Design method for simulators for predicting low cycle fatigue performance of engine disks

Abstract

The application discloses a design method of a simulation piece for predicting low-cycle fatigue performance of an engine wheel disc, comprising the following steps: extracting structural features of a workpiece to be simulated, and performing stress analysis on the structural features by using finite elements; performing equivalent simplification processing on the extracted structural features; performing stress analysis on the simulation piece by using finite elements, and adjusting the simulation piece until the stress gradient and the strain gradient of the simulation piece are consistent with the structural features if the stress gradient and the strain gradient of the simulation piece are inconsistent with the structural features; performing low-cycle fatigue test on the simulation piece, and performing rotating fatigue test on the workpiece to be simulated, and adjusting the simulation piece until the fatigue failure position and the fatigue failure mode of the simulation piece are consistent with the workpiece to be simulated if the fatigue failure position and the fatigue failure mode of the simulation piece are inconsistent with the workpiece to be simulated. The application only needs to reasonably correct equivalent loading positions and equivalent loads, does not need to redesign the structural features, and the test result can predict the service life of the wheel disc and evaluate the safety of the wheel disc.

Description

Technical Field

[0001] This invention belongs to the field of metal material performance testing technology, specifically relating to a design method for a simulation component used to predict the low-cycle fatigue performance of an engine disk. Background Technology

[0002] As is well known, the turbine disk is a crucial structural component in aero-engines. During structural design, disk safety must be prioritized, especially the fatigue failure of aero-engine turbine disks. Taking compressor disks as an example, the disk structure often exhibits areas of abrupt changes in cross-section or geometric discontinuities, such as the central hole or eccentric vent. These areas experience significant stress concentration under static or cyclic loads, causing local stress and strain in these regions to exceed the elastic deformation range and enter plastic deformation. Numerous engineering studies have confirmed that these stress concentration points are often the weakest points of the entire disk. Furthermore, stress concentration in these geometrically discontinuous areas leads to a non-uniform stress field distribution within the component structure, resulting in a significant stress gradient. This stress gradient is also a crucial factor to consider when assessing component fatigue failure.

[0003] Given the current dispersed nature of materials, the complexity of processes, loads, and environments, and the limitations of low-cycle fatigue life prediction methods, which result in significant errors in life prediction, conducting low-cycle fatigue tests on actual wheel disks or substructures and model disks that closely resemble actual wheel disks under simulated operating conditions is crucial for designing wheel disks with sufficiently low-cycle fatigue life. However, conducting component-level performance tests on wheel disks is extremely costly. Therefore, by combining the finite element analysis results of the wheel disk with the calculation results of the wheel disk's critical points, a simulated component is designed to simulate the stress conditions of the wheel disk's critical characteristic structures. Performance fatigue tests are then conducted on the simulated component in a laboratory environment. The test results can be used to predict the wheel disk's life and directly assess whether the wheel disk is safe under specific operating conditions.

[0004] The invention patent application CN114861317A discloses a design method for a low-cycle fatigue simulation component of the chamfered portion of the lower edge plate of a single-crystal turbine blade. The method includes the following steps: extracting shape and size characteristic parameters for the chamfered portion of the blade's lower edge plate; preliminarily designing the shape of the simulation component while ensuring that the geometry of the critical area is identical; ensuring that the maximum Schmid stress amplitude along the critical path direction at the typical location of the critical area of ​​the simulation component and the chamfered portion of the real blade's lower edge plate remains consistent within a critical distance range; determining the eccentricity distance between the test section and the clamping section of the simulation component based on finite element simulation; the simulation component's processing technology is the same as that of the real turbine blade, and its microstructure should be as consistent as possible with the test area. Considering the influence of the uncertainty of the blade's second crystal orientation, the simulation component should cover at least six different second crystal orientations; the outer surface of the turbine blade is usually coated, and the outer surface of the simulation component needs to be coated with the same grade of coating using the same process. The structure of the simulated hazardous parts designed in this technical solution is different from the structure of the actual hazardous parts of the blade. Therefore, the test results made using the simulated parts cannot directly represent the test results of the actual workpiece, and there will be a large error and low reliability. Moreover, this technical solution has done a lot of theoretical calculations, but the theoretical calculations have made many approximations to the actual situation, and there are often differences compared with the actual situation. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a design method for a simulation component used to predict the low-cycle fatigue performance of an engine disk, comprising the following steps in sequence:

[0006] Step 1: Based on the actual condition of the workpiece to be simulated, extract the structural features and their corresponding dimensions on the workpiece.

