A method and device for simplified modeling of the dynamics of an engine interstage elastic support structure
By using the equal volume equivalent method and radial stiffness attenuation coefficient calculation, an equivalent beam element model suitable for rotor dynamics analysis is established. This solves the problem that existing methods cannot fully consider the discontinuous shaft segments of the interstage elastic support structure, enabling more accurate assessment of critical speed and strain energy distribution, and supporting overall engine dynamics optimization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AECC SHENYANG ENGINE RES INST
- Filing Date
- 2026-02-27
- Publication Date
- 2026-06-02
AI Technical Summary
Existing rotor dynamics analysis methods cannot fully consider the circumferential discontinuous shaft segments of the interstage elastic support structure of the engine, resulting in inaccurate calculation of critical speed and evaluation of strain energy distribution characteristics.
The equivalent density of the elastic shaft segment is determined by the equal volume equivalent method, and the equivalent elastic modulus is calculated by the radial stiffness attenuation coefficient. An equivalent beam element model suitable for rotor dynamics analysis is established and coupled with the whole machine dynamics model.
A high-fidelity model of the whole rotor dynamics was established, which improved the accuracy of critical speed calculation and the evaluation of strain energy distribution characteristics, and guided the overall dynamic optimization design.
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Figure CN122133258A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of engine modeling technology, specifically relating to a simplified modeling method and apparatus for the dynamics of an engine interstage elastic support structure. Background Technology
[0002] As aero-engines develop towards higher thrust, the design speeds of the high- and low-pressure rotors in dual-rotor systems are continuously increasing. This necessitates the design of an interstage elastic support structure between the high- and low-pressure rotor stages to adjust the critical speed and ensure a rational overall engine structural design. The interstage elastic support structure is bolted to the low-pressure rotor and rotates with it. It is connected to the high-pressure turbine disk of the high-pressure rotor via interstage bearings. Typically, the stiffness of the elastic shaft section of this interstage elastic support structure is reduced by machining square holes and removing material. Figure 1 As shown, this measure causes the interstage elastic support shaft segment to become a circumferentially discontinuous shaft segment. Currently, mature 1D and 2D rotor dynamics analysis methods usually cannot fully consider the establishment of a rotor dynamics model for this special structure. They can only simplify the stiffness weakening effect of this elastic shaft segment into the support stiffness model, which has an adverse effect on the calculation of critical speed and the evaluation of strain energy distribution characteristics.
[0003] To establish a high-fidelity whole-machine rotor dynamics model, it is necessary to establish an equivalent simplified rotor dynamics model that considers the non-complete axisymmetric elastic shaft segment to ensure a reasonable evaluation of the dynamic characteristics of the rotor-support system. A simplified modeling method for the dynamics of the interstage elastic support structure of a dual-rotor engine is proposed, and a simplified method for the mechanical performance parameters of the circumferentially discontinuous elastic shaft segment is given. An equivalent dynamics model of the elastic shaft segment suitable for 1D / 2D analysis of rotor dynamics is established, which can effectively guide the optimization design of the whole-machine dynamics. Summary of the Invention
[0004] To address the aforementioned issues, it is necessary to establish a high-fidelity whole-machine rotor dynamics model that can consider the equivalent rotor dynamics of the non-fully axisymmetric elastic shaft segment, ensuring a reasonable evaluation of the dynamic characteristics of the rotor-support system. To this end, this application provides a simplified modeling method and apparatus for the dynamics of the interstage elastic support structure of an engine.
[0005] The first aspect of this application provides a simplified modeling method for the dynamics of an interstage elastic support structure in an engine, mainly including:
[0006] Step S1: Based on the dimensional parameters of the elastic shaft segment of the elastic support structure, determine the equivalent density of the elastic shaft segment using the equal volume equivalent method;
[0007] Step S2: Determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure;
[0008] Step S3: According to the size parameters of the elastic shaft segment of the elastic support structure, the elastic shaft segment is equivalently represented by an equivalent beam element, and the equivalent density parameter and equivalent elastic modulus parameter are assigned to the equivalent beam element.
[0009] Step S4: Establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model to complete the establishment of the whole machine rotor dynamics model.
[0010] Preferably, in step S1, the equivalent density of the elastic shaft segment is determined using the following formula. :
[0011] ;
[0012] in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
[0013] Preferably, in step S2, the equivalent elastic modulus of the elastic shaft segment is determined using the following formula. :
[0014] ;
[0015] in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
[0016] Preferably, the radial stiffness attenuation coefficient of the elastic support structure is obtained by calculating the ratio of the nominal stiffness value of the elastic support structure calculated by three-dimensional finite element method to the nominal stiffness value of the support structure without square holes calculated by three-dimensional finite element method.
