CN116358815A - A test bench for testing the vibration characteristics of an integral blisk with a friction damping structure - Google Patents

Abstract

The invention discloses a blisk vibration characteristic test bed with a friction damping structure, which mainly comprises a driving module, an external excitation module, a testing module and a data analysis module; the invention adopts a lacing wire friction damping structure aiming at the design of the blisk, thereby helping to weaken the coupling vibration of the blisk; in order to verify the reliability of non-contact measurement blade tip vibration data, the invention adopts strain gauge measurement to verify the measurement data; in order to study the disc coupling vibration mode, the invention adopts a scanning laser vibration meter and a permanent magnet to realize the vibration mode measurement of each pitch diameter type of the blisk. The invention can test the vibration characteristics of the blisk structure containing the friction damping structure, study the influence of different rotating speeds and frequency exciting forces on the vibration characteristics of the blisk, and provide data reference for the design and engineering application of the blisk vibration damping structure.

Description

A test bench for testing the vibration characteristics of an integral blisk with a friction damping structure

technical field

The invention belongs to the technical field of engineering and technical research and test development, and in particular relates to a test bench for testing the vibration characteristics of an integral blisk with a friction damping structure.

Background technique

With the continuous improvement of the aviation industry's requirements for engine performance, the requirements for the thrust-to-mass ratio of the engine have further increased, and the turbine and compressor blades in the aero-engine have gradually adopted an integral blisk structure. Compared with the traditional split blade disc structure, the integral blisk structure is simple, avoiding the complex blade-disc blade root groove connection structure, reducing engine mass and improving operating efficiency. Although the monolithic blisk structure has lower mass, it is more prone to blisk coupling vibration because there is no blade-disc contact friction and the stiffness of the blade disc is close.

At present, there are various damping and vibration reduction methods applied to the overall blisk vibration reduction, including coating damping, piezoelectric damping and frictional damping. Among them, the coating damping and piezoelectric damping are mostly used to suppress the modal vibration of the specified mode shape, and the wide-frequency vibration suppression effect is limited. Friction damping is a commonly used vibration reduction method in engineering. Compared with coating damping and piezoelectric damping, friction damping has the advantages of mature technology and low cost. Tie bar structure is a common friction damping structure, which has a good effect in the application of blade vibration reduction, and is currently less used in the overall blisk structure.

In order to ensure the safe operation of the blisk structure in the engine block, designers will measure the vibration parameters of the blisk structure and study its vibration characteristics to ensure the reliability of the blisk operation. Blisks are prone to pitch-diameter vibrations, and disk coupling vibration is the dominant type of blisk vibrations. It is necessary to explore the vibration forms of the blisks in each sensitive order. Therefore, it is of great significance to pay attention to the vibration mode changes at different excitation frequencies. The vibration signal measurement usually adopts the blade tip timing method, and the blade tip timing has the problem of undersampling of the vibration signal acquisition. In order to obtain the vibration displacement of the blade disk, methods such as compressed sensing and other reconstructed data are usually required. Therefore, the vibration signal measurement of the blisk structure with friction damping structure under complex operating conditions, and the accurate data of the vibration characteristics can guide the design and manufacture of the blisk, which is conducive to optimizing the design of the blisk structure with a damping structure. And provide data reference for actual blisk design.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a test bench for testing the vibration characteristics of an integral blisk with a friction damping structure. And the adjustment of the motor realizes the simulation of the actual operating environment of the blisk. The measurement and analysis of the vibration characteristics in a complex operating environment provides data reference for the optimal design of the blisk, and verifies the safe operation of the blisk.

