Squirrel cage spring support strain test method and aeroengine squirrel cage spring support

Abstract

The present invention discloses a squirrel-cage spring support strain test method, comprising the following steps: S1, according to the structural characteristics and working characteristics of the spring support, finite element analysis is performed on it to determine the appropriate strain measurement point position on the spring bar; S2, according to the strain measurement point position, the appropriate temperature measurement point position is determined on the spring bar; S3, a strain gauge is pasted at the strain measurement point position, and a temperature sensor is pasted at the temperature measurement point position; S4, according to the working boundary conditions of the spring support in the engine, a calibration device is designed, and the calibration device is used to calibrate the "strain-displacement" relationship between the strain at the spring bar strain measurement point and the radial displacement of the free end of the spring support for the spring bar that has been pasted by using a loading calibration method; S5, the spring support is installed in the engine to carry out real-time spring support strain testing during the engine bench test. In addition, a squirrel-cage spring support of an aircraft engine tested by the above-mentioned squirrel-cage spring support strain test method is also disclosed.

Description

Technical Field

[0001] The present invention relates to the technical field of engine testing, and in particular, to a method for testing the strain of a squirrel cage spring support. In addition, the present invention also relates to an aero-engine squirrel cage spring support tested by the squirrel cage spring support strain testing method. Background Art

[0002] The speed of modern aircraft engines is generally above 10,000 rpm, and the operating speed of some small engines is as high as (40,000-50,000) rpm. For such high-speed engines, the structural integrity and reliability issues are very prominent, and the vibration and stability of their rotor-support system are often the crux of the problem. The practice of my country's large and small engine model development and high-performance engine pre-research shows that the vibration failure of the engine caused by the rotor-support system has become a major technical key encountered in development and pre-research.

[0003] Generally, the elastic supports used in aircraft engine rotor systems have very low rigidity relative to the rigidity of the rotor, i.e., low-rigidity elastic supports, which are designed to reduce the critical speed of the rotor system to the required value without weakening the rigidity of the rotor itself, and when passing the critical speed, the amplitude of the rotor and the external load transmitted through the bearing seat are very small. When this type of rotor system passes the low-order rigid body critical speed within the operating speed range, the deformation mainly occurs in the elastic supports, while the shaft basically does not bend or deform, and its deformation can be ignored. When the rotor system passes the bending critical speed, the shaft bends and deforms, and the deformation at its elastic supports is also large.

[0004] During the whole-machine test of an aircraft engine, the rotor is located inside the engine casing. It is difficult to install a general vibration sensor inside the casing to monitor the vibration of the rotor system in real time. However, for a small-engine high-speed rotor system with elastic supports, the vibration of its rotating parts is directly transmitted to the elastic support as a stationary part. If the vibration signal of the rotor can be obtained from the elastic support, it will make the vibration monitoring of the rotor easier to achieve.

[0005] At present, the elastic support structure of aircraft engine rotors mainly includes squirrel cage type, elastic ring type, O-ring type, etc., among which squirrel cage type elastic support is the most common. The squirrel cage type elastic support is composed of a series of cylindrical ribs installed or welded in the flange surface at both ends through threads, or cut grooves along the circumference on a hollow cylinder. One end of the elastic support is fixed on the casing through the flange surface, and the rotor bearing is installed on the inner ring of the free end of the elastic support. The pressure oil is filled in the annular gap between the outer ring of the free end of the elastic support and the casing to provide oil film damping. During the high-speed operation of the rotor, the radial displacement of the journal (free end of the elastic support) will cause the elastic bar to undergo alternating deformation. The elastic support vibration strain test technology adopts the resistance strain electrical measurement method. For the squirrel cage type elastic support, a strain gauge that meets the requirements of size, temperature, etc. is pasted at the maximum stress point of the root of the elastic bar at the vertical and horizontal directions of the elastic support near the installation edge. The vibration strain signal sensed by the strain gauge is drawn out from the small hole on the casing through a special lead, connected to the dynamic resistance strain gauge for measurement, and then the vibration strain signal is recorded and analyzed by the dynamic signal recorder and analyzer. According to the relevant content in the "Aero Engine Design Manual Volume 19 Rotor Dynamics", there is a one-to-one correspondence between the vibration displacement at the rotor journal and the vibration strain on the spring bar. By monitoring the vibration strain signal at the root of the spring bar, the real-time monitoring of the vibration displacement of the engine rotor can be achieved. The magnitude of the alternating strain at the root of the spring bar reflects the magnitude of the rotor journal deflection. Of course, this deformation is limited by the gap between the squeezed oil film.