[0017] The second aspect of this application provides a simplified modeling device for the dynamics of an interstage elastic support structure of an engine, mainly comprising:
[0018] The equivalent density determination module is used to determine the equivalent density of the elastic shaft segment based on the size parameters of the elastic shaft segment of the elastic support structure using the equal volume equivalent method.
[0019] The equivalent elastic modulus determination module is used to determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure.
[0020] The equivalent beam element construction module is used to construct an equivalent beam element for the elastic shaft segment according to the dimensional parameters of the elastic shaft segment of the elastic support structure, and to assign equivalent density parameters and equivalent elastic modulus parameters to the equivalent beam element.
[0021] The rotor dynamics model establishment module is used to establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model, thereby completing the establishment of the whole machine rotor dynamics model.
[0022] Preferably, in the equivalent density determination module, the equivalent density of the elastic shaft segment is determined by the following formula. :
[0023] ;
[0024] in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
[0025] Preferably, in the equivalent elastic modulus determination module, the equivalent elastic modulus of the elastic shaft segment is determined by the following formula. :
[0026] ;
[0027] in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
[0028] Preferably, the radial stiffness attenuation coefficient of the elastic support structure is obtained by calculating the ratio of the nominal stiffness value of the elastic support structure calculated by three-dimensional finite element method to the nominal stiffness value of the support structure without square holes calculated by three-dimensional finite element method.
[0029] Starting from the density and elastic modulus parameters of the model material, this application proposes an equivalent density calculation method based on the same volume theory. At the same time, it proposes a method for obtaining the stiffness attenuation coefficient based on the finite element analysis of the actual three-dimensional model. On this basis, it gives a method for calculating the equivalent elastic modulus and establishes an equivalent beam element model of the circumferential discontinuous shaft segment suitable for rotor dynamics analysis, which ensures the accuracy of the whole machine rotor dynamics analysis and the rationality of the rotor dynamics structure optimization design direction. Attached Figure Description
[0030] Figure 1This is a schematic diagram of the square hole in the elastic shaft section of the elastic support structure.
[0031] Figure 2 This is a flowchart of a preferred embodiment of the simplified modeling method for the dynamics of the interstage elastic support structure of the engine in this application. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0033] This application provides a simplified modeling method for the dynamics of interstage elastic support structures in engines, such as... Figure 2 As shown, it mainly includes:
[0034] Step S1: Based on the dimensional parameters of the elastic shaft segment of the elastic support structure, determine the equivalent density of the elastic shaft segment using the equal volume equivalent method;
[0035] Step S2: Determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure;
[0036] Step S3: According to the size parameters of the elastic shaft segment of the elastic support structure, the elastic shaft segment is equivalently represented by an equivalent beam element, and the equivalent density parameter and equivalent elastic modulus parameter are assigned to the equivalent beam element.
[0037] Step S4: Establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model to complete the establishment of the whole machine rotor dynamics model.
[0038] In step S1, it is first necessary to identify the geometric dimensions of the circumferential discontinuous elastic shaft segment, including the length, inner diameter, outer diameter, remaining cage bar width, and width of the square hole after material removal. The full-size geometric outline is established according to the completely axisymmetric shaft segment, and then the equivalent density of the elastic shaft segment is calculated.
[0039] In some alternative implementations, in step S1, the equivalent density of the elastic shaft segment is determined using the following formula. :
[0040] ;
[0041] in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
[0042] Then, in step S2, the equivalent elastic modulus of the elastic shaft segment is obtained.
[0043] In some alternative implementations, in step S2, the equivalent elastic modulus of the elastic shaft segment is determined using the following formula. :
[0044] ;
[0045] in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
[0046] In some alternative embodiments, the radial stiffness attenuation coefficient of the elastic support structure is calculated by the ratio of the nominal value of the stiffness of the elastic support structure calculated by three-dimensional finite element method to the nominal value of the stiffness of the support structure without square holes calculated by three-dimensional finite element method.
[0047] In this embodiment, it is necessary to establish a full three-dimensional analysis model of the inter-stage elastic support structure and a full three-dimensional analysis model of the inter-stage support structure without square holes. By setting boundary conditions and using the finite element simulation method, the radial stiffness of the support in the two models is calculated respectively, thereby obtaining the radial stiffness attenuation coefficient of the inter-stage elastic support structure. ,in, , To calculate the nominal stiffness of the interstage support structure without square holes using three-dimensional finite element analysis, The nominal stiffness value of the interstage elastic support structure is calculated using three-dimensional finite element method.
[0048] Next, in step S3, an equivalent beam element model with equivalent solid features is established. In the rotor dynamics analysis module, an equivalent beam element model suitable for rotor dynamics analysis is established according to the obtained interstage elastic support geometric parameters, equivalent density parameters, and equivalent elastic modulus parameters. Finally, in step S4, the established equivalent beam element model is coupled with the whole machine dynamics model to complete the establishment of the whole machine rotor dynamics model.
