Design method and design equipment for strength of squirrel-cage integrated elastic support structure of aero-engine rotor system and computer readable storage medium

Abstract

The invention relates to an aero-engine rotor system squirrel-cage integrated elastic support structure strength design method and design equipment and a computer readable storage medium. The strength design method for the squirrel-cage integrated elastic support structure of the aero-engine rotor system comprises the steps that S1, rigidity analysis and static strength analysis are conducted on a squirrel-cage integrated elastic support; s2, arranging a strain gauge and a force measuring ring according to a static strength analysis result; s3, establishing a Goodman curve based on the material characteristics of the squirrel-cage integrated missile support, and obtaining the corresponding maximum stress amplitude sigma limit on the Goodman curve based on the real stress mean value sigma x; s4, judging whether an infinite life criterion is met or not; s5, carrying out life analysis on the squirrel-cage integrated elastic support structure based on the stress-life curve; and S6, ending. The invention provides an aero-engine rotor system squirrel-cage integrated elastic support structure strength design method and design equipment and a computer readable storage medium. The service life of an elastic support structure can be evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine manufacturing, and in particular to a strength design method, design equipment and computer-readable storage medium for a squirrel-cage integrated spring support structure of an aero-engine rotor system. Background Art

[0002] The squirrel cage spring is a common elastic support structure for aircraft engines. It has the functions of adjusting the critical speed of the system, changing the strain energy distribution and absorbing vibration energy. In the lightweight design of aircraft engines, rod bearings and ball bearing springs are usually integrated into one. The squirrel cage integrated spring is subjected to the alternating load generated by the rotation of the rotor. The magnitude and direction of this load changes with the rotation of the rotor, which is called eddy load. It also bears the axial aerodynamic load transmitted by the rotor through the ball bearing. The existing simulation methods cannot obtain accurate stress distribution and cannot evaluate the life of the spring. Therefore, it is urgent to propose a new strength design method for squirrel cage integrated springs. Summary of the invention

[0003] In view of the above problems in the prior art, the present invention proposes a strength design method, design equipment and computer-readable storage medium for a squirrel-cage integrated spring support structure of an aircraft engine rotor system, which can perform life assessment on the spring support structure.

[0004] Specifically, the present invention proposes a strength design method for a squirrel cage integrated spring support structure of an aero-engine rotor system, comprising the following steps:

[0005] S1, according to the integrated design of the squirrel cage elastic support structure, combined with finite element calculation, the stiffness analysis and static strength analysis of the squirrel cage integrated elastic support are carried out respectively, the stiffness of the ball bearing elastic support structure and the roller bearing elastic support structure are obtained through the stiffness analysis, and the stress amplitude and stress mean of the squirrel cage integrated elastic support are obtained through the static strength analysis;

[0006] S2, according to the static strength analysis results, strain gauges are arranged on the squirrel cage integrated spring support to obtain the true stress amplitude at the maximum stress of the squirrel cage integrated spring support; a force measuring ring is installed between the bearing mounting surface and the squirrel cage integrated spring support, and a strain gauge is arranged on the force measuring ring to obtain the linear relationship between the axial force strain response value and the axial force, and the axial force mean value is obtained based on the linear relationship, and the true stress mean value σ of the squirrel cage integrated spring support is obtained by combining the finite element calculation. x ;

[0007] S3, based on the material properties of the squirrel cage integrated spring support, the Goodman curve is established based on the true stress mean σ x Get the corresponding maximum stress amplitude σ on the Goodman curve lim it ;

[0008] S4, according to the maximum stress amplitude σlim it The maximum test strain value ε in the true stress amplitude obtained in step S2 is test , determine whether the conditions are met:

[0009]

[0010] Among them, the stress σ at two locations obtained by finite element calculation in step S1 is sim2 and σ sim1 The ratio represents the calculated stress gradient, and E represents the elastic modulus of the material;

[0011] If the condition is met, the squirrel cage integrated spring meets the infinite life criterion, and the process goes to step S6; if not, the process goes to step S5;

[0012] S5, life analysis of squirrel cage integrated spring support structure based on stress-life curve;

[0013] S6, end.