In order to achieve the above object, the present invention adopts following technical scheme to realize:

A test bench for testing the vibration characteristics of an integral blisk with a friction damping structure, including a drive module, an external excitation module, a test module, and a data analysis module;

The drive module is used to drive the rotation of the test piece in the test module through an external power supply, so as to provide rotation conditions for the signal measurement of the test piece;

The external excitation module is used to provide periodic excitation force for the test piece in the test module, simulating the airflow excitation force suffered by the whole blisk test piece during operation;

The test module is used to test the overall blisk test piece, and a variety of contact and non-contact sensors are arranged to obtain data signals;

The data analysis module is used to perform data processing on the electrical signals obtained by the measurement of the test module, and analyze and obtain the response characteristics and mode shapes of the overall blisk.

The further improvement of the present invention is that the drive module includes a servo motor, a belt, a hollow main shaft, a first bearing and a second bearing; the servo motor is connected to the main shaft through a belt, and the belt realizes the transmission function from the servo motor to the main shaft, and then the servo motor is used to complete the For the drive of the main shaft and its connecting parts, the first bearing and the second bearing play a supporting role during the rotation of the main shaft.

The further improvement of the present invention is that the test module includes an electric slip ring, an integral blisk, a test bracket, a strain gauge, an eddy current displacement sensor, a rotational speed sensor and a scanning laser vibrometer;

The blisk with tie structure is connected to the hollow main shaft through a key, and a test bracket is arranged around the blisk, and the eddy current displacement sensor and the speed sensor are fixedly installed on the test bracket to realize the non-contact vibration of the blisk Signal measurement; the scanning laser vibrometer is used to scan and measure the vibration displacement of the whole blade disc, obtain the mode shape distribution, and realize the non-contact measurement of the mode shape of the whole blade disc; the vibration strain of the blade bottom of the part of the whole blade disc is large The strain gauge is installed at the position, the measurement signal passes through the hollow main shaft through the wire, the wire is connected to the electric slip ring at the other end of the main shaft, and is transmitted to the data analysis module through the electric slip ring, so as to realize the contact measurement of the vibration signal of the whole blisk.

The further improvement of the present invention is that the overall blisk adopts an integral blisk with a tie structure, and the overall blisk realizes frictional damping effect by adding a tie structure to the blade body, and the tie structure rubs against the blade through the through hole, The vibration energy is dissipated, thereby reducing the overall blisk vibration amplitude and weakening the blisk coupling vibration.

The further improvement of the present invention is that the eddy current displacement sensor and the rotational speed sensor jointly realize the non-contact measurement of the vibration response of the blade tip, the whole blisk is connected to the main shaft through a key, and the rotational speed sensor is arranged above the position of the keyway to realize the measurement of the rotational speed. An eddy current displacement sensor is arranged on the tip of the blade according to a set angle to monitor the displacement of the blade tip of the overall blisk; based on the monitoring signals of the tip displacement of each displacement sensor at different arrangement angles, combined with the analysis of the speed sensor, the vibration characteristics of the overall blisk can be obtained; The vibration displacement d _s of any blade is obtained by joint analysis of the signals of the speed synchronous sensor and the eddy current sensor:

d _s =R×Ω×Δt _s

为转速，由转速传感器测量两次信号时间差t_ref1-t_ref2获得；Δt_s＝t_measured-t_expected为某一叶顶电涡流位移传感测量时间差，t_expected表示假设无振动时传感器期望测量时间；结合叶尖定时算法处理数据能够获得整体叶盘振动特性参数。where R is the blade tip radius,

is the rotational speed, which is obtained by measuring the time difference between the two signals t _ref1 -t _ref2 by the rotational speed sensor; Δt _s = t _measured - t _expected is the time difference measured by the eddy current displacement sensor on a blade tip, and t _expected represents the expected measurement time of the sensor assuming no vibration ; Combined with the blade tip timing algorithm to process the data, the vibration characteristic parameters of the whole blisk can be obtained.