[0007] Step 2: Based on the extracted structural features and their corresponding dimensions, the stress state of the structural features is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software, respectively, to obtain the stress gradient distribution and strain gradient distribution of the structural features under the simulation of the two mechanical methods.

[0008] Step 3: Perform equivalent simplification on the structural features that are adjacent to or near the extracted structural features and have no obvious structural strength relationship with them, as well as their corresponding structural feature dimensions. The structural features after equivalent simplification have the same shape and size as the workpiece to be simulated.

[0009] Step 4: Design the simulation model. The structural features after equivalent simplification are used as the gauge length of the simulation part. The cylinder with threads on the outer surface is used as the two clamping sections of the simulation part. The two clamping sections are smoothly connected to the two ends of the gauge length section through transition sections. The central axis of the two clamping sections coincides with the geometric central axis of the gauge length section.

[0010] Step 5: Based on the simulated part model, use the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software to analyze the stress state of the simulated part, and obtain the stress gradient distribution and strain gradient distribution of the simulated part under the simulation of the two mechanical methods, and compare them with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods.

[0011] Step Six: Based on the comparison results of the stress gradient distribution and strain gradient distribution under the two mechanical methods, if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then the design of the simulated part model is completed; if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are inconsistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then it is necessary to adjust the parallel offset position and parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge length segment in the simulated part model.

[0012] Step 7: Based on the adjusted simulation model, the stress state of the simulation component is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software. The stress gradient distribution and strain gradient distribution of the simulation component under the simulation of the two mechanical methods are obtained respectively, and compared with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods.

[0013] Step 8: Repeat steps 6 and 7 until the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods. The design of the simulated part model is then complete.

[0014] Step 9: Fabricate a simulated part based on the simulated part model and conduct low-cycle fatigue tests on it to obtain the low-cycle fatigue performance test results of the simulated part; at the same time, conduct a rotational fatigue test on the workpiece to be simulated to obtain the low-cycle fatigue performance test results of the workpiece to be simulated.

[0015] Step 10: Compare the low-cycle fatigue performance test results of the simulated part with those of the workpiece to be simulated. If the fatigue failure location and mode of the simulated part are consistent with those of the workpiece to be simulated, the design of the simulated part is completed. If the fatigue failure location and mode of the simulated part are inconsistent with those of the workpiece to be simulated, the parallel offset position and the parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge segment in the simulated part model need to be readjusted.

[0016] Step 11: Repeat steps 7 to 10 until the fatigue failure location and mode of the simulated part are consistent with the fatigue failure location and mode of the workpiece to be simulated. This completes the design of the simulated part used to predict the low-cycle fatigue performance of the engine disk.

[0017] Preferably, in step one, the workpiece to be simulated is an aircraft engine disc-type part, and the structural features include any one or more of the following: small hole, chamfer, transition arc, tilt angle, sector and annulus, and the dimensions of the structural features include any one or more of the following: radius, diameter, arc length and angle.

[0018] In any of the above schemes, it is preferred that, in step four, the gauge section, clamping section and transition section of the simulation part are designed as an integrated unit, and the thread size of the outer surface of the clamping section needs to be determined according to the actual capacity of the low-cycle fatigue testing machine and the thread size of the corresponding clamping fixture.

[0019] In any of the above schemes, it is preferred that, in step four, while designing the simulation model, the equivalent loading position and equivalent load of the simulation component need to be determined; the equivalent loading position of the simulation component is adjusted in the horizontal plane, and the magnitude of the equivalent load is adjusted at the same time.

[0020] In any of the above schemes, it is preferred that, in steps six and ten, the parallel offset position and the parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge segment in the simulation model are adjusted so that the two central axes are parallel but not coaxial.

[0021] In any of the above schemes, it is preferred that, in step nine, a low-cycle fatigue testing machine is used to perform a low-cycle fatigue test on the simulated part, and a rotational fatigue testing machine is used to perform a rotational fatigue test on the simulated workpiece; the loading method of the low-cycle fatigue testing machine is a vertical tensile-compressive loading.

[0022] In any of the above embodiments, it is preferred that the finite element simulation software includes any one or more of Abaqus, Ansys, MSC.Marc, and Isight, and the finite element simulation software is used to calculate and analyze the structural features and the stress state of the simulated component, wherein the stress state includes any one or more of elastic stress, elastic strain, plastic stress, plastic strain, and stress-strain distribution.