[0014] According to one embodiment of the present invention, in step S1, the stiffness analysis includes the steps of:

[0015] Sa1, assign corresponding material properties to the elastic support structure in Ansys Workbench;

[0016] Sa2, constrains the axial and circumferential freedom of the squirrel cage integrated spring support flange surface and the radial freedom of the installation stop position;

[0017] Sa3, using high-order elements to perform finite element meshing of squirrel cage integrated springs;

[0018] Sa4, using the flexible distal end point method to associate the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively, and applying a radial unit load Fr at the distal end positions of the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively;

[0019] Sa5, the radial displacements dr1 and dr2 of the distal end points of the outer rings of the ball bearing and the roller bearing are measured, and the stiffness K1 and K2 of the elastic support structure of the ball bearing and the roller bearing are obtained. The calculation formulas of the stiffness K1 and K2 are:

[0020]

[0021] Sa6, compare the stiffness K1 and K2 with the aircraft engine overall strength requirement K to verify that the stiffness of the squirrel cage integrated support structure meets the overall strength requirement.

[0022] According to one embodiment of the present invention, in step S1, the static strength analysis includes the steps of:

[0023] Sb1, assign corresponding material properties to the elastic support structure in Ansys Workbench;

[0024] Sb2, constrains the axial and circumferential degrees of freedom of the integrated spring-loaded support flange surface and the radial degrees of freedom of the mounting stop position, uses the flexible distal end point method to associate the roller bearing outer ring mounting surface and the ball bearing outer ring mounting surface, and simultaneously applies a radial displacement d1 at the distal end point of the roller bearing outer ring mounting surface and the ball bearing outer ring mounting surface position to obtain the stress amplitude σa of the squirrel cage integrated spring-loaded support structure;

[0025] Sb3, constrain the axial and circumferential degrees of freedom of the integrated spring-supported flange surface and the radial degrees of freedom of the mounting stop position, use the flexible distal point method to associate the ball bearing outer ring mounting surface, apply the axial force F on the distal point, and obtain the stress mean σm;

[0026] Sb4, the stress amplitude σa and the stress mean σm are superimposed as the static strength analysis result.

[0027] According to one embodiment of the present invention, in step S2, if the maximum stress obtained by the static strength analysis is located at the cage bar of the elastic support structure, a strain gauge is arranged at the maximum stress location to measure the maximum stress σ max If the maximum stress obtained by analysis is located at the fillet of the spring-supported cage bar, the strain gauge is arranged in the middle of the corresponding cage bar to obtain the test strain value ε test , based on the test strain value ε test Calculate the maximum stress σ max .

[0028] According to one embodiment of the present invention, by testing the strain value ε test Get the true strain value ε at the maximum stress max The calculation formula is:

[0029]

[0030] Through the true strain value ε max The true maximum stress σ is calculated max The calculation formula is:

[0031] σ max =E·ε max .

[0032] According to an embodiment of the present invention, in step S2, three strain gauges are arranged on the force measuring ring as measuring points, and the circumferential positions of the three strain gauges are 120° to each other and are located on the same cross section.

[0033] According to one embodiment of the present invention, a linear relationship between the axial force-strain response value and the axial force is obtained through a combined calibration test.

[0034] According to one embodiment of the present invention, in step S3, the maximum stress amplitude σ satisfying the infinite life criterion is obtained according to the Goodman curve. lim it The formula is:

[0035] σ limit =σ -1 +σ -1 σ x / σ b ;

[0036] Among them, σ -1 is the yield strength property of the squirrel cage support material, σ b is the tensile strength property of the squirrel cage spring material.

[0037] According to one embodiment of the present invention, in step S2, the static strength analysis result in step S1 is verified by the true stress amplitude and the true stress mean.

[0038] According to one embodiment of the present invention, in step S5, the symmetrical cyclic stress S is calculated according to the Goodman formula e , Goodman's formula is:

[0039]

[0040] Among them, σ b is the tensile strength of the material, S a is the stress amplitude, S m is the stress mean, the stress amplitude S a is the stress under the radial displacement da in step S2, and the stress mean S m is the stress under the action of the axial force Fm in step S2, and must be the stress at the same point;

[0041] According to the stress-life curve of a given material, according to the symmetrical cyclic stress S e The life N of the squirrel cage integrated spring support structure is calculated.

[0042] The present invention also provides a strength design device for a squirrel-cage integrated spring-loaded support structure of an aero-engine rotor system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned strength design methods for a squirrel-cage integrated spring-loaded support structure of an aero-engine rotor system when executing the computer program.