The further improvement of the present invention is that the test bench uses both contact measurement and non-contact measurement to measure the response of the tip of the blisk, wherein the non-contact measurement is obtained through calculation and analysis, and the contact measurement is obtained directly through strain gauges. Measured, the electrical signal measured by the strain gauge is analyzed by the analysis module combined with the finite element calculation and analysis to obtain the vibration characteristics of the overall blade disk; the contact measurement analysis of the strain gauge can obtain the strain as ε _SG and the blade tip displacement y _BTT obtained by the non-contact measurement analysis through the finite Meta-modal analysis obtains the strain-displacement relationship:

According to the finite element model, the conversion coefficient K _mod =y _mod /ε _mod is obtained, which represents the ratio of the blade tip modal displacement y _mod to the strain gauge modal strain ε _mod ;

The blade vibration under small excitation is regarded as linear vibration, and then the actual vibration response and the strain conversion coefficient are approximately equal to the conversion coefficient K _mod of the modal analysis result, so the blade displacement y _BTT with the strain measurement value ε _SG is written as:

y _BTT =K _mod ·ε _SG .

The further improvement of the present invention is that the external excitation module is used to simulate the excited force of the blisk in actual operation, including permanent magnets. By arranging permanent magnets on the test bracket, the permanent magnets are used to magnetize the blisk structure. The excitation realizes the simulation of the periodic excitation force on the blisk.

The further improvement of the present invention is that considering the influence of external excitation on the vibration characteristics, the blisk is subjected to the periodic excitation force from the nozzle in actual operation, and the test bench uses the force of the permanent magnet on the magnetic blisk to simulate The periodic excitation force; the permanent magnets are fixed on the test bracket and evenly arranged on the lower side of the blisk, the number of permanent magnets is Z ₁ , when the speed of the blisk reaches n _s , the blisk is excited Z ₁ n _s times per second , so the frequency of the exciting force on the whole blisk is:

f _e =Z ₁ n _s .

The further improvement of the present invention is that the scanning laser vibrometer can scan and measure the vibration displacement distribution of the whole blade disk to obtain the vibration shape of the whole blade disk; according to the relationship between the frequency of the exciting force, the number of permanent magnets on the test bracket can be adjusted to realize the overall The frequency of the excited vibration of the blisk is adjusted; the permanent magnet is adjusted to change the frequency of the excited vibration of the blisk, and the scanning laser vibrometer further measures the mode shape of each pitch.

Compared with the prior art, the present invention has at least the following beneficial technical effects:

The present invention provides a test bench for testing the vibration characteristics of an integral blisk with a friction damping structure. The blisk coupling vibration can further ensure the operation reliability of the blisk as a whole. In the present invention, both non-contact measurement and contact measurement methods are used to test and analyze the vibration characteristics of the overall blisk, and the contact measurement is used to verify the non-contact measurement results to ensure the validity and accuracy of the measurement results. In addition, the present invention uses a magnetic excitation method to simulate the airflow excitation force received by the blisk during operation, and can adjust the frequency of the excited vibration force on the blisk by adjusting the number of permanent magnets arranged, and then use a scanning laser vibrometer to measure the overall blisk. The mode shapes of the blisk with different pitch diameters. The invention can test the vibration characteristics of the blisk structure with a friction damping structure, study the influence of different rotating speeds and frequency excitation forces on the vibration characteristics of the blisk, provide data reference for the design of the blisk vibration damping structure and help guide engineering applications design.

Description of drawings

Fig. 1 is the schematic diagram of a kind of integrated blisk vibration characteristic test bench that contains frictional damping structure of the present invention;

Fig. 2 is a structural schematic diagram of an integral blisk structure including a frictional damping structure;

Fig. 3 is a structural schematic diagram of an external excitation module and a test module;

Figure 4 is a schematic diagram of the test bench test method.

