Low-cycle fatigue test method for aero-engine wheel disc

Abstract

The invention discloses a low-cycle fatigue test method for an aero-engine wheel disc, and belongs to the technical field of aero-engines. According to the method, an elliptical hole is formed in a wheel disc eccentric hole part of a wheel disc test, and the short diameter of the elliptical hole penetrates through the position, where the maximum stress is located, of the eccentric hole part; therefore, the geometric mutation of the position of the maximum stress of the eccentric hole part is reduced, the stress concentration and the maximum equivalent stress of the eccentric hole part are reduced, and the fatigue life of the eccentric hole part of the test wheel disc is prolonged. The elliptical hole can eliminate the fatigue damage of the eccentric hole part of the test wheel disc in the low-cycle fatigue test process of the eccentric hole part, avoids the accumulation of the fatigue damage of the eccentric hole part, further prolongs the fatigue life of the eccentric hole part of the test wheel disc, enables the low-cycle fatigue test of the wheel center part of the test wheel disc to be smoothly carried out, and improves the test efficiency. And low-cycle fatigue test examination of the wheel center part and the eccentric hole part is realized on a single test wheel disc, so that the test cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engines, in particular to a low-cycle fatigue test method for an aero-engine wheel disc. Background Art

[0002] For the impeller of an aircraft engine, a low-cycle fatigue test needs to be carried out to verify whether the low-cycle fatigue life of the impeller meets the design requirements. During operation, the impeller is mainly subjected to the thermal stress of the gas environment and the centrifugal force of rotation. By calculating the stress at the dangerous point of the impeller and evaluating its low-cycle fatigue life, the assessment position is determined and uniform heating is performed according to the temperature of the working state of the assessment point. Since the test environment is uniform temperature, the thermal stress of the assessment position needs to be equivalent by increasing the test speed; The existing low-cycle fatigue test of the wheel can only perform uniform temperature heating and cannot take into account the thermal stress of the wheel during operation. The low-cycle fatigue test assessment parts of the wheel with an eccentric hole need to be assessed separately at multiple positions such as the eccentric hole and the wheel center. Since the stress of the eccentric hole is relatively high in the working state, when assessing the wheel center in the low-cycle fatigue test, after increasing the equivalent wheel center stress by increasing the speed, the stress of the eccentric hole is too high compared with the previous test stress, and the eccentric hole is prone to premature failure, and ultimately the purpose of assessing the low-cycle fatigue life of the wheel center cannot be achieved. The current common solution is to use two test wheels to assess the wheel center and the eccentric hole respectively, which consumes a lot of test materials and has high test costs.

[0003] Based on this, the present invention designs a low cycle fatigue test method for an aircraft engine wheel disc to solve the above problems. Summary of the invention

[0004] The invention provides a low cycle fatigue test method for an aircraft engine wheel disc, so as to solve the technical problem that the eccentric hole part of the wheel disc cannot pass the low cycle fatigue test assessment of the wheel center part.

[0005] According to one aspect of the present invention, a low cycle fatigue test method for an aircraft engine disk is provided, comprising the following steps: S100, finite element stress analysis of the working state of the wheel; Establish a finite element model of the wheel disc and perform finite element stress analysis under the working state of the wheel disc to obtain the temperature T1 and stress S1 of the eccentric hole part, and the temperature T2 and stress S2 of the wheel center part under the working state of the wheel disc; S200, the test load of the eccentric hole is determined; Apply a uniform temperature load of temperature T1 to the wheel finite element model and perform finite element stress analysis under the test state to determine the test speed N1 when the stress at the eccentric hole reaches S1; S300, low cycle fatigue test at eccentric hole; A low cycle fatigue test is carried out using a test wheel at a test speed N1 and a test temperature T1 to assess the eccentric hole of the wheel; S400, wheel center test load determination; Apply a uniform temperature load of temperature T2 to the wheel disc finite element model and perform finite element stress analysis under the test state to determine the test speed N2 when the stress at the wheel center reaches S2, the stress S3 at the eccentric hole, and the stress distribution at the eccentric hole, and use the stress S3 and temperature T2 to predict the fatigue life of the eccentric hole. When the eccentric hole cannot pass the low cycle fatigue test at the wheel center, perform step S500. When the eccentric hole can pass the low cycle fatigue test at the wheel center, perform step S600. S500, reprocessing eccentric holes; When no elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model, an elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model along the axial direction of the wheel disk, and the short radius direction of the elliptical hole is determined according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2. After the hole is formed, step S400 is performed; When an elliptical hole is formed at the eccentric hole portion on the wheel disc finite element model, the long radius and short radius of the ellipse are adjusted according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2, and step S400 is performed after the adjustment is completed; S600, low cycle fatigue test on wheel center; When no elliptical hole is provided on the wheel finite element model, a low cycle fatigue test is carried out with a test wheel at a rotation speed of N2 and a temperature of T2 to assess the wheel center of the test wheel; When an elliptical hole is opened on the finite element model of the wheel disc, an elliptical hole of the same size is opened at the same position on the test wheel disc, and a low cycle fatigue test is carried out at a rotation speed N2 and a temperature T2 to evaluate the wheel center of the test wheel disc.