[0043] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the strength design method of a squirrel-cage integrated spring support structure of an aircraft engine rotor system described in any of the above items are implemented.

[0044] The present invention provides a strength design method, design equipment and computer-readable storage medium for a squirrel-cage integrated spring-support structure of an aero-engine rotor system. The method guides a test strain gauge pasting scheme through finite element calculation, and then corrects the finite element calculation results with actual measurement values, and performs a life assessment of the spring-support structure.

[0045] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are included to provide further explanation of the present invention, and are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principle of the present invention.

[0047] In the attached figure:

[0048] Figure 1 A flowchart of a method for designing the strength of a squirrel-cage integrated spring support structure of an aircraft engine rotor system according to an embodiment of the present invention is shown.

[0049] Figure 2 A schematic diagram of strain gauge pasting according to an embodiment of the present invention is shown.

[0050] Figure 3 yes Figure 2 Top view of the .

[0051] Figure 4 A schematic diagram of the installation of a force measuring ring according to an embodiment of the present invention is shown.

[0052] Figure 5 A schematic diagram showing a method of pasting a strain gauge on a force measuring ring according to an embodiment of the present invention is shown.

[0053] Figure 6 A schematic diagram of a Goodman curve according to an embodiment of the present invention is shown.

[0054] Figure 7 A stress-life curve for a given material is shown for one embodiment of the present invention. DETAILED DESCRIPTION

[0055] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0056] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0057] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0058] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0059] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0060] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0061] Figure 1 A flowchart of a method for designing the strength of a squirrel cage integrated spring-loaded support structure of an aircraft engine rotor system according to an embodiment of the present invention is shown. As shown in the figure, the present invention provides a method for designing the strength of a squirrel cage integrated spring-loaded support structure of an aircraft engine rotor system, comprising the following steps:

[0062] S1, according to the integrated design of the squirrel cage spring support structure, combined with finite element calculation, the stiffness analysis and static strength analysis of the squirrel cage integrated spring support are carried out respectively. Among them, the stiffness of the ball bearing spring support structure and the roller bearing spring support structure are obtained through stiffness analysis to verify whether they meet the strength requirements of the whole machine. The stress amplitude and stress mean of the squirrel cage integrated spring support are obtained through static strength analysis.

[0063] S2, according to the results of static strength analysis, strain gauges are arranged on the squirrel cage integrated spring support to obtain the true stress amplitude at the maximum stress of the squirrel cage integrated spring support. A force ring is installed between the bearing mounting surface and the squirrel cage integrated spring support, and strain gauges are arranged at the measuring points on the force ring to obtain the linear relationship between the axial force strain response value and the axial force at each measuring point. Based on this linear relationship, the mean axial force is obtained, and the true stress mean σ of the squirrel cage integrated spring support is obtained by combining finite element calculation. x .

[0064] S3, based on the material properties of the squirrel cage integrated spring support, the Goodman curve is established based on the true stress mean σ x Find the corresponding maximum stress amplitude σ on the Goodman curve lim it .

[0065] S4, according to the maximum stress amplitude σ lim it The maximum test strain value ε in the true stress amplitude obtained in step S2 is test , determine whether the two conditions are met:

[0066]

[0067] Among them, the stress σ at two locations obtained by finite element calculation in step S1 is sim2 and σsim1 The ratio represents the calculated stress gradient, and E represents the elastic modulus of the material;

[0068] If the condition is met, the squirrel cage integrated spring meets the infinite life criterion, and no subsequent life analysis is required, and the process goes to step S6. If not, the process goes to step S5;

[0069] S5, life analysis of squirrel cage integrated spring support structure based on stress-life curve;

[0070] S6, end.

[0071] Preferably, in step S1, the stiffness analysis includes the steps of:

[0072] Sa1, assign corresponding material properties to the elastic support structure in Ansys Workbench (co-simulation environment);

[0073] Sa2, constrains the axial and circumferential freedom of the squirrel cage integrated spring support flange surface and the radial freedom of the installation stop position;

[0074] Sa3, using high-order elements to perform finite element meshing of squirrel cage integrated springs;

[0075] Sa4, using the flexible distal end point method to associate the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively, and applying a radial unit load Fr at the distal end positions of the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively;

[0076] Sa5, the radial displacements dr1 and dr2 of the distal end points of the outer rings of the ball bearing and the roller bearing are measured, and the stiffness K1 and K2 of the elastic support structure of the ball bearing and the roller bearing are obtained. The calculation formulas of the stiffness K1 and K2 are:

[0077]

[0078] Sa6, compare the stiffness K1 and K2 with the aircraft engine strength requirement K to verify that the stiffness of the squirrel cage integrated spring support structure meets the strength requirement of the whole engine. Execute the subsequent steps on the premise of ensuring that the stiffness meets the strength requirement of the whole engine.