Explanation of reference signs:

1. Electric slip ring; 2. Servo motor; 3. Belt; 4. First bearing; 5. Hollow main shaft; 2. Bearing; 11. Eddy current displacement sensor; 12. Speed sensor; 13. Scanning laser vibrometer; 14. Speed sensor mounting frame; 15. Displacement sensor mounting frame; 16. Permanent magnet mounting frame;

Detailed ways

The present invention will be described in further detail below in conjunction with accompanying drawing and specific embodiment:

Please refer to Fig. 1, a test bench for analyzing the vibration characteristics of a blisk with a frictional damping structure provided by the present invention, a tension structure is added to the blisk to reduce the blisk coupling vibration of the blisk, and the contact and Non-contact measurement of the vibration characteristics of the blisk under the action of rotational speed and magnetic excitation. The test bench mainly includes a drive module, an external stimulus module, a test module and a data analysis module.

Wherein, the driving module mainly includes a servo motor 2 , a belt 3 , a first bearing 4 , a hollow main shaft 5 and a second bearing 10 . The servo motor 2 is connected to the hollow main shaft 5 through the belt 3, the transmission from the servo motor 2 to the hollow main shaft 5 is realized through the belt 3, and then the servo motor 2 is used to complete the driving function for the main shaft 5 and its connecting parts, the first bearing 4 and the second The second bearing 10 plays a supporting role for the hollow main shaft 5 during rotation.

Among them, the test module mainly includes an electric slip ring 1 , an integral blisk 6 , a strain gauge 7 , a test stand 9 , an eddy current displacement sensor 11 , a rotational speed sensor 12 and a scanning laser vibrometer 13 . The overall blisk 6 with the tie structure is connected to the hollow main shaft 5 through a key, and a test bracket 9 is arranged on the periphery of the overall blisk, the eddy current displacement sensor 11 is fixedly installed on the test bracket 9, and the speed sensor 12 is also arranged on the test bracket 9, used to realize the non-contact vibration signal measurement of the blisk 6. At the same time, the scanning laser vibrometer 13 can scan and measure the vibration displacement of the blisk 6 to obtain the mode shape distribution, and realize the non-contact measurement of the mode shape of the blisk 6 . In addition, a strain gauge 7 is installed at the bottom of the blade of the blisk, the measurement signal passes through the hollow main shaft 5 through the wire, the wire is connected to the electric slip ring 1 at the other end, and is transmitted to the data analysis module through the electric slip ring 1, realizing the overall Contact measurement of blisk vibration signals.

Wherein, the external excitation module mainly includes a test bracket 9 and a permanent magnet 10 . The external excitation module is used to simulate the excited vibration force of the blisk 6. By arranging the permanent magnet 10 on the test bracket 9, the permanent magnet 10 is used to magnetically excite the blisk 6 to realize the periodic excitation of the blisk 6. Vibration simulation;

Please refer to Fig. 2, a blisk with a friction damping structure according to the present invention mainly includes a blisk 6 and a tie bar 16, and the blisk realizes frictional damping by adding a tie structure to the blade body of the blisk 6 During the vibration process, the tension structure realizes the vibration energy dissipation through the mutual friction between the blade and the blade, thereby helping to reduce the coupled vibration of the blisk and improving the operation reliability of the overall blisk.

Please refer to Fig. 3, external excitation module and test module structure of the present invention, eddy current displacement sensor 11 is fixed to test support 9 by displacement sensor mounting frame 15, and rotational speed sensor 12 is fixed to test support 9 by rotational speed sensor mounting frame 14, permanent magnet 8 is fixed to the test stand 9 by a magnet mount 16. The rotation speed sensor 12 is arranged above the key connection between the blisk 6 and the hollow main shaft 5 to realize the measurement of the rotation speed. A plurality of eddy current displacement sensors 11 monitor signals based on different arrangement angles, combined with the analysis of the rotation speed sensor 12, the vibration characteristics of the whole blisk can be obtained. The vibration displacement d _s of any blade can be obtained through joint analysis of the signals of the rotational speed sensor 12 and the eddy current sensor 11:

d _s =R×Ω×Δt _s

为转速，由转速传感器12测量两次信号时间差t_ref1-t_ref2获得。Δt_s＝t_measured-t_expected为某一叶顶电涡流位移传感11器测量时间差，t_expected表示假设无振动时传感器期望测量时间。进一步地结合叶尖定时算法处理数据可以获得整体叶盘振动特性参数。where R is the blade tip radius,

is the rotational speed, which is obtained by measuring the time difference t _ref1 -t _ref2 between two signals measured by the rotational speed sensor 12 . Δt _s =t _measured −t _expected is the measurement time difference of a blade tip eddy current displacement sensor 11, and t _expected represents the expected measurement time of the sensor assuming no vibration. The vibration characteristic parameters of the overall blisk can be obtained by further combining the blade tip timing algorithm to process the data.

The contact measurement method is directly measured by the strain gauge 7. The strain gauge 7 is installed in the high strain area near the bottom. The electrical signal measured by the strain gauge 7 can be calculated by the analysis module to obtain the vibration displacement of the blade top of the overall blade disk 6 for verification. Non-contact measurement. The contact measurement strain of strain gauge 7 is ε _SG and the blade tip displacement y _BTT obtained by non-contact measurement analysis can obtain the relationship between strain and displacement through finite element modal analysis:

According to the finite element model, the conversion coefficient K _mod =y _mod /ε _mod can be obtained, and the conversion coefficient represents the ratio of the modal displacement y _mod of the blade tip to the modal strain ε _mod of the strain gauge.

The blade vibration under small excitation can be regarded as linear vibration, and then the actual vibration response and the strain conversion coefficient are approximately equal to the conversion coefficient K _mod of the modal analysis results, so the blade displacement y _BTT with the measured strain ε _SG can be written as:

y _BTT ＝K _mod ·ε _SG

The permanent magnet 8 of the present invention is fixed to the test bracket 9 through the magnet mounting frame 16, and is used to simulate the influence of the external exciting force on the vibration characteristics of the blisk. In actual operation, the blisk is subjected to the periodic exciting force from the nozzle. The test bench The periodic excitation force on the blisk 6 is simulated by using the force of the permanent magnet 8 on the blisk 6 . The permanent magnet 8 is fixed on the test bracket 9 through the magnet mounting frame 16, and is evenly arranged on the lower side of the blisk 6. The number of permanent magnets 8 is Z ₁ . When the speed of the blisk 6 reaches n _s , the blisk 6 bears Excite Z ₁ n _s times, so the frequency of the exciting force on the blisk 6 is:

f _e =Z ₁ n _s

In the present invention, the scanning laser vibrometer 13 can scan and measure the vibration displacement distribution of the blisk 6 to obtain the mode shape of the blisk 6 . According to the above-mentioned relational expression of the frequency of the excitation force, the frequency adjustment of the frequency of the excitation force to the blisk 6 can be realized by adjusting the number of permanent magnets 8 on the test stand. The scanning laser vibrometer 13 can further measure the mode shapes of the whole blade disk 6 under various pitch diameters by measuring the frequency of the excited vibration force of the whole blade disk 6 .

In order to further understand the test bench for vibration characteristics of an integral blisk with a frictional damping structure and its testing method of the present invention, its operation steps are now described.

The testing process of timing vibration state monitoring of rotating blade tip is as follows:

(1) Install the non-contact sensor: install the eddy current displacement sensor 11 to the preset position corresponding to the test bracket 9 respectively, as the blade tip timing sensor; install the rotational speed sensor 12 at the key position of the rotating shaft; use a DC power supply to the sensor Power supply, output signal to the data collector for setting and debugging;

(2) Install and adjust the overall blisk: mark the number of the blade, and arrange the strain gage 7 in the area with large vibration and strain at the bottom of the blade according to the finite element analysis results; adjust the position height of the eddy current displacement sensor 11 for calibration; set the speed signal through PLC And write it into the motor driver to set the motor speed;

(3) Verify the non-contact measurement results: analyze the measurement signals of the strain gauge 7 through the finite element calculation results, and obtain the vibration displacement response of the blade tip. The signal is obtained through the eddy current displacement sensor 11 and the rotational speed sensor 13, and the vibration displacement response is reconstructed by compressive sensing method, and verified with contact measurement.