[0006] The existing elastic support strain test method determines through empirical judgment that the inner surface of the root of the spring bar of all squirrel cage spring supports is the area with the largest vibration strain of the spring bar. For all squirrel cage spring supports, the inner surface of the root of the spring bar is used as the patch point, and the corresponding relationship between the vibration displacement at the rotor shaft neck and the vibration strain on the spring bar is obtained through the empirical formula in the "Rotor Dynamics of the 19th Volume of the Aviation Engine Design Manual". However, in fact, there is a certain deviation between the vibration displacement value at the shaft neck obtained in this way and the actual value. In addition, during the operation of the engine, the ambient temperature of the spring support will increase with the increase of the engine speed, and correspondingly, the elastic modulus of the material of the spring support will decrease accordingly. According to the relevant knowledge of material mechanics, within the range of elastic deformation, the material stress is equal to the product of the material strain and its elastic modulus. However, in the existing elastic support strain test method, it is assumed that the elastic modulus of the spring support material is a constant value within the full speed range of the engine. In this way, the stress value converted according to the strain test result will also have a certain deviation from the actual value, resulting in inaccurate test results. Summary of the invention

[0007] The invention provides a squirrel cage spring support strain testing method and an aero-engine squirrel cage spring support, so as to solve the technical problems that the existing squirrel cage spring support strain testing has deviation and inaccurate test results.

[0008] According to one aspect of the present invention, a method for testing strain of a squirrel-cage spring-loaded support is provided, comprising the following steps: S1, performing finite element analysis on the spring-loaded support according to its structural characteristics and working characteristics, so as to determine a suitable strain measuring point position on the spring-loaded support; S2, determining a suitable temperature measuring point position on the spring-loaded support according to the strain measuring point position; S3, pasting a strain gauge at the strain measuring point position, and pasting a temperature sensor at the temperature measuring point position; S4, designing a calibration device according to the working boundary conditions of the spring-loaded support in the engine, and calibrating the "strain-displacement" relationship between the strain at the strain measuring point of the spring-loaded support and the radial displacement of the free end of the spring-loaded support by the calibration device through a loading calibration method; S5, installing the spring-loaded support in the engine, so as to carry out real-time spring-loaded support strain testing during the engine bench test.

[0009] As a further improvement of the above technical solution:

[0010] Furthermore, step S1 specifically includes the following steps: according to the structural characteristics and working characteristics of the elastic support, the deformation characteristics of the elastic support in the working state are analyzed, mainly analyzing the strain distribution characteristics at each point on the elastic bar when the elastic bar is deformed due to the radial displacement at the rotor journal, so as to determine the strain measurement point position of the elastic bar in the area with suitable strain distribution characteristics.

[0011] Furthermore, suitable strain distribution characteristics refer to having both "relatively gentle strain change gradient" and "large relative strain level" characteristics.

[0012] Further, step S2 specifically includes the following steps: according to the position of the strain measuring point on the elastic bar, determine the same position on the other elastic bars that is in the same circular cross section as the strain measuring point position as the temperature measuring point position.

[0013] Furthermore, step S4 specifically includes the following steps: designing a calibration device according to the working boundary conditions of the elastic support in the engine, the calibration device rigidly fixes the installation edge of the elastic support by simulating the actual state, so that the installation edge after fixation is completely constrained, and then within the elastic deformation range of the elastic support, successively applying a radial load of a certain magnitude in the vertical direction and the horizontal direction of the free end of the elastic support, and measuring the strain value at each strain measuring point on the elastic bar and the radial displacement value of the free end of the elastic support at the same time, so as to obtain the corresponding relationship between the strain at the elastic bar measuring point and the radial displacement of the free end of the elastic support.

[0014] Furthermore, the calibration device includes a mounting seat, a mounting plate for fixing the mounting edge of the spring support on the mounting seat, a loading ring for sleeved on the outer wall of the spring support, a loading rod connected to the loading ring for applying a radial load, a displacement sensor connected to the loading ring for measuring radial displacement, and a strain gauge for measuring strain at the strain measuring point.