[0079] Preferably, in step S1, the static strength analysis includes the steps of:

[0080] Sb1, assign corresponding material properties to the elastic support structure in Ansys Workbench, including density, elastic modulus, Poisson's ratio, etc.;

[0081] Sb2, split the static strength analysis into stress amplitude analysis and stress mean analysis. Among them, the roller bearing elastic support structure only bears the effect of radial load during operation, and the ball bearing elastic support structure bears the combined effect of radial load and gas axial force during operation. Therefore, the axial and circumferential degrees of freedom of the integrated elastic support flange surface and the radial degrees of freedom of the mounting stop position are constrained, and the outer ring mounting surface of the roller bearing and the outer ring mounting surface of the ball bearing are associated using the flexible distal point method. The radial displacement d1 is applied simultaneously at the distal point of the outer ring mounting surface of the roller bearing and the outer ring mounting surface of the ball bearing, and the stress amplitude σa of the squirrel cage integrated elastic support structure is obtained.

[0082] Sb3, constrain the axial and circumferential degrees of freedom of the integrated spring-supported flange surface and the radial degrees of freedom of the mounting stop position, use the flexible distal point method to associate the ball bearing outer ring mounting surface, apply the axial force F on the distal point, and obtain the stress mean σm;

[0083] Sb4, the stress amplitude σa and the stress mean σm are superimposed as the static strength analysis result.

[0084] Figure 2 A schematic diagram of strain gauge pasting according to an embodiment of the present invention is shown. Figure 3 yes Figure 2 As shown in the figure, preferably, in step S2, if the maximum stress obtained by the static strength analysis is located at the cage bar 201 of the elastic support structure, a strain gauge 301 is arranged at the maximum stress position to measure the maximum stress σ max ;

[0085] If the maximum stress obtained by analysis is located at the fillet of the cage bar of the elastic support structure, for example, the place with the largest stress mean value is usually located at the fillet near the installation edge, the fillet at the bend, and the fillet at the far installation edge of the cage bar corresponding to the elastic support structure ball bearing, and the largest stress amplitude mainly occurs at the fillet near the installation edge, the fillet at the bend, and the fillet at the far installation edge of the cage bar corresponding to the ball bearing and rod bearing. Then arrange the strain gauge in the middle of the corresponding cage bar to obtain the test strain value ε test , based on the test strain value ε test Calculate the maximum stress σ max .

[0086] More preferably, the test strain value ε test Get the true strain value ε at the maximum stress max The calculation formula is:

[0087]

[0088] Through the true strain value ε max The true maximum stress σ is calculated max The calculation formula is:

[0089] σ max=E·ε max .

[0090] It should be noted that the dangerous positions of general elastic support structures are stress concentration positions such as small features and cross-sectional mutations. The results of the stiffness and static strength analysis of the elastic support structure obtained by the finite element analysis method in step S1 can determine the stress distribution diagram of the elastic support structure under axial and radial loads, that is, the stress and stress distribution at the dangerous position can be obtained by finite element simulation calculation. Finite element simulation calculation is to calculate the stress and stress distribution of the whole structure, which can determine the stress and stress distribution at the dangerous position of the structure.

[0091] In this embodiment, according to the load and installation condition of the squirrel cage integrated spring support structure, the stress distribution diagrams of the ball bearing and the roller bearing are calculated respectively through finite element analysis, and the dangerous positions of the squirrel cage integrated spring support are determined to be the fillet near the installation edge, the fillet at the bend, and the fillet far from the installation edge. The stress mean and stress amplitude of the dangerous positions are obtained, as shown in Table 1.