(4) Apply exciting force and collect signals: adjust the distribution of permanent magnets 8, apply exciting force to the blisk 6, and simulate the operation of the blisk 6 to withstand the exciting force of the airflow. The blade tip timing method is used to collect blade vibration signals under working conditions, and the scanning laser vibrometer 13 is used to scan and measure the 6 mode shapes of the overall blade disk, and multiple sets of data are collected for the next step of signal processing;

(5) Repeat steps (2) to (4), adjust the motor speed, and obtain blade vibration signals under different operating conditions.

Finally, it should be noted that the above examples are only preferred implementations of the present invention, and are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the above examples, ordinary people in the field The skilled person should understand that: the specific implementation of the present invention can still be modified or equivalently replaced, and any modification or equivalently replaced without departing from the spirit and scope of the present invention shall be covered within the protection scope of the claims of the present invention.

Claims (9)

1. The test bed for testing the vibration characteristics of the blisk with the friction damping structure is characterized by comprising a driving module, an external excitation module, a testing module and a data analysis module;

the driving module is used for driving the test piece in the test module to rotate through an external power supply and providing rotation conditions for signal measurement of the test piece;

the external excitation module is used for providing periodic excitation force for the test piece in the test module and simulating airflow excitation force applied to the blisk test piece in the operation process;

the testing module is used for testing the blisk test piece and arranging various contact type and non-contact type sensors to obtain data signals;

and the data analysis module is used for carrying out data processing on the electric signals obtained by the measurement of the test module and analyzing to obtain the response characteristics and the mode shape of the blisk.

2. The test stand for testing the vibration characteristics of a blisk having a friction damping structure according to claim 1, wherein the drive module comprises a servo motor, a belt, a hollow spindle, a first bearing, and a second bearing; the servo motor is connected to the main shaft through a belt, the belt achieves a transmission function from the servo motor to the main shaft, the main shaft and a connecting component of the main shaft are driven by the servo motor, and the first bearing and the second bearing play a supporting role in the rotation process of the main shaft.

3. The test bench for testing the vibration characteristics of the blisk with the friction damping structure according to claim 1, wherein the test module comprises an electric slip ring, a blisk, a test support, a strain gauge, an eddy current displacement sensor, a rotation speed sensor and a scanning type laser vibration meter;

the blisk with the lacing wire structure is connected to the hollow main shaft through a key, a test bracket is arranged on the periphery of the blisk, and an eddy current displacement sensor and a rotating speed sensor are fixedly arranged on the test bracket and used for realizing the non-contact vibration signal measurement of the blisk; the scanning type laser vibration meter is used for scanning and measuring the vibration displacement of the blisk to obtain vibration mode distribution, and realizing non-contact measurement on the overall She Panmo vibration mode; and a strain gauge is arranged at a large position of the vibration strain of the blade bottom of the blade of the blisk part, a measurement signal passes through the hollow main shaft through a lead, the lead is connected to an electric slip ring at the other end of the main shaft, and the electric slip ring is transmitted to a data analysis module, so that the contact measurement of the blisk vibration signal is realized.

4. The test bed for testing the vibration characteristics of the blisk with the friction damping structure according to claim 3, wherein the blisk is a blisk with a lacing wire structure, the lacing wire structure is added to the blade body to realize the friction damping effect, and the lacing wire structure rubs with the blade through the through hole to dissipate vibration energy, so that the vibration amplitude of the blisk is reduced, and the coupling vibration of the blisk is weakened.