[0015] Further, in step S5, the strain test of the elastic support specifically includes the following steps: measuring the strain and temperature value of the elastic bar in real time during the operation of the engine by means of a strain gauge and a temperature sensor, obtaining the real-time radial displacement change of the free end of the elastic support according to the "strain-displacement" relationship and the real-time strain of the elastic bar, determining the real-time elastic modulus of the elastic bar material according to the real-time temperature value of the elastic bar, and then obtaining the real-time elastic bar stress value according to the real-time elastic modulus of the elastic bar material and the real-time strain of the elastic bar, and realizing real-time safety monitoring of the rotor during the engine test and obtaining accurate imbalance response value at the rotor journal according to the real-time radial displacement change of the free end of the elastic support and the real-time elastic bar stress value.

[0016] Furthermore, step S3 specifically includes the following steps: according to the working boundary conditions of the spring support in the engine and the parameter information of the parts material, selecting appropriate strain gauges, temperature sensors and corresponding pasting work, so as to paste the strain gauges at the strain measuring point positions and paste the temperature sensors at the temperature measuring point positions.

[0017] Furthermore, the working boundary conditions include working temperature and oil resistance.

[0018] According to another aspect of the present invention, there is also provided an aircraft engine squirrel cage spring support, which includes the above-mentioned squirrel cage spring support strain testing method.

[0019] The present invention has the following beneficial effects:

[0020] The squirrel cage spring support strain testing method of the present invention performs finite element analysis on the spring support according to its structural characteristics and working characteristics, so as to determine a suitable strain measuring point position on the spring bar, ensure that the strain measuring point is the area with the largest vibration strain of the spring bar, eliminate the deviation caused by inaccurate selection of the strain measuring point, and improve the test accuracy of subsequent strain testing; then determine a suitable temperature measuring point position on the spring bar according to the strain measuring point position, so as to perform real-time spring bar strain measurement in the subsequent testing process, and simultaneously perform real-time spring bar temperature value measurement, thereby obtaining real-time elastic modulus of the spring bar material, thereby obtaining real-time spring bar stress value, eliminating the deviation of the spring bar stress value caused by temperature change, and improving the test accuracy of subsequent strain testing; then paste a strain gauge at the strain measuring point position to obtain real-time spring bar strain during the actual testing process, and paste a temperature sensor at the temperature measuring point position to obtain real-time spring bar temperature value during the actual testing process; design a calibration device according to the working boundary conditions of the spring support in the engine, and use the calibration device to calibrate the spring bar after pasting by loading calibration. The "strain-displacement" relationship between the strain at the elastic deformation measuring point of the elastic support and the radial displacement of the free end of the elastic support is calibrated to accurately obtain the corresponding relationship between the strain at the measuring point of the elastic support and the radial displacement of the free end of the elastic support, which provides a strong guarantee for the subsequent accurate and real-time radial displacement change of the free end of the elastic support; finally, the elastic support is installed in the engine to carry out real-time elastic support strain testing during the engine bench test. During the elastic support strain testing, the real-time safety monitoring of the rotor during the engine test and the accurate imbalance response value of the rotor journal are achieved according to the real-time elastic bar stress value and the real-time radial displacement change of the free end of the elastic support; compared with the existing technology, the determination of the strain measuring point of this scheme is no longer based on empirical judgment, and the influence of temperature change on the elastic modulus of the elastic bar material is taken into account. Then, the "strain-displacement" relationship of the elastic support is calibrated in advance through the labeling device, which is beneficial to ensure the real-time testing of the elastic support strain and the accurate interpretation of the test results during the subsequent engine test, and significantly improves the test accuracy of the elastic bar stress value and the radial displacement change of the free end of the elastic support.

[0021] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 It is a flowchart of the steps of the squirrel cage spring support strain testing method according to the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0025] Figure 1 It is a flowchart of the steps of the squirrel cage spring support strain testing method according to the preferred embodiment of the present invention.