[0092] Table 1 Calculation results of stress at dangerous positions of squirrel cage elastic support structure

[0093] Location Cage bar near the installation edge rounded Cage bar bend radius Cage bar far installation edge rounded Mean stress (MPa) 191.46 394.56 383.99 Stress amplitude (MPa) 246.25 176.34 218.42

[0094] According to the actual size of the strain gauge and the specific configuration and size of the designed squirrel cage spring support, and in combination with the reasonable arrangement of the strain gauge 301 at the dangerous position determined in step S1, the number of strain gauges and the installation position are determined. As shown in the position diagram in Table 1, the dangerous positions in this embodiment are all at the rounded corners, so it is difficult to directly paste the strain gauges. Therefore, Figure 2 As shown, the spring-supported strain gauge 301 is along the direction of the cage bar 201, with a width located in the center of the cage bar 201 and pasted near the fillet. Figure 3 , along the axial viewing angle, two strain gauges 301 are symmetrically arranged in the horizontal and vertical directions to prevent failure of a strain gauge 301 and obtain the average strain value at the cage bar position.

[0095] Figure 4 A schematic diagram of the installation of a force measuring ring according to an embodiment of the present invention is shown. Figure 5 FIG. 1 is a schematic diagram showing a method of pasting a strain gauge on a force measuring ring according to an embodiment of the present invention. Figure 4 As shown, install a 30KN force ring 401 between the bearing mounting surface and the spring support. Figure 5, three strain gauges 301 are arranged on the force measuring ring as measuring points. The circumferential positions of the three strain gauges 301 are 120° to each other and are located on the same cross section. The linear relationship between the axial force strain response value and the axial force of each measuring point is obtained through a combined calibration test. Specifically, the combined calibration test is to use the three measuring points as three strain gauge groups, load them with an arithmetic sequence of 1KN, 2KN...22KN as loads, and obtain the corresponding strain signals. Three groups of tests are performed on each measuring point, and the mean of the three groups of strain values ​​is taken as x, and the load of the strain gauge group is taken as y, to obtain the linear relationship between the axial force strain response values ​​and the axial force of the three measuring points:

[0096] y=a1x+b1, y=a2x+b2, y=a3x+b3.

[0097] The time domain signal of the strain response value of each strain gauge 301 on the force measuring ring 401 is obtained. According to the linear relationship between the strain response value and the axial force, the time domain signal of the axial force can be obtained by conversion. The axial forces obtained by the three strain gauges 301 are averaged to reduce the error, and the mean value of the axial force in the time domain is obtained. The mean axial force is the actual axial force value measured in the test, and the actual stress mean value σ of the elastic support structure is calculated by combining the finite element method x The calculation method comprises the steps of:

[0098] S21, assign corresponding material properties to the elastic support structure in Ansys Workbench;

[0099] S22, since only the ball bearing is subjected to axial force, only the ball bearing is analyzed, and the flexible distal end point method is used to associate the ball bearing outer ring mounting surface, and the measured axial force mean is applied to the distal end point Get the true stress mean σ of the ball bearing x .

[0100] Figure 6 A Goodman curve schematic diagram of an embodiment of the present invention is shown. Preferably, in step S3, the material of the squirrel cage integrated spring adopts the characteristics of 15-5PH (martensitic precipitation hardening stainless steel), and the tensile strength σ of the material is extracted. b and the yield strength σ of the material -1 . refer to Figure 6 , connect the coordinates in the coordinate system (σ b ,0),(0,σ -1 ) to draw the Goodman curve. x Lock the horizontal axis and obtain the maximum stress amplitude σ that meets the infinite life criterion according to the Goodman curve limit The formula is:

[0101] σlimit =σ -1 +σ -1 σ x / σ b .

[0102] It is easy to understand that in step S2, the radial strain time domain signal εm measured by the strain gauge arranged on the squirrel cage integrated spring support is used to obtain the stress value σ according to the stress-strain relationship. m , if σ m Less than σ limit , the elastic support structure is considered to meet the infinite life criterion. If it does not meet the infinite life criterion, the system will alarm and record the excessive radial stress.

[0103] Preferably, in step S2, the static strength analysis result in step S1 is verified by the true stress amplitude and the true stress mean. The radial strain time domain signal εm is linearly related to the radial displacement dm at this time:

[0104] d m =A·ε m +C;

[0105] The radial displacement dm and the axial force mean As the modified boundary conditions, the stiffness and static strength of the squirrel cage integrated spring support are modified in combination with finite element calculation to obtain the modified stress distribution diagram. Combined with the modified stiffness and stress distribution diagram, it is evaluated whether the spring support meets the strength requirements.