[0023] In step three of this invention, it is necessary to perform equivalent simplification processing on small structural features and their corresponding dimensions that are adjacent to or near the extracted structural features and have no obvious structural strength relationship with them. Based on the fatigue failure location of actual aero-engine disc-type parts and the size of structural feature parts on the workpiece to be simulated, it is inevitable to use some nearby structural features and their dimensions when designing the simulation part. Since the design of aero-engine disc-type parts is relatively compact, some nearby structural features and their dimensions are only adjacent to the actual fatigue failure structural features and their dimensions, and have no obvious structural strength relationship. They have almost no impact on the subsequent test results of the simulation part. Therefore, when designing the simulation part, these unaffected structural features and their dimensions can be ignored or combined to reduce the processing steps and processing cost of the simulation part.

[0024] In step four of this invention, since the clamping section of the simulated part is a cylinder with threads on its outer surface, and the structural features of the workpiece to be simulated include special structures such as small holes and chamfers, and the loading method of the low-cycle fatigue testing machine is tensile and compressive loading in the vertical direction, the equivalent loading position of the simulated part should be adjusted and designed in the horizontal plane in the finite element simulation calculation, and the magnitude of the loading force should be adjusted so that the fatigue failure position and fatigue failure mode of the simulated part are consistent with those of the workpiece to be simulated.

[0025] This invention presents a design method for a simulated component used to predict the low-cycle fatigue performance of an engine disk. This method is simple, convenient, and easy to operate. Through structural simplification and finite element simulation, the method analyzes the elastic stress, elastic strain, plastic stress, plastic strain, and stress-strain distribution of the simulated component. It then adjusts the equivalent loading position and equivalent load of the simulated component to achieve the fatigue failure mode and location of the workpiece being simulated, thereby simulating the stress state of critical structural features of the disk. Finally, a performance-based fatigue test is conducted on the simulated component in a laboratory environment. Since this invention's design method only involves rationalizing the equivalent loading position and equivalent load without redesigning structural features and dimensions, the test results can be used to predict the disk's lifespan and directly assess the disk's safety under specific operating conditions. Attached Figure Description

[0026] Figure 1 A flowchart of a preferred embodiment of the design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to the present invention;

[0027] Figure 2 for Figure 1 A schematic diagram of the structural feature on the workpiece to be simulated in step one of the embodiments shown. The structural feature is an oblique hole at the center of the aero-engine wheel disk.

[0028] Figure 3 for Figure 1 In step two of the embodiment shown, the structural features are simulated by the linear elasticity method, including the stress gradient distribution and strain gradient distribution, where: (1) is the stress gradient distribution diagram, and (2) is the strain gradient distribution diagram;

[0029] Figure 4 for Figure 1 The stress gradient distribution and strain gradient distribution of the structural features in step two of the embodiment shown are simulated by the elastoplastic mechanics method, where: (1) is the stress gradient distribution diagram, and (2) is the strain gradient distribution diagram;

[0030] Figure 5 for Figure 1 The three-dimensional model of the simulated component in step four of the embodiment shown is a simplified structural feature of the simulated component.

[0031] Figure 6 for Figure 1 The stress gradient distribution and strain gradient distribution of the simulated part obtained in the embodiment shown are simulated by the online elasticity method, where: (1) is the stress gradient distribution diagram, and (2) is the strain gradient distribution diagram;

[0032] Figure 7 for Figure 1 The stress gradient distribution and strain gradient distribution of the final simulated part obtained in the embodiment shown are simulated by the elastoplastic mechanics method, where: (1) is the stress gradient distribution diagram and (2) is the strain gradient distribution diagram.

[0033] The diagram is labeled as follows: 1-gauge length section, 2-clamping section, 3-transition section. Detailed Implementation

[0034] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0035] like Figure 1 As shown, a preferred embodiment of the design method for a simulation component used to predict the low-cycle fatigue performance of an engine disk according to the present invention includes the following steps in sequence:

[0036] Step 1: Based on the actual condition of the workpiece to be simulated, extract the structural features and their corresponding dimensions on the workpiece.

[0037] Step 2: Based on the extracted structural features and their corresponding dimensions, the stress state of the structural features is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software, respectively, to obtain the stress gradient distribution and strain gradient distribution of the structural features under the simulation of the two mechanical methods.

