a vibration base 310 fixedly connected to the iron core 321. The iron core 321 is located on the top of the vibration base 310, and the armature 323 is connected to the third connector 330. The vibration base 310 is fixed to the ground, and the coil 322 is arranged on the iron core 321. When the coil 322 is passed through the alternating current output by the frequency converter 360, the armature 323 generates a vibration force with a certain frequency and amplitude. In some embodiments, the input and output ends of the frequency converter 360 may be connected to a filter and a reactor. The filter is used to filter out harmonic currents and suppress electromagnetic interference, and the reactor is used to suppress harmonic currents and limit short-circuit currents. Figure 1 As shown, 220V AC is connected to the input end of the input inductor 340. After current limiting and harmonic suppression, the output end of the input inductor 340 is connected to the input end of the input filter 350. After filtering out high-frequency noise and suppressing harmonics again, its output end is connected to the input end of the frequency converter 360. The frequency converter 360 can convert 50 Hz AC to 25 Hz~100 Hz to meet the disturbance load requirements of different frequencies. The output end of the frequency converter 360 is connected to the output filter 370, and is connected to the output inductor 380 after smoothing the output waveform. After the voltage peak is reduced, it is connected to the coil 322. After the coil 322 is connected to AC, the iron core 321 and the armature 323 are magnetized to form an electromagnetic field. The magnetic field of the electromagnet changes with the waveform of the voltage, thereby generating a vibration load with a sinusoidal waveform.

[0057] In some embodiments, the system may include: a data acquisition card 700, electrically connected to the host computer 800; a force sensor 410, installed on the first connector 210 and the second connector, electrically connected to the data acquisition card 700 via a signal amplifier 510; a dynamic force sensor 420, installed on the third connector 330, electrically connected to the data acquisition card 700 via a signal conditioner 520. On this basis, the system may include a motor driver 230, which is electrically connected to the drive motor 220 and the data acquisition card 700, and is used to receive the pulse frequency sent by the data acquisition card 700 to adjust the output torque of the drive motor 220. The host computer 800 is used to process the data collected by the data acquisition card 700 on the one hand, and on the other hand, controls the data acquisition card 700 to output multiple control signals to control the device as a whole, for example, outputs one analog signal and two digital signals to control the motor driver 230, and outputs one digital signal and one analog signal to control the frequency converter 360. The host computer 800 controls the forward and reverse rotation and enabling of the drive motor 220 by outputting two digital signals. The host computer 800 collects the signal of the force sensor 410 amplified by the signal amplifier 510, adjusts the analog pulse signal output to the motor driver 230 in real time, and adjusts the motor output torque to control the horizontal load. In addition, the host computer 800 controls the enabling of the frequency converter 360 by outputting one digital signal, and adjusts the frequency of the vibration load applied by the vibration loading device by outputting one analog signal.

[0058] It should be noted that the principle of arranging the force sensor 410 for measuring the horizontal load in the first connecting body 210 and the second connecting body is the same. Therefore, for the sake of convenience, the following description will only take the case of the first connecting body 210 as an example. Figure 1 and Figure 2 The fixture 211 is connected to the first blade specimen 901, the end face of the force sensor 410 is connected to the back side of the first connector 210, that is, the side facing away from the fixture 211, by bolts, and the extended screw of the force sensor 410 is connected to the thread of the fixture 211, so that the load can be borne and measured, and the millivolt signal outputted by the force sensor 410 is transmitted to the data acquisition card 700 through the signal amplifier 510. The host computer 800 obtains the load signal inputted by the data acquisition card 700, and uses it as feedback to control the pulse frequency outputted by the data acquisition card 700 to the motor driver 230, thereby adjusting the output torque of the motor and realizing precise control of the output load.

[0059] In some embodiments, the system may include a high-speed camera 610, which is used to continuously take pictures of the loaded specimen and transmit the pictures to the host computer 800. On this basis, in order to provide sufficient brightness to take clearer pictures, the system may include an illumination device 620. When performing optical measurement, the illumination device 620 is installed in a suitable position so that the center of the light source is at the same height as the specimen to provide sufficient brightness for the specimen. In digital image processing technology, random speckles are generally sprayed on the surface of the specimen to increase the texture and feature points on the surface of the specimen and ensure that the camera captures a feature image with strong contrast. Therefore, random speckles can be sprayed on the blade specimen to ensure that there are enough feature points on the surface of the blade specimen. Spraying speckles can be spraying a black and white paint on the surface of the blade specimen to create a regular texture structure on the surface of the blade specimen, which can significantly increase the available feature points in the image. The high-speed camera 610 is installed in the upper front of the blade specimen, and the frame rate can be set to 1000 fps. The high-speed camera 610 continuously shoots the blade specimen sprayed with speckles. At the same time, the image data obtained by the high-speed camera 610 is input into the host computer 800 via the network cable, and the host computer 800 quickly calculates the deformation, strain and other parameters of the blade specimen.