[0006] As a further solution of the present invention, in S100, when performing finite element stress analysis of the wheel disc in working state, the working state adopts the maximum take-off state in standard weather.

[0007] As a further solution of the present invention, in S400, a fatigue damage accumulation method is used to predict the fatigue life of the eccentric hole portion.

[0008] As a further solution of the present invention, in S300 and S600, the test wheel disc is assembled to a test device for a low cycle fatigue test; the test device includes an adapter shaft, bolts and nuts, the adapter shaft includes a mounting edge for connecting to the test wheel disc, the mounting edge is used to abut against a stop at one end of the test wheel disc in the axial direction, and the mounting edge is fixedly connected to the test wheel disc by bolts and nuts.

[0009] As a further solution of the present invention, in S500, when an elliptical hole is opened on the finite element model of the wheel disk, the difference between the short radius of the elliptical hole and the radius of the eccentric hole is not less than 1 mm.

[0010] As a further solution of the present invention, in S500, when the elliptical hole is opened, the elliptical hole and the eccentric hole portion are coaxially arranged.

[0011] As a further solution of the present invention, in S500, when the long radius and short radius of the elliptical hole are adjusted according to the stress distribution of the eccentric hole when the stress at the wheel center reaches S2, when the distance from the position of the maximum stress at the eccentric hole to the short radius is smaller than the distance to the long radius, the long radius of the elliptical hole is increased; when the distance from the position of the maximum stress at the eccentric hole to the short radius is larger than the distance to the long radius, the short radius of the elliptical hole is increased.

[0012] As a further solution of the present invention, a surface of the mounting edge (11) in the axial direction of the test wheel disc for contacting the wheel disc is a first contact surface, and after the elliptical hole is provided in the test wheel disc, the contact area between the first contact surface and the test wheel disc is not less than half of the contact area before the elliptical hole is provided in the test wheel disc.

[0013] As a further solution of the present invention, the mass change of the wheel disc finite element model after the elliptical hole is opened is less than 5%.

[0014] As a further solution of the present invention, the average stress deformation of the wheel disc finite element model after the elliptical hole is opened is less than 5% of the average stress of the original wheel disc finite element model.

[0015] The present invention has the following beneficial effects: When the eccentric hole portion cannot pass the low-cycle fatigue test assessment of the wheel center portion, the method opens an elliptical hole at the eccentric hole portion of the wheel test disc, and the short diameter of the elliptical hole passes through the position where the maximum stress is located at the eccentric hole portion, thereby reducing the geometric mutation of the position where the maximum stress is located at the eccentric hole portion, reducing the stress concentration and the maximum equivalent stress at the eccentric hole portion, and increasing the fatigue life of the eccentric hole portion of the test wheel disc. At the same time, the opening of the elliptical hole can also eliminate the fatigue damage generated at the eccentric hole portion of the test wheel disc during the low-cycle fatigue test of the eccentric hole portion, avoid the accumulation of fatigue damage at the eccentric hole portion, and further increase the fatigue life of the eccentric hole portion of the test wheel disc, so that the low-cycle fatigue test of the wheel center portion of the test wheel disc can be carried out smoothly, and the low-cycle fatigue test assessment of the wheel center portion and the eccentric hole portion can be realized on a single test wheel disc, thereby reducing the test cost.