[0026] like Figure 1As shown, the squirrel cage spring support strain testing method of this embodiment includes the following steps: S1, according to the structural characteristics and working characteristics of the spring support, a finite element analysis is performed on it to determine the appropriate strain measuring point position on the spring bar; S2, according to the strain measuring point position, a suitable temperature measuring point position is determined on the spring bar; S3, a strain gauge is pasted at the strain measuring point position, and a temperature sensor is pasted at the temperature measuring point position; S4, according to the working boundary conditions of the spring support in the engine, a calibration device is designed, and the "strain-displacement" relationship between the strain at the strain measuring point of the spring bar and the radial displacement of the free end of the spring support is calibrated by the calibration device through loading calibration; S5, the spring support is installed in the engine to carry out real-time spring support strain testing during the engine bench test. Specifically, the squirrel cage spring support strain testing method of the present invention performs finite element analysis on the spring support according to its structural characteristics and working characteristics, so as to determine the appropriate strain measurement point position on the spring bar, ensure that the strain measurement point is the area with the largest vibration strain of the spring bar, eliminate the deviation caused by inaccurate strain measurement point selection, and improve the test accuracy of subsequent strain tests; then determine the appropriate temperature measurement point position on the spring bar according to the strain measurement point position, so as to perform real-time spring bar strain measurement in the subsequent test process, and simultaneously perform real-time spring bar temperature value measurement, thereby obtaining the real-time elastic modulus of the spring bar material, thereby obtaining the real-time spring bar stress value, eliminating the deviation of the spring bar stress value caused by temperature change, and improving the test accuracy of subsequent strain tests; then paste the strain gauge at the strain measurement point position to obtain the real-time spring bar strain during the actual test process, and paste the temperature sensor at the temperature measurement point position to obtain the real-time spring bar temperature value during the actual test process; design a calibration device according to the working boundary conditions of the spring support in the engine, and use the calibration device to load and calibrate the pasted spring bar material by the calibration device. The elastic strip is calibrated to calibrate the "strain-displacement" relationship between the strain at the elastic deformation measuring point of the elastic strip and the radial displacement of the free end of the elastic strip, so as to accurately obtain the corresponding relationship between the strain at the measuring point of the elastic strip and the radial displacement of the free end of the elastic strip, and provide a strong guarantee for the subsequent accurate acquisition of the real-time radial displacement change of the free end of the elastic strip; finally, the elastic strip is installed in the engine to carry out real-time elastic strip strain testing during the engine bench test. During the elastic strip strain testing, the real-time safety monitoring of the rotor during the engine test and the accurate imbalance response value of the rotor journal are achieved according to the real-time elastic strip stress value and the real-time radial displacement change of the free end of the elastic strip; compared with the prior art, the determination of the strain measuring point of this scheme is no longer based on empirical judgment, and the influence of temperature change on the elastic modulus of the elastic strip material is taken into account. Then, the "strain-displacement" relationship of the elastic strip is calibrated in advance by a labeling device, which is beneficial to ensure the real-time testing of the elastic strip strain and the accurate interpretation of the test results during the subsequent engine test, and significantly improves the test accuracy of the elastic strip stress value and the radial displacement change of the free end of the elastic strip.Optionally, the finite element analysis software is selected from Ansys, Abaqus, etc. It should be understood that the elastic support includes an annular mounting edge, an annular free end coaxially arranged with the annular mounting edge, and a plurality of elastic bars circumferentially spaced between the annular mounting edge and the annular free end.

[0027] In this embodiment, step S1 specifically includes the following steps: according to the structural characteristics and working characteristics of the elastic support, the deformation characteristics of the elastic support in the working state are analyzed, and the strain distribution characteristics at each point on the elastic bar when the elastic bar is deformed due to the radial displacement at the rotor shaft neck are mainly analyzed, so as to determine the position of the strain measurement point of the elastic bar in the area with suitable strain distribution characteristics. Specifically, by analyzing the strain distribution characteristics at each point on the elastic bar when the elastic bar is deformed due to the radial displacement at the rotor shaft neck, the strain measurement point is determined according to the strain distribution characteristics, thereby avoiding the error that may be caused by selecting the strain measurement point based on experience judgment, and improving the strain test accuracy.

[0028] In this embodiment, the suitable strain distribution characteristics refer to having both the characteristics of "relatively slow strain change gradient" and "relatively large relative strain level". Specifically, when the strain measuring point is located in an area having both the characteristics of "relatively slow strain change gradient" and "relatively large relative strain level", in the subsequent testing process of the strain condition of the spring bar measuring point, higher strain test accuracy and better signal-to-noise ratio can be ensured.

[0029] In this embodiment, step S2 specifically includes the following steps: according to the position of the strain measuring point on the elastic bar, the same position on the other elastic bars that is in the same circumferential cross section as the strain measuring point position is determined as the temperature measuring point position. Specifically, the temperature measurement can be performed synchronously while the strain measurement of the elastic support is performed within the full speed range of the engine through the temperature measuring point, so as to determine the real-time elastic modulus of the elastic bar material. Optionally, two strain measuring points are determined along the vertical direction of the elastic support, and two strain measuring points are determined along the horizontal direction of the elastic support. The strain conditions of multiple elastic bar measuring points are obtained by measuring multiple strain measuring points to improve the strain test accuracy. Optionally, multiple temperature measuring points are arranged at intervals along the circumference of the elastic support, and multiple elastic moduli of elastic bar materials are obtained by multiple temperature measuring points to improve the test accuracy of the stress value of the elastic bar. It should be understood that the elastic support includes multiple elastic bars arranged at intervals along the circumference, and the circumferential cross section of the multiple elastic bars is annular.