[0060] Based on the system for blade micro-motion fatigue test provided by the present application, the present application also provides a method for blade micro-motion fatigue test, the method comprising the following steps: taking the mortise and tenon specimen 903, the first blade specimen 901 and the second blade specimen 902, installing the mortise and tenon specimen 903 to the vertical loading device and fixedly connecting it to the upper connector 110 and the lower connector 120, installing the first blade specimen 901 and the second blade specimen 902 horizontally to the mortise and tenon specimen 903 respectively, and fixing them to the first connector 210 and the second connector of the horizontal loading device respectively, and installing the first blade specimen 901 and the second blade specimen 902 to the first connector 210 and the second connector of the horizontal loading device respectively, and fixing ...901 and the second blade specimen 902 to the first connector 901 and the second blade specimen 902 to the first The three connectors 330 are installed to the first blade specimen 901 or the second blade specimen 902 and fixedly connected. Then, the upper connector 110 and the lower connector 120 move away from each other in the vertical direction to apply vertical tension to the mortise and tenon specimen 903. The first connector 210 and the second connector move away from each other in the horizontal direction to apply horizontal tension to the first blade specimen 901 and the second blade specimen 902. The vibrator of the vibration loading device generates a vertical vibration load and transmits it to the first blade specimen 901 or the second blade specimen 902 connected to the third connector 330 through the third connector 330.

[0061] exist Figure 1 In the exemplary embodiment, the vibration loading device can apply a disturbance load only to the second blade specimen 902. In other embodiments, both the first blade specimen 901 and the second blade specimen 902 can be equipped with a vibration loading device, so that a disturbance load is applied to both blade specimens during the experiment.

[0062] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0063] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. The present invention will not be limited to the embodiments shown herein, but should be consistent with the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for blade micro-fatigue test, characterized in that: include: A vertical loading device, comprising an upper connector connected to the upper end of the mortise and tenon specimen and a lower connector connected to the lower end of the mortise and tenon specimen, wherein the upper connector and the lower connector are capable of relative vertical movement to apply a vertical tensile force to the mortise and tenon specimen to expand and deform the mortise and tenon specimen; A horizontal loading device, comprising a first connector connected to an end of the first blade specimen away from the tenon and a second connector connected to an end of the second blade specimen away from the tenon, wherein the first connector and the second connector are capable of relative movement in a horizontal direction to apply a horizontal tensile force to the first blade specimen and the second blade specimen connected to the tenon-groove specimen; The vibration loading device includes a third connector connected to the blade body of the first blade specimen or the second blade specimen and a vibrator connected to the third connector, and the vertical vibration load generated by the vibrator is transmitted to the first blade specimen or the second blade specimen through the third connector.

2. The system according to claim 1, characterized in that The horizontal loading device comprises: A first screw group for carrying the first connecting body, the first screw group comprising two first screws arranged at the same height and parallel to each other, the first connecting body being threadedly connected to the two first screws; The second screw group is used for carrying the second connecting body, wherein the second screw group includes two second screws which are arranged at the same height and parallel to each other, and the second connecting body is threadedly connected to the two second screws.

3. The system according to claim 2, characterized in that The first screw and the corresponding second screw are coaxially arranged and one end close to each other is connected to the same first support seat, and the first screw and the second screw are respectively rotatably connected to the first support seat.

4. The system according to claim 3, characterized in that The horizontal loading device comprises: A second support seat, located at one end of the first lead screw away from the first support seat, and rotatably connected to the two first lead screws; A third support seat, located at one end of the second lead screw away from the first support seat, and rotatably connected to the two second lead screws; A horizontally arranged connecting rod connects the second supporting seat and the third supporting seat.

5. The system according to claim 1, characterized in that The upper connector includes an inverted U-shaped first holder for connecting to the upper end of the mortise and tenon specimen, the first holder is provided with a plurality of first connection holes for passing first bolts, and the first bolts horizontally pass through first through holes provided at the upper end of the mortise and tenon specimen; The lower connector includes a U-shaped second holder for connecting to the lower end of the mortise and tenon specimen, the second holder is provided with a plurality of second connection holes for passing second bolts, and the second bolts horizontally pass through the second through holes provided at the lower end of the mortise and tenon specimen.

6. The system according to claim 1, characterized in that The vibrator includes an armature, an iron core and a coil, wherein the armature is connected to the third connector, and the vibration loading device includes a frequency converter electrically connected to the coil and a vibration base fixedly connected to the iron core, wherein the iron core is located on the top of the vibration base.

7. The system according to any one of claims 1 to 6, characterized in that: include: Data acquisition card, electrically connected to the host computer; A force sensor, mounted on the first connector and the second connector, and electrically connected to the data acquisition card via a signal amplifier; The dynamic force sensor is installed on the third connector and is electrically connected to the data acquisition card via a signal conditioner.

8. The system according to claim 7, characterized in that A high-speed camera is included for continuously taking photos of the loaded test piece and transmitting the photos to the host computer.

9. The system according to claim 8, characterized in that include: A driving motor, used to provide power for the first connecting body and the second connecting body to move relative to each other in a horizontal direction; The motor driver is electrically connected to the driving motor and the data acquisition card, and is used to receive the pulse frequency sent by the data acquisition card to adjust the output torque of the driving motor.

10. A method for blade fretting fatigue test, using the system for blade fretting fatigue test according to any one of claims 1 to 9, the method comprising: Take the mortise and tenon specimen, the first blade specimen, and the second blade specimen; The mortise and tenon test piece is mounted on the vertical loading device and fixedly connected to the upper connector and the lower connector; The first blade specimen and the second blade specimen are respectively horizontally mounted on the tongue and groove specimen, and are respectively fixedly connected to the first connector and the second connector of the horizontal loading device; The third connector of the vibration loading device is installed on the first blade specimen or the second blade specimen and fixedly connected; The upper connector and the lower connector move away from each other in the vertical direction to apply vertical tension to the mortise and tenon specimen, the first connector and the second connector move away from each other in the horizontal direction to apply horizontal tension to the first blade specimen and the second blade specimen, and the vibrator of the vibration loading device generates a vertical vibration load and transmits it to the first blade specimen or the second blade specimen connected to the third connector through the third connector.

Images