[0038] Step 3: Perform equivalent simplification on the structural features that are adjacent to or near the extracted structural features and have no obvious structural strength relationship with them, as well as their corresponding structural feature dimensions. The structural features after equivalent simplification have the same shape and size as the workpiece to be simulated.

[0039] Step 4: Design the simulation model. The structural features after equivalent simplification are used as the gauge length of the simulation part. The cylinder with threads on the outer surface is used as the two clamping sections of the simulation part. The two clamping sections are smoothly connected to the two ends of the gauge length section through transition sections. The central axis of the two clamping sections coincides with the geometric central axis of the gauge length section.

[0040] Step 5: Based on the simulated part model, use the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software to analyze the stress state of the simulated part, and obtain the stress gradient distribution and strain gradient distribution of the simulated part under the simulation of the two mechanical methods, and compare them with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods.

[0041] Step Six: Based on the comparison results of the stress gradient distribution and strain gradient distribution under the two mechanical methods, if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then the design of the simulated part model is completed; if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are inconsistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then it is necessary to adjust the parallel offset position and parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge length segment in the simulated part model.

[0042] Step 7: Based on the adjusted simulation model, the stress state of the simulation component is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software. The stress gradient distribution and strain gradient distribution of the simulation component under the simulation of the two mechanical methods are obtained respectively, and compared with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods.

[0043] Step 8: Repeat steps 6 and 7 until the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods. The design of the simulated part model is then complete.

[0044] Step 9: Fabricate a simulated part based on the simulated part model and conduct low-cycle fatigue tests on it to obtain the low-cycle fatigue performance test results of the simulated part; at the same time, conduct a rotational fatigue test on the workpiece to be simulated to obtain the low-cycle fatigue performance test results of the workpiece to be simulated.

[0045] Step 10: Compare the low-cycle fatigue performance test results of the simulated part with those of the workpiece to be simulated. If the fatigue failure location and mode of the simulated part are consistent with those of the workpiece to be simulated, the design of the simulated part is completed. If the fatigue failure location and mode of the simulated part are inconsistent with those of the workpiece to be simulated, the parallel offset position and the parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge segment in the simulated part model need to be readjusted.

[0046] Step 11: Repeat steps 7 to 10 until the fatigue failure location and mode of the simulated part are consistent with the fatigue failure location and mode of the workpiece to be simulated. This completes the design of the simulated part used to predict the low-cycle fatigue performance of the engine disk.

[0047] In step one, the workpiece to be simulated is an aircraft engine disk, and the structural feature is an oblique hole at the center of the disk, the shape of which is as follows: Figure 2 As shown. The specific dimensions of the inclined hole are obtained based on the actual situation of the roulette wheel or the roulette wheel design drawings. The diameter of the inclined hole is 6.8mm, the angle between the central axis of the inclined hole and the axis of the roulette wheel is 65°, the opening of the inclined hole is rounded with a radius of 1mm, one side of the inclined hole is a thin wall with a thickness of 3.95mm, and there are two C0.5 chamfers at the transition from the thin wall side to the opening. The total length of the inclined hole is 31.6mm.

[0048] In step two, the stress and strain at the rounded edge of the hole under a given load is calculated using linear elastic mechanics, which is basically consistent with the theory. Since the maximum principal stress and the maximum equivalent stress both exceed the yield strength of the actual material of the workpiece being simulated, it is necessary to perform elastoplastic mechanics calculations. The analysis shows that the location of the maximum stress and strain changes from the hole opening to the thin-walled side of the hole near the hole opening.

[0049] In this embodiment, the stress state of the inclined hole is analyzed using the finite element simulation software Ansys. The stress gradient distribution and strain gradient distribution obtained under the linear elasticity method are as follows: Figure 3 As shown, the stress gradient distribution and strain gradient distribution obtained under the elastoplastic mechanics simulation method are as follows: Figure 4 As shown.

[0050] In step three, based on the fatigue failure location and hole size of the actual aero-engine disk center inclined hole, it is inevitable to use some nearby structural features and their dimensions when designing the simulation part. Since the design of the aero-engine disk center inclined hole is relatively compact, some nearby structural features and their dimensions are only adjacent to the actual fatigue failure structural features and their dimensions, and have no obvious structural strength relationship. They have almost no impact on the test results of the subsequent simulation part. Therefore, when designing the simulation part, these unaffected structural features and their dimensions can be ignored or combined to reduce the processing steps of the simulation part and reduce the processing cost of the simulation part.