[0016] 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

[0017] 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: Figure 1 This is a schematic diagram of the roulette structure of the present invention; Figure 2 This is a schematic diagram of stress distribution before the elliptical hole is opened at the eccentric hole of the wheel; Figure 3 This is a schematic diagram of an elliptical hole opened at the eccentric hole of the wheel; Figure 4 This is a schematic diagram of stress distribution after an elliptical hole is opened in the eccentric hole of the wheel; Figure 5 It is a structural schematic diagram of the test device in the present invention; Figure 6 It is a flow chart of the present invention.

[0018] Legend: 1. Adapter shaft; 11. Mounting edge; 2. Bolt; 3. Nut. DETAILED DESCRIPTION

[0019] 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.

[0020] See also Figure 1-6 The present invention provides a technical solution: a low cycle fatigue test method for an aircraft engine wheel disc, comprising the following steps: S100, finite element stress analysis of the working state of the wheel; Establish a finite element model of the wheel disc and perform finite element stress analysis under the working state of the wheel disc to obtain the temperature T1 and stress S1 of the eccentric hole part, and the temperature T2 and stress S2 of the wheel center part under the working state of the wheel disc; Before the test, it is necessary to determine the stress and temperature of the wheel center and eccentric hole of the wheel disc under working conditions, so as to use them as test parameters for low cycle fatigue test. At the same time, the stress and temperature under working conditions are used to conduct low cycle fatigue test on the wheel center and eccentric hole to ensure the accuracy of the low cycle fatigue test results. S200, the test load of the eccentric hole is determined; Apply a uniform temperature load of temperature T1 to the wheel finite element model and perform finite element stress analysis under the test state to determine the test speed N1 when the stress at the eccentric hole reaches S1; Since the test environment is uniform temperature and has no thermal stress, when the low cycle fatigue test is performed at the same speed as the working state, the stress at the eccentric hole of the test wheel in the test environment will be different from the stress under the working state. Therefore, it is necessary to determine the test speed through temperature T1 and stress S1. First, a uniform temperature load of temperature T1 is applied to the wheel finite element model, and then a finite element stress analysis is performed under the test state. The speed of the wheel finite element model is adjusted until the stress at the eccentric hole of the wheel finite element model reaches S1. At this time, the speed of the wheel finite element model is the test speed N1 of the eccentric hole low cycle fatigue test.