[0106] Preferably, in step S5, the symmetrical cyclic stress S is calculated according to the Goodman formula e , Goodman's formula is:

[0107]

[0108] Among them, σ b is the tensile strength of the material, S a is the stress amplitude, that is, σ m , S m is the stress mean, that is, σ x , stress amplitude S a is the stress under the radial displacement da in step S2, and the stress mean S m It is the stress under the action of the axial force Fm in step S2, and it must be ensured to be the stress at the same point.

[0109] Figure 7 The stress-life curve of a given material of an embodiment of the present invention is shown, the horizontal axis represents the number of cycles, and the vertical axis represents the maximum fatigue strength. According to the stress-life curve of a given material, according to the symmetrical cyclic stress S e The life N of the squirrel cage integrated spring support structure is calculated.

[0110] The present invention also provides a strength design device for a squirrel-cage integrated spring-loaded support structure of an aircraft engine rotor system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any of the aforementioned strength design methods for a squirrel-cage integrated spring-loaded support structure of an aircraft engine rotor system are implemented.

[0111] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any of the aforementioned methods for designing the strength of a squirrel-cage integrated spring support structure of an aero-engine rotor system are implemented.

[0112] Among them, the specific implementation methods and technical effects of the design equipment and computer-readable storage medium can all be referred to the embodiment of the strength design method of the squirrel-cage integrated spring support structure of the aircraft engine rotor system provided by the present invention, and will not be repeated here.

[0113] The invention provides a method for designing the strength of a squirrel-cage integrated spring support structure of an aero-engine rotor system, a design device and a computer-readable storage medium, which have the following advantages:

[0114] 1. Combined with finite element analysis, the dangerous position of the elastic support structure is estimated to guide the design of the installation plan of the dynamic stress measurement point, which improves the problem that the maximum value of dynamic stress cannot be measured;

[0115] 2. The finite element calculation is corrected using the test measurement results to obtain more accurate stress distribution and stiffness values, further improving the accuracy of strength analysis;

[0116] 3. Combine the Goodman curve and simulation analysis results to provide reasonable limit values ​​for dynamic stress monitoring;

[0117] 4. The Goodman curve is used to determine whether the infinite life requirement is met, and the life assessment method when the infinite life requirement is not met is supplemented, thus improving the life assessment method of the elastic support structure.

[0118] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0119] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration.

[0120] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0121] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0122] It will be apparent to those skilled in the art that various modifications and variations may be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A strength design method for a squirrel cage integrated spring support structure of an aircraft engine rotor system, comprising the steps of: S1, according to the integrated design of the squirrel cage elastic support structure, combined with finite element calculation, the stiffness analysis and static strength analysis of the squirrel cage integrated elastic support are carried out respectively, the stiffness of the ball bearing elastic support structure and the roller bearing elastic support structure are obtained through the stiffness analysis, and the stress amplitude and stress mean of the squirrel cage integrated elastic support are obtained through the static strength analysis; S2, according to the static strength analysis results, strain gauges are arranged on the squirrel cage integrated spring support to obtain the true stress amplitude at the maximum stress of the squirrel cage integrated spring support; A force measuring ring is installed between the bearing mounting surface and the squirrel cage integrated spring support, and a strain gauge is arranged on the force measuring ring to obtain a linear relationship between the axial force strain response value and the axial force. Based on the linear relationship, the mean axial force value is obtained, and the true stress mean σ of the squirrel cage integrated spring support is obtained by combining finite element calculation. x ; S3, based on the material properties of the squirrel cage integrated spring support, the Goodman curve is established based on the true stress mean σ x Get the corresponding maximum stress amplitude σ on the Goodman curve lim it ; S4, according to the maximum stress amplitude σ lim it The maximum test strain value ε in the true stress amplitude obtained in step S2 is test , determine whether the conditions are met: Among them, the stress σ at two locations obtained by finite element calculation in step S1 is sim2 and σ sim1 The ratio represents the calculated stress gradient, and E represents the elastic modulus of the material; If the condition is met, the squirrel cage integrated spring meets the infinite life criterion, and the process goes to step S6; if not, the process goes to step S5; S5, life analysis of squirrel cage integrated spring support structure based on stress-life curve; S6, end.

2. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 1, characterized in that: In step S1, the stiffness analysis includes the steps of: Sa1, assign corresponding material properties to the elastic support structure in Ansys Workbench; Sa2, constrains the axial and circumferential freedom of the squirrel cage integrated spring support flange surface and the radial freedom of the installation stop position; Sa3, using high-order elements to perform finite element meshing of squirrel cage integrated springs; Sa4, using the flexible distal end point method to associate the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively, and applying a radial unit load Fr at the distal end positions of the ball bearing outer ring mounting surface and the roller bearing outer ring mounting surface respectively; Sa5, the radial displacements dr1 and dr2 of the distal end points of the outer rings of the ball bearing and the roller bearing are measured, and the stiffness K1 and K2 of the elastic support structure of the ball bearing and the roller bearing are obtained. The calculation formulas of the stiffness K1 and K2 are: Sa6, compare the stiffness K1 and K2 with the aircraft engine overall strength requirement K to verify that the stiffness of the squirrel cage integrated support structure meets the overall strength requirement.

3. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 2, characterized in that: In step S1, the static strength analysis includes the steps of: Sb1, assign corresponding material properties to the elastic support structure in Ansys Workbench; Sb2, constrains the axial and circumferential degrees of freedom of the integrated spring-loaded support flange surface and the radial degrees of freedom of the mounting stop position, uses the flexible distal end point method to associate the roller bearing outer ring mounting surface and the ball bearing outer ring mounting surface, and simultaneously applies a radial displacement d1 at the distal end point of the roller bearing outer ring mounting surface and the ball bearing outer ring mounting surface position to obtain the stress amplitude σa of the squirrel cage integrated spring-loaded support structure; Sb3, constrain the axial and circumferential degrees of freedom of the integrated spring-supported flange surface and the radial degrees of freedom of the mounting stop position, use the flexible distal point method to associate the ball bearing outer ring mounting surface, apply the axial force F on the distal point, and obtain the stress mean σm; Sb4, the stress amplitude σa and the stress mean σm are superimposed as the static strength analysis result.

4. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 3, characterized in that: In step S2, if the maximum stress obtained by static strength analysis is located at the cage bar of the elastic support structure, a strain gauge is arranged at the maximum stress location to measure the maximum stress σ max ; If the maximum stress obtained by analysis is located at the fillet of the spring-supported cage bar, the strain gauge is arranged in the middle of the corresponding cage bar to obtain the test strain value ε test , based on the test strain value ε test Calculate the maximum stress σ max .

5. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 4, characterized in that: The test strain value ε test Get the true strain value ε at the maximum stress max The calculation formula is: Through the true strain value ε max The true maximum stress σ is calculated max The calculation formula is: s max =E·e max 。 6. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 4, characterized in that: In step S2, three strain gauges are arranged on the force measuring ring as measuring points. The circumferential positions of the three strain gauges are 120° apart from each other and are located on the same cross section.

7. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 6, characterized in that: The linear relationship between the axial force-strain response value and the axial force is obtained through combined calibration tests.

8. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 4, characterized in that: In step S3, the maximum stress amplitude σ that satisfies the infinite life criterion is obtained according to the Goodman curve. lim it The formula is: s limit =s -1 +s -1 s x / s b ; Among them, σ -1 is the yield strength property of the squirrel cage support material, σ b is the tensile strength property of the squirrel cage spring support material.

9. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 4, characterized in that: In step S2, the static strength analysis result in step S1 is verified by the true stress amplitude and the true stress mean.

10. The strength design method of the squirrel cage integrated spring support structure of the aircraft engine rotor system according to claim 4, characterized in that: In step S5, the symmetrical cyclic stress S is calculated according to the Goodman formula e , Goodman's formula is: Among them, σ b is the tensile strength of the material, S a is the stress amplitude, S m is the stress mean, the stress amplitude S a is the stress under the radial displacement da in step S2, and the stress mean S m is the stress under the action of the axial force Fm in step S2, and must be the stress at the same point; According to the stress-life curve of a given material, according to the symmetrical cyclic stress S e The life N of the squirrel cage integrated spring support structure is calculated.

11. A strength design device for a squirrel cage integrated spring support structure of an aircraft engine rotor system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for strength design of squirrel-cage integrated spring support structure of an aircraft engine rotor system as described in any one of claims 1-10 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for strength design of squirrel-cage integrated spring support structure of an aircraft engine rotor system as described in any one of claims 1 to 10 are implemented.

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