[0030] In this embodiment, step S4 specifically includes the following steps: designing a calibration device according to the working boundary conditions of the elastic support in the engine, the calibration device rigidly fixes the installation edge of the elastic support by simulating the actual state, so that the installation edge after fixation is completely constrained, and then within the elastic deformation range of the elastic support, successively applying a certain magnitude of radial load to the vertical direction and the horizontal direction of the free end of the elastic support, and measuring the strain value at each strain measuring point on the elastic bar and the radial displacement value of the free end of the elastic support at the same time, so as to obtain the corresponding relationship between the strain at the elastic bar measuring point and the radial displacement of the free end of the elastic support. Specifically, the corresponding relationship between the strain at the elastic bar measuring point and the radial displacement of the free end of the elastic support is accurately obtained through the calibration device, which provides a strong guarantee for the subsequent accurate acquisition of the real-time radial displacement value of the free end of the elastic support.

[0031] In this embodiment, the calibration device includes a mounting seat, a mounting plate for fixing the mounting edge of the elastic support on the mounting seat, a loading ring for sleeved on the outer wall of the elastic support, a loading rod connected to the loading ring for applying a radial load, a displacement sensor connected to the loading ring for measuring radial displacement, and a strain gauge for measuring strain at the strain measuring point. Specifically, the elastic support mounting plate is first rigidly fixed to the mounting seat by means of the mounting plate and bolts, and then the loading ring is rigidly connected to the outer wall of the free end of the elastic support, and the loading rod is installed below the loading ring to apply a radial load to the free end of the elastic support during the calibration process. The loading rod always maintains a plumb state, and the displacement sensor is installed above the loading ring to measure the radial displacement of the free end of the elastic support caused by the radial load during the calibration process, and at the same time, the strain at the elastic bar measuring point is measured by the strain gauge.

[0032] In this embodiment, in step S5, the strain test of the elastic support specifically includes the following steps: measuring the strain and temperature value of the elastic bar in real time during the operation of the engine by means of a strain gauge and a temperature sensor, obtaining the real-time radial displacement change of the free end of the elastic support according to the "strain-displacement" relationship and the real-time strain of the elastic bar, determining the real-time elastic modulus of the elastic bar material according to the real-time temperature value of the elastic bar, and then obtaining the real-time elastic bar stress value according to the real-time elastic modulus of the elastic bar material and the real-time strain of the elastic bar, and realizing real-time safety monitoring of the rotor during the engine test and obtaining accurate imbalance response value at the rotor journal according to the real-time radial displacement change of the free end of the elastic support and the real-time elastic bar stress value. Specifically, the real-time safety monitoring of the rotor is associated with the real-time radial displacement change of the free end of the elastic support and the real-time elastic bar stress value, and the unbalance response value at the rotor shaft neck is also associated with the real-time radial displacement change of the free end of the elastic support and the real-time elastic bar stress value. Therefore, by improving the test accuracy of the real-time radial displacement change of the free end of the elastic support and the real-time elastic bar stress value during the test, it is beneficial to ensure the real-time safety monitoring of the rotor during the engine test and obtain accurate unbalance response values ​​at the rotor shaft neck. It should be understood that when the elastic support is actually tested, the axial direction of the elastic support is arranged horizontally.

[0033] In this embodiment, step S3 specifically includes the following steps: according to the working boundary conditions of the spring support in the engine and the parameter information of the part material, select appropriate strain gauges, temperature sensors and corresponding pasting work, so as to paste the strain gauge at the strain measurement point position and paste the temperature sensor at the temperature measurement point position. Optionally, the temperature sensor is a thermocouple. Optionally, the part material parameter information mainly includes the type of part material. It should be understood that the specific pasting work in pasting the strain gauge and pasting the temperature sensor belongs to the well-known technology of those skilled in the art, and will not be repeated here.

[0034] In this embodiment, the working boundary conditions include working temperature and oil resistance. Specifically, the working temperature and lubricating oil lubrication conditions in different areas of the engine are different, so it is necessary to select appropriate strain gauges and temperature sensors according to the working temperature and oil resistance in the engine.