[0021] S300, low cycle fatigue test at eccentric hole; A low cycle fatigue test is carried out using a test wheel at a test speed N1 and a test temperature T1 to assess the eccentric hole position; After obtaining the test temperature T1 and the test speed N1, the low cycle fatigue test can be started. During the test, the temperature of the test wheel is controlled at T1, and the speed of the test wheel reaches N1. At this time, the stress of the eccentric hole of the test wheel reaches S1, ensuring the accuracy of the assessment results; S400, wheel center test load determination; Apply a uniform temperature load of temperature T2 to the wheel disc finite element model and perform finite element stress analysis under the test state to determine the test speed N2 when the stress at the wheel center reaches S2, the stress S3 at the eccentric hole, and the stress distribution at the eccentric hole, and use the stress S3 and temperature T2 to predict the fatigue life of the eccentric hole. When the eccentric hole cannot pass the low cycle fatigue test at the wheel center, perform step S500. When the eccentric hole can pass the low cycle fatigue test at the wheel center, perform step S600. Before conducting a low cycle fatigue test on the wheel center, the test speed needs to be determined. First, a uniform temperature load of temperature T2 is applied to the wheel disc finite element model, and then a finite element stress analysis is performed under the test state. The test speed of the wheel disc finite element model is adjusted until the stress of the wheel center of the wheel disc finite element model reaches S2. At this time, the speed of the wheel disc finite element model is the test speed N2 of the eccentric hole low cycle fatigue test. At the same time, it is necessary to determine the stress S3 and stress distribution of the eccentric hole when the stress S2 is reached at the wheel center, and use the stress S3 and temperature T2 to predict the fatigue life of the eccentric hole to determine whether the eccentric hole can pass the subsequent low-cycle fatigue test of the wheel center. If not, proceed to S500; if yes, proceed to S600. S500, reprocessing eccentric holes; When no elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model, an elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model along the axial direction, and the short radius direction of the elliptical hole is determined according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2. After the hole is formed, step S400 is performed; According to the stress distribution of the eccentric hole when the stress at the wheel center reaches S2, an elliptical hole is opened at the eccentric hole position, so that the geometric mutation of the large stress area at the eccentric hole position is reduced, the maximum equivalent stress at the eccentric hole position is reduced, and the fatigue life of the eccentric hole position is increased, so that the low cycle fatigue test at the wheel center position can be successfully completed. like Figure 2 As shown in Figure 2, the maximum stress at the eccentric hole is located on the side of the eccentric hole close to the axis of the wheel finite element model. Therefore, Figure 3 As shown in the figure, when the elliptical hole is opened, the short radius direction of the elliptical hole coincides with the radial direction of the wheel disk finite element model, so that the geometric mutation of the eccentric hole part close to the axis of the wheel disk finite element model is reduced, the stress concentration is reduced, the maximum equivalent stress of the eccentric hole part is reduced, and the fatigue life of the eccentric hole part is increased; At the same time, the elliptical hole can also remove the fatigue damage generated in the eccentric hole during the low-cycle fatigue test of the eccentric hole, avoid the accumulation of fatigue damage in the eccentric hole, and further increase the fatigue life of the eccentric hole. After the elliptical hole is opened, the mass of the wheel finite element model will change, so it is necessary to re-determine the test speed N2. At the same time, it is necessary to determine the stress level and stress distribution of the eccentric hole after the elliptical hole is opened, and determine whether the eccentric hole after the elliptical hole is opened can pass the low-cycle fatigue test of the wheel center. Therefore, it is necessary to return to S400; When an elliptical hole is formed at the eccentric hole portion on the wheel disc finite element model, the long radius and short radius of the ellipse are adjusted according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2, and step S400 is performed after the adjustment is completed; When the elliptical hole is opened in the wheel disc finite element model, the eccentric hole part still cannot pass the low cycle fatigue test of the wheel center part, then the size of the elliptical hole needs to be adjusted, and the stress level and stress distribution of the eccentric hole part after the elliptical hole is opened need to be referred to during the adjustment; S600, low cycle fatigue test on wheel center; When no elliptical hole is provided on the wheel finite element model, a low cycle fatigue test is carried out with a test wheel at a speed of N2 and a temperature of T2 to assess the wheel center. When an elliptical hole is opened on the wheel disc finite element model, an elliptical hole of the same size is opened at the same position on the test wheel disc, and a low cycle fatigue test is carried out at a speed of N2 and a temperature of T2 to assess the wheel center. After the eccentric hole part is predicted by S400 to pass the low cycle fatigue test of the wheel center part, the low cycle fatigue test of the wheel center part can be started. When an elliptical hole is opened on the finite element model of the wheel disc, an elliptical hole is opened on the test wheel disc according to the position and size of the elliptical hole on the finite element model of the wheel disc, and then the low cycle fatigue test of the wheel center part is started. When there is no elliptical hole on the finite element model of the wheel disc, there is no need to open an elliptical hole on the test wheel disc, and the low cycle fatigue test of the wheel center part is directly carried out. During the test, the temperature of the test wheel disc is controlled at T2, and the speed of the test wheel disc reaches N2. At this time, the stress of the wheel center part of the test wheel disc reaches S2, ensuring the accuracy of the assessment results; When the eccentric hole portion cannot pass the low-cycle fatigue test assessment of the wheel center portion, the method opens an elliptical hole at the eccentric hole portion of the wheel test disc, and the short diameter of the elliptical hole passes through the position where the maximum stress is located at the eccentric hole portion, thereby reducing the geometric mutation of the position where the maximum stress is located at the eccentric hole portion, reducing the stress concentration and the maximum equivalent stress at the eccentric hole portion, and increasing the fatigue life of the eccentric hole portion of the test wheel disc. At the same time, the opening of the elliptical hole can also eliminate the fatigue damage generated at the eccentric hole portion of the test wheel disc during the low-cycle fatigue test of the eccentric hole portion, avoid the accumulation of fatigue damage at the eccentric hole portion, and further increase the fatigue life of the eccentric hole portion of the test wheel disc, so that the low-cycle fatigue test of the wheel center portion of the test wheel disc can be carried out smoothly, and the low-cycle fatigue test assessment of the wheel center portion and the eccentric hole portion can be realized on a single test wheel disc, thereby reducing the test cost.