[0051] In this embodiment, the theoretical failure location of the oblique hole is near the hole opening. The transition chamfer near the hole opening and the total length of the oblique hole have no substantial impact on the failure. Therefore, the two transition chamfers near the hole opening and the total length of the oblique hole can be ignored.

[0052] In step four, since the actual failure location of the workpiece to be simulated is also near the hole opening on the thin-walled side inside the hole, the various parts of the simulation part are designed using 3D modeling based on the testing capabilities of the low-cycle fatigue testing machine and the specifications of the existing tooling fixtures. While designing the simulation part, it is necessary to determine the equivalent loading position and equivalent load. The equivalent loading position of the simulation part is adjusted in the horizontal plane, and the magnitude of the equivalent load is also adjusted.

[0053] In this embodiment, the cross-section of the gauge length section is determined to be trapezoidal to correspond to the tilt angle of the workpiece to be simulated and the thin-walled side inside the hole. The total length of the hole is designed to be 10mm. The hole diameter, tilt angle, and dimensions of each chamfer and rounding are consistent with those of the workpiece to be simulated. Based on the 3D modeling results, the clamping section is determined to be a threaded clamp of size M24. At the same time, a smooth arc is used as the transition section between the gauge length section and the clamping section, so that each arc is tangent to the plane of each gauge length section. The 3D model of the simulated part is as follows: Figure 5 As shown, gauge length section 1, clamping section 2 and transition section 3 are integrated into one design, wherein the shape and size of gauge length section 1 are the same as the shape and size of the oblique hole after equivalent simplification.

[0054] In steps six and ten, the parallel offset positions and parallel offset distances between the central axes of the two clamping segments and the geometric central axis of the gauge segment in the simulation model are adjusted so that the two central axes are parallel but not coaxial.

[0055] In step nine, a low-cycle fatigue testing machine is used to perform a low-cycle fatigue test on the simulated part, and a rotational fatigue testing machine is used to perform a rotational fatigue test on the simulated workpiece; the loading method of the low-cycle fatigue testing machine is a vertical tensile-compressive loading.

[0056] After the above-mentioned repeated design and adjustments, in this embodiment, when the geometric center of the circular cross-section of the clamping section deviates from the geometric center of the trapezoidal cross-section of the gauge length section by X = 0.094 mm and Y = 1.453 mm, the stress-strain distribution and failure location of the simulated part are consistent with those of the workpiece to be simulated. The final stress gradient distribution and strain gradient distribution of the simulated part under the linear elasticity method and the elastoplasticity method are as follows: Figure 6 and Figure 7 As shown.

[0057] This embodiment presents a design method for a simulated component used to predict the low-cycle fatigue performance of an engine disk. It is simple, convenient, and easy to operate. Through structural simplification and finite element simulation, the method analyzes the elastic stress, elastic strain, plastic stress, plastic strain, and stress-strain distribution of the simulated component. It then adjusts the equivalent loading position and equivalent load of the simulated component to achieve the fatigue failure mode and location of the workpiece being simulated, thereby simulating the stress state of the critical structural features of the disk. Finally, a performance-based fatigue test is conducted on the simulated component in a laboratory environment. Since this design method only involves rationalizing the equivalent loading position and equivalent load without redesigning the structural features and dimensions, the test results can be used to predict the disk's lifespan and directly assess its safety under specific operating conditions.