[0035] The squirrel cage spring of the aircraft engine of this embodiment is tested by the above-mentioned squirrel cage spring strain test method. Specifically, the squirrel cage spring of the aircraft engine is tested by the above-mentioned test method, which provides a test basis for the operation status monitoring and vibration troubleshooting of the rotor during the test run, makes a positive contribution to the research and development work, and effectively eliminates the vibration faults during the engine test run, reduces the risk and accident rate of the engine test run, and improves the safety of the engine test run.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A squirrel cage spring support strain test method, characterized in that: The following steps are involved: S1, according to the structural characteristics and working characteristics of the elastic support, a finite element analysis is performed on it to determine the position of the strain measuring point on the elastic bar that meets the first preset condition; S2, determining the temperature measuring point position that meets the second preset condition on the elastic bar according to the strain measuring point position; S3, attaching a strain gauge to the strain measuring point and attaching a temperature sensor to the temperature measuring point; S4, designing a calibration device according to the working boundary conditions of the elastic support in the engine, and calibrating the strain-displacement relationship between the strain at the elastic strip strain measuring point and the radial displacement of the free end of the elastic support by the calibration device using a loading calibration method; S5, install the spring support in the engine to carry out real-time spring support strain testing during the engine bench test.

2. The squirrel cage spring support strain test method according to claim 1, characterized in that: Step S1 specifically includes the following steps: According to the structural characteristics and working characteristics of the elastic support, the deformation characteristics of the elastic support under the working state are analyzed. When the elastic bar is deformed due to the radial displacement of the rotor journal, the strain distribution characteristics at each point on the elastic bar are analyzed, so as to determine the strain measurement point position of the elastic bar in the area with the strain distribution characteristics that meet the first preset condition.

3. The squirrel cage spring support strain testing method according to claim 1, characterized in that: Step S2 specifically includes the following steps: According to the position of the strain measuring point on the elastic strip, the same position on the same circular section as the strain measuring point position is determined on other elastic strips as the temperature measuring point position.

4. The squirrel cage spring support strain test method according to any one of claims 1 to 3, characterized in that: Step S4 specifically includes the following steps: A calibration device is designed according to the working boundary conditions of the spring bar in the engine. The calibration device rigidly fixes the installation edge of the spring bar by simulating the actual state, so that the installation edge after fixation is fully constrained. Then, within the elastic deformation range of the spring bar, radial loads are applied to the free end of the spring bar in the vertical and horizontal directions. At the same time, the strain values ​​at each strain measuring point on the spring bar and the radial displacement value of the free end of the spring bar are measured to obtain the corresponding relationship between the strain at the measuring point of the spring bar and the radial displacement of the free end of the spring bar.

5. The squirrel cage spring support strain testing method according to claim 4, characterized in that: The calibration device includes a mounting seat, a mounting plate for fixing the mounting edge of the elastic support on the mounting seat, a loading ring for sleeved on the outer wall of the elastic support, a loading rod connected to the loading ring for applying a radial load, a displacement sensor connected to the loading ring for measuring radial displacement, and a strain gauge for measuring strain at a strain measuring point.

6. The squirrel cage spring support strain testing method according to claim 4, characterized in that: In step S5, the strain test of the elastic support specifically includes the following steps: The strain and temperature of the spring clip during engine operation are measured in real time by means of strain gauges and temperature sensors. The real-time radial displacement change of the free end of the spring clip is obtained according to the strain-displacement relationship and the real-time strain of the spring clip. The real-time elastic modulus of the spring clip material is determined according to the real-time temperature of the spring clip. The real-time elastic modulus of the spring clip material and the real-time strain of the spring clip are used to obtain the real-time stress value of the spring clip. The real-time safety monitoring of the rotor during engine test and the accurate imbalance response value of the rotor journal are achieved according to the real-time radial displacement change of the free end of the spring clip and the real-time stress value of the spring clip.

7. The squirrel cage spring support strain testing method according to any one of claims 1 to 3, characterized in that: Step S3 specifically includes the following steps: According to the working boundary conditions of the spring support in the engine and the parameter information of the parts material, the strain gauge, the temperature sensor and the corresponding pasting work are selected to paste the strain gauge at the strain measuring point position and the temperature sensor at the temperature measuring point position.

8. The squirrel cage spring support strain testing method according to claim 7, characterized in that: Working boundary conditions include working temperature and oil resistance.

9. An aircraft engine squirrel cage spring, characterized in that: The test is conducted by the squirrel cage spring support strain test method as described in any one of claims 1 to 8.

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