[0022] Specifically, in S100, when performing finite element stress analysis under the working state of the wheel, the working state adopts the maximum take-off state in standard weather; Simulating the most severe working conditions, the mechanical and thermal loads on the aircraft engine reach their peak values ​​under the maximum takeoff state. The core of the low cycle fatigue test is the damage accumulation caused by high stress amplitude. The stress level under the maximum takeoff state is the highest, which is the main working condition that causes the wheel failure. Testing under this state can ensure that the wheel design can still meet the safety margin requirements under the worst conditions. At the same time, the engine may reduce thrust due to surge margin limitations in non-standard weather conditions (such as high temperature and plateau). At this time, the mechanical load is actually less than the maximum takeoff thrust in standard weather. Therefore, the maximum takeoff state in standard weather is actually the theoretical maximum load that the wheel can withstand, covering all actual operating conditions.

[0023] Specifically, in S400, when predicting the fatigue life of the eccentric hole part, the fatigue damage accumulation method is used to predict the fatigue life of the eccentric hole part, which is closer to the complex working conditions in the actual working process and the prediction result is more accurate. The use of fatigue damage accumulation to predict fatigue life is a conventional technical means in this field.

[0024] Specifically, in S300 and S600, the test wheel disc is assembled into the test device to perform a low cycle fatigue test; like Figure 5 As shown, the test device includes an adapter shaft 1, a bolt 2 and a nut 3. The adapter shaft 1 includes a mounting edge 11 for connecting with the test wheel disc. The mounting edge 11 is used to abut against a stopper at one end of the test wheel disc in the axial direction. The mounting edge 11 is fixedly connected to the test wheel disc through the bolt 2 and the nut 3. The mounting edge 11 is provided with 2 bolt holes for passing the bolts 2, and the number and position of the 2 bolt holes on the mounting edge 11 correspond to the number and position of the eccentric holes on the test wheel disc. When the test wheel disc is mounted on the adapter shaft 1, the mounting edge 11 is abutted against one of the stoppers of the test wheel disc, and the 2 bolt holes are aligned with the eccentric holes on the test wheel disc. After alignment, the bolts 2 are passed through and the nuts 3 are assembled to realize the connection between the test wheel disc and the adapter shaft 1. The end of the adapter shaft 1 away from the mounting edge 11 is used to be connected to the torque output mechanism, and the adapter shaft 1 is driven by the torque output mechanism to drive the test wheel disc to rotate; The size of the nut 3 can be changed according to the size of the elliptical hole to ensure that the nut 3 has a sufficient contact area with the test wheel.

[0025] Specifically, in S500, when an elliptical hole is opened on the wheel disc finite element model, the difference between the short radius of the elliptical hole and the radius of the eccentric hole is not less than 1 mm; When the eccentric hole of the test wheel is subjected to a low cycle fatigue test in S300, fatigue damage will occur in the eccentric hole. The difference between the short radius of the elliptical hole and the radius of the eccentric hole is not less than 1mm, ensuring that the elliptical hole can eliminate the fatigue damage of the eccentric hole and preventing the short diameter of the elliptical hole from being too small to completely eliminate the fatigue damage.

[0026] Specifically, in S500, when the elliptical hole is opened, the elliptical hole is coaxially arranged with the eccentric hole portion to prevent the elliptical hole from affecting the dynamic balance of the test wheel.