[0058] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0059] Those skilled in the art will readily understand that the design method for the simulation component used to predict the low-cycle fatigue performance of an engine disk according to the present invention includes any combination of the inventive summary and specific embodiments described in the above specification and the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a simulation component used to predict the low-cycle fatigue performance of an engine disk, comprising the following steps in sequence: Step 1: Based on the actual condition of the workpiece to be simulated, extract the structural features and their corresponding dimensions on the workpiece. Step 2: Based on the extracted structural features and their corresponding dimensions, the stress state of the structural features is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software, respectively, to obtain the stress gradient distribution and strain gradient distribution of the structural features under the simulation of the two mechanical methods. Step 3: Perform equivalent simplification on the structural features that are adjacent to or near the extracted structural features and have no obvious structural strength relationship with them, as well as their corresponding structural feature dimensions. The structural features after equivalent simplification have the same shape and size as the workpiece to be simulated. Step 4: Design the simulation model. The structural features after equivalent simplification are used as the gauge length of the simulation part. The cylinder with threads on the outer surface is used as the two clamping sections of the simulation part. The two clamping sections are smoothly connected to the two ends of the gauge length section through transition sections. The central axis of the two clamping sections coincides with the geometric central axis of the gauge length section. Step 5: Based on the simulated part model, use the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software to analyze the stress state of the simulated part, and obtain the stress gradient distribution and strain gradient distribution of the simulated part under the simulation of the two mechanical methods, and compare them with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods. Step Six: Based on the comparison results of the stress gradient distribution and strain gradient distribution under the two mechanical methods, if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then the design of the simulated part model is completed; if the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are inconsistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods, then it is necessary to adjust the parallel offset position and parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge length segment in the simulated part model. Step 7: Based on the adjusted simulation model, the stress state of the simulation component is analyzed using the linear elastic mechanics method and the elastoplastic mechanics method in the finite element simulation software. The stress gradient distribution and strain gradient distribution of the simulation component under the simulation of the two mechanical methods are obtained respectively, and compared with the stress gradient distribution and strain gradient distribution of the structural features obtained in Step 2 under the simulation of the two mechanical methods. Step 8: Repeat steps 6 and 7 until the stress gradient distribution and strain gradient distribution of the simulated part under the two mechanical methods are consistent with the stress gradient distribution and strain gradient distribution of the structural features under the two mechanical methods. The design of the simulated part model is then complete. Step 9: Fabricate a simulated part based on the simulated part model and conduct low-cycle fatigue tests on it to obtain the low-cycle fatigue performance test results of the simulated part; at the same time, conduct a rotational fatigue test on the workpiece to be simulated to obtain the low-cycle fatigue performance test results of the workpiece to be simulated. Step 10: Compare the low-cycle fatigue performance test results of the simulated part with those of the workpiece to be simulated. If the fatigue failure location and mode of the simulated part are consistent with those of the workpiece to be simulated, the design of the simulated part is completed. If the fatigue failure location and mode of the simulated part are inconsistent with those of the workpiece to be simulated, the parallel offset position and the parallel offset distance between the central axis of the two clamping segments and the geometric central axis of the gauge segment in the simulated part model need to be readjusted. Step 11: Repeat steps 7 to 10 until the fatigue failure location and mode of the simulated part are consistent with the fatigue failure location and mode of the workpiece to be simulated. This completes the design of the simulated part used to predict the low-cycle fatigue performance of the engine disk.

2. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 1, characterized in that: In step one, the workpiece to be simulated is a wheel disc type part of an aircraft engine. The structural features include any one or more of the following: small hole, chamfer, transition arc, tilt angle, sector and annulus. The dimensions of the structural features include any one or more of the following: radius, diameter, arc length and angle.

3. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 2, characterized in that: In step four, the gauge section, clamping section and transition section of the simulation part are designed as an integrated unit. The thread size of the outer surface of the clamping section needs to be determined according to the actual capacity of the low-cycle fatigue testing machine and the thread size of the corresponding clamping fixture.

4. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 3, characterized in that: In step four, while designing the simulation model, it is necessary to determine the equivalent loading position and equivalent load of the simulation component; the equivalent loading position of the simulation component is adjusted in the horizontal plane, and the magnitude of the equivalent load is adjusted at the same time.

5. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 4, characterized in that: In steps six and ten, the parallel offset positions and parallel offset distances between the central axes of the two clamping segments and the geometric central axis of the gauge segment in the simulation model are adjusted so that the two central axes are parallel but not coaxial.

6. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 5, characterized in that: In step nine, a low-cycle fatigue testing machine is used to perform a low-cycle fatigue test on the simulated part, and a rotational fatigue testing machine is used to perform a rotational fatigue test on the simulated workpiece; the loading method of the low-cycle fatigue testing machine is a vertical tensile-compressive loading.

7. The design method for a simulation component for predicting the low-cycle fatigue performance of an engine disk according to claim 6, characterized in that: The finite element simulation software includes any one or more of Abaqus, Ansys, MSC.Marc, and Isight. The finite element simulation software is used to calculate and analyze the structural features and the stress state of the simulated component. The stress state includes any one or more of elastic stress, elastic strain, plastic stress, plastic strain, and stress-strain distribution.

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