5. A test stand for testing vibration characteristics of a blisk with a friction damping structure according to claim 3, wherein an eddy current displacement sensor and a rotation speed sensor are used for realizing contactless measurement of a response of vibration of a blisk top, the blisk is connected to a main shaft through a key, the rotation speed sensor is arranged above a key slot position to realize measurement of rotation speed, and a plurality of eddy current displacement sensors are arranged at the blisk top according to a set angle to realize detection of displacement of the blisk top; based on displacement monitoring signals of blade tops of the displacement sensors with different arrangement angles, the vibration characteristics of the blisk can be obtained by combining analysis of a rotating speed sensor; displacement d of any blade _s And according to the common analysis of signals of the rotating speed synchronous sensor and the eddy current sensor, obtaining:

d _s ＝R×Ω×Δt _s

wherein R is the radius of the tip of the leaf,

for the rotation speed, the time difference t of the two signals is measured by a rotation speed sensor _ref1 -t _ref2 Obtaining; Δt (delta t) _s ＝t _measured -t _expected For measuring time difference, t, of displacement sensing of eddy current at certain blade top _expected Indicating the expected measurement time of the sensor assuming no vibration; and processing the data by combining a blade tip timing algorithm to obtain the vibration characteristic parameters of the blisk.

6. The test bed for testing the vibration characteristics of the blisk with the friction damping structure according to claim 3, wherein the test bed simultaneously uses a contact type measurement mode and a non-contact type measurement mode to measure the blisk tip response, wherein the non-contact type measurement is obtained through calculation and analysis, the contact type measurement mode is directly measured through a strain gauge, and an electric signal measured by the strain gauge is combined with finite element calculation and analysis through an analysis module to obtain the vibration characteristics of the blisk; strain gauge contact measurement and analysis can obtain strain epsilon _SG Tip displacement y obtained by non-contact measurement and analysis _BTT Obtaining the relation between strain and displacement through finite element modal analysis:

obtaining a conversion coefficient K according to a finite element model _mod ＝y _mod /ε _mod The conversion coefficient represents the tip mode displacement y _mod And strain gage modal strain epsilon _mod Ratio of;

the vibration of the blade under small excitation is regarded as linear vibration, and then the actual vibration response and the strain conversion coefficient are approximately equal to the conversion coefficient K of the modal analysis result _mod Therefore, there is a strain measurement ε _SG Is of the blade displacement y _BTT Writing:

y _BTT ＝K _mod ·ε _SG 。

7. a test stand for testing vibration characteristics of a blisk with a friction damping structure according to claim 3, wherein the external excitation module is used for simulating the excitation force applied to the blisk in actual operation, and comprises a permanent magnet, and the periodic excitation force applied to the blisk is simulated by magnetically exciting the blisk structure by the permanent magnet through arranging the permanent magnet on the test support.

8. The test bed for testing the vibration characteristics of the blisk with the friction damping structure according to claim 7, wherein the test bed simulates the periodic excitation force applied to the blisk by the permanent magnet on the magnetic conductive blisk by taking the influence of external excitation on the vibration characteristics into consideration and applying the periodic excitation force from the nozzle to the blisk in actual operation; the permanent magnets are fixed on the test support and are uniformly arranged on the lower side of the blisk, and the number of the permanent magnets is Z ₁ The rotating speed of the blisk reaches n _s When the blisk is subjected to excitation Z per second ₁ n _s The frequencies of exciting forces received by the blisk are as follows:

f _e ＝Z ₁ n _s 。

9. the test bed for testing the vibration characteristics of the blisk with the friction damping structure according to claim 8, wherein the scanning type laser vibrometer can scan and measure the vibration displacement distribution of the blisk to obtain the blisk vibration pattern; according to the exciting force frequency relation, the exciting force frequency adjustment of the blisk is realized by adjusting the number of permanent magnets on the test bracket; the permanent magnet is adjusted to change the frequency of the exciting force of the blisk, and the scanning type laser vibration meter further measures the mode vibration mode under each pitch diameter mode.

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