[0027] Specifically, in S500, when the long radius and short radius of the elliptical hole are adjusted according to the stress distribution of the eccentric hole when the stress at the wheel center reaches S2, when the distance from the position where the maximum stress at the eccentric hole is located to the short radius is smaller than the distance to the long radius, the long radius of the elliptical hole is increased; when the distance from the position where the maximum stress at the eccentric hole is located to the short radius is larger than the distance to the long radius, the short radius of the elliptical hole is increased; After an elliptical hole is opened at the eccentric hole part of the wheel disk finite element model, it is necessary to return to S400 for finite element stress analysis to determine whether the eccentric hole part after the elliptical hole is opened can pass the low cycle fatigue test of the wheel center part. If it still cannot pass the low cycle fatigue test of the wheel center part, the size of the elliptical hole needs to be adjusted. When adjusting the size of the elliptical hole, it is necessary to adjust it according to the stress distribution of the eccentric hole part. When the current maximum stress at the eccentric hole part is closer to the short radius of the elliptical hole, the long radius of the elliptical hole is increased, the geometric mutation on the short radius side of the elliptical hole is reduced, and the stress concentration is reduced. When the current maximum stress at the eccentric hole part is closer to the long radius of the elliptical hole, the short radius of the elliptical hole is increased, the geometric mutation on the long radius side of the elliptical hole is reduced, and the stress concentration is reduced. Corresponding adjustments are made according to actual conditions. The specific adjustment range of the short radius and the long radius is determined according to the actual stress size, so as to achieve accurate and rapid adjustment of the elliptical hole size and reduce the elliptical hole size adjustment time.

[0028] like Figure 4 As shown in the figure, after the elliptical hole is opened in the eccentric hole part, it still cannot pass the low cycle fatigue test of the wheel center part, and at this time the maximum stress in the eccentric hole part is located on the long radius side of the elliptical hole. At this time, the short radius of the elliptical hole can be increased to reduce the geometric mutation on the long radius side of the elliptical hole, reduce the stress concentration on the long radius side of the elliptical hole, and thus increase the fatigue life of the eccentric hole part.

[0029] The side of the mounting edge 11 in the axial direction of the test wheel disc that is used to contact the test wheel disc is the first contact surface. After the elliptical hole is opened in the test wheel disc, the contact area between the test wheel disc and the first contact surface will be reduced, and the friction between the first contact surface and the test wheel disc will be reduced. At this time, the stress concentration coefficient at the edge of the eccentric hole increases to compensate for the reduction in friction caused by the reduction in contact area. Therefore, the contact area between the first contact surface and the test wheel disc after the elliptical hole is opened in the test wheel disc is not less than half of the contact area before the elliptical hole is opened in the test wheel disc, thereby controlling the stress concentration coefficient at the edge of the eccentric hole and increasing the fatigue life of the eccentric hole.

[0030] Specifically, the mass change of the wheel disc finite element model after the elliptical hole is opened is less than 5%, and the mass reduction is controlled within 5%, which avoids excessive weakening of the structural strength and makes the fatigue life of the eccentric hole part more significantly improved. At the same time, the influence of the mass change on the test rotational inertia of the wheel disc is reduced, and the influence of the elliptical hole on the overall stiffness of the test wheel disc is reduced. The original characteristics are basically maintained, and the test results are closer to the actual working conditions.

[0031] Specifically, the average stress deformation of the wheel disk finite element model after the elliptical hole is opened is 5% less than the average stress of the original wheel disk finite element model, which can limit the local maximum strain within the material fatigue limit and reduce the impact on fatigue life.

[0032] The above are only preferred embodiments of the present invention and are 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 low cycle fatigue test method for an aircraft engine disk, characterized in that: The following steps are involved: S100: Finite element stress analysis of the working state of the wheel; Establish a finite element model of the wheel disc and perform finite element stress analysis under the working state of the wheel disc to obtain the temperature T1 and stress S1 of the eccentric hole part, and the temperature T2 and stress S2 of the wheel center part under the working state of the wheel disc; S200: Determination of test load at eccentric hole location; Apply a uniform temperature load of temperature T1 to the wheel finite element model and perform finite element stress analysis under the test state to determine the test speed N1 when the stress at the eccentric hole reaches S1; S300: Low cycle fatigue test on eccentric hole; A low cycle fatigue test is carried out using a test wheel at a test speed N1 and a test temperature T1 to assess the eccentric hole position; S400: Determination of the test load at the wheel center; Apply a uniform temperature load of temperature T2 to the wheel disc finite element model and perform finite element stress analysis under the test state to determine the test speed N2 when the stress at the wheel center reaches S2, the stress S3 at the eccentric hole, and the stress distribution at the eccentric hole, and use the stress S3 and temperature T2 to predict the fatigue life of the eccentric hole. When the eccentric hole cannot pass the low cycle fatigue test at the wheel center, perform step S500. When the eccentric hole can pass the low cycle fatigue test at the wheel center, perform step S600. S500: Reprocessing eccentric holes; When no elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model, an elliptical hole is formed at the eccentric hole portion on the wheel disk finite element model along the axial direction, and the short radius direction of the elliptical hole is determined according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2. After the hole is formed, step S400 is performed; When an elliptical hole is formed at the eccentric hole portion on the wheel disc finite element model, the long radius and short radius of the ellipse are adjusted according to the stress distribution at the eccentric hole portion when the stress at the wheel center portion reaches S2, and step S400 is performed after the adjustment is completed; S600: Low cycle fatigue test on wheel center; When no elliptical hole is provided on the wheel finite element model, a low cycle fatigue test is carried out with a test wheel at a speed of N2 and a temperature of T2 to assess the wheel center. When an elliptical hole is opened on the finite element model of the wheel disc, an elliptical hole of the same size is opened at the same position on the test wheel disc, and a low cycle fatigue test is carried out at a rotation speed N2 and a temperature T2 to evaluate the wheel center.

2. A low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S100, when performing finite element stress analysis of the wheel disc in working state, the working state adopts the maximum take-off state in standard weather.

3. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S400, the fatigue damage accumulation method is used to predict the fatigue life of the eccentric hole.

4. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S300 and S600, the test disc is assembled into the test rig for low cycle fatigue testing; The test device comprises an adapter shaft (1), a bolt (2) and a nut (3); the adapter shaft (1) comprises a mounting edge (11) for connecting to a test wheel disc; the mounting edge (11) is used to abut against a stop at one end of the test wheel disc in the axial direction; the mounting edge (11) and the test wheel disc are fixedly connected via the bolt (2) and the nut (3).

5. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S500, when an elliptical hole is opened on the wheel disc finite element model, the difference between the short radius of the elliptical hole and the radius of the eccentric hole is not less than 1 mm.

6. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S500, when the elliptical hole is formed, the elliptical hole and the eccentric hole are coaxially arranged.

7. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: In S500, when the long radius and short radius of the elliptical hole are adjusted according to the stress distribution at the eccentric hole when the stress at the wheel center reaches S2, when the distance from the position where the maximum stress is located at the eccentric hole to the short radius is smaller than the distance to the long radius, the long radius of the elliptical hole is increased; when the distance from the position where the maximum stress is located at the eccentric hole to the short radius is larger than the distance to the long radius, the short radius of the elliptical hole is increased.

8. The low cycle fatigue test method for an aircraft engine disk according to claim 4, characterized in that: A surface of the mounting edge (11) in the axial direction of the test wheel disc for contacting the wheel disc is a first contact surface. After the test wheel disc is provided with the elliptical hole, the contact area between the first contact surface and the test wheel disc is not less than half of the contact area before the test wheel disc is provided with the elliptical hole.

9. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: The mass change of the wheel disk finite element model after the elliptical hole is opened is less than 5%.

10. The low cycle fatigue test method for an aircraft engine disk according to claim 1, characterized in that: The average stress deformation of the wheel disk finite element model after the elliptical hole is opened is 5% less than the average stress of the original wheel disk finite element model.

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