[0049] The second aspect of this application provides a simplified modeling device for the dynamics of an interstage elastic support structure of an engine, corresponding to the above method, mainly comprising:
[0050] The equivalent density determination module is used to determine the equivalent density of the elastic shaft segment based on the size parameters of the elastic shaft segment of the elastic support structure using the equal volume equivalent method.
[0051] The equivalent elastic modulus determination module is used to determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure.
[0052] The equivalent beam element construction module is used to construct an equivalent beam element for the elastic shaft segment according to the dimensional parameters of the elastic shaft segment of the elastic support structure, and to assign equivalent density parameters and equivalent elastic modulus parameters to the equivalent beam element.
[0053] The rotor dynamics model establishment module is used to establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model, thereby completing the establishment of the whole machine rotor dynamics model.
[0054] In some alternative embodiments, the equivalent density determination module determines the equivalent density of the elastic shaft segment using the following formula. :
[0055] ;
[0056] in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
[0057] In some alternative embodiments, the equivalent elastic modulus determination module determines the equivalent elastic modulus of the elastic shaft segment using the following formula. :
[0058] ;
[0059] in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
[0060] In some alternative embodiments, the radial stiffness attenuation coefficient of the elastic support structure is calculated by the ratio of the nominal value of the stiffness of the elastic support structure calculated by three-dimensional finite element method to the nominal value of the stiffness of the support structure without square holes calculated by three-dimensional finite element method.
[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A simplified modeling method for the dynamics of an interstage elastic support structure in an engine, characterized in that, include: Step S1: Based on the dimensional parameters of the elastic shaft segment of the elastic support structure, determine the equivalent density of the elastic shaft segment using the equal volume equivalent method; Step S2: Determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure; Step S3: According to the size parameters of the elastic shaft segment of the elastic support structure, the elastic shaft segment is equivalently represented by an equivalent beam element, and the equivalent density parameter and equivalent elastic modulus parameter are assigned to the equivalent beam element. Step S4: Establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model to complete the establishment of the whole machine rotor dynamics model.
2. The simplified modeling method for the dynamics of the interstage elastic support structure of an engine according to claim 1, characterized in that, In step S1, the equivalent density of the elastic shaft segment is determined using the following formula. : ； in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
3. The simplified modeling method for the dynamics of the interstage elastic support structure of an engine according to claim 1, characterized in that, In step S2, the equivalent elastic modulus of the elastic shaft segment is determined using the following formula. : ； in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
4. The simplified modeling method for the dynamics of the interstage elastic support structure of an engine according to claim 3, characterized in that, The radial stiffness attenuation coefficient of the elastic support structure is obtained by comparing the nominal stiffness value calculated by the three-dimensional finite element method of the elastic support structure with the nominal stiffness value calculated by the three-dimensional finite element method of the support structure without square holes.
5. A simplified modeling device for the dynamics of an engine interstage elastic support structure, characterized in that, include: The equivalent density determination module is used to determine the equivalent density of the elastic shaft segment based on the size parameters of the elastic shaft segment of the elastic support structure using the equal volume equivalent method. The equivalent elastic modulus determination module is used to determine the equivalent elastic modulus of the elastic shaft segment based on the radial stiffness attenuation coefficient of the elastic support structure. The equivalent beam element construction module is used to construct an equivalent beam element for the elastic shaft segment according to the dimensional parameters of the elastic shaft segment of the elastic support structure, and to assign equivalent density parameters and equivalent elastic modulus parameters to the equivalent beam element. The rotor dynamics model establishment module is used to establish a coupling relationship between the established equivalent beam element model and the whole machine dynamics model, thereby completing the establishment of the whole machine rotor dynamics model.
6. The simplified modeling device for the dynamics of the interstage elastic support structure of an engine according to claim 5, characterized in that, In the equivalent density determination module, the equivalent density of the elastic shaft segment is determined using the following formula. : ； in, The material density of the elastic support structure, The number of square holes for removing material from the elastic shaft segment of the elastic support structure. To remove the circumferential width of the square hole in the material. To remove the radial height of the square hole in the material, The outer radius of the elastic shaft segment, The inner radius of the elastic shaft segment.
7. The simplified modeling device for the dynamics of the interstage elastic support structure of an engine according to claim 5, characterized in that, In the equivalent elastic modulus determination module, the equivalent elastic modulus of the elastic shaft segment is determined by the following formula. : ； in, This is the radial stiffness attenuation coefficient of the elastically supported structure. This represents the elastic modulus of the original material of the elastic support structure.
8. The simplified modeling device for the dynamics of the interstage elastic support structure of an engine according to claim 7, characterized in that, The radial stiffness attenuation coefficient of the elastic support structure is obtained by comparing the nominal stiffness value calculated by the three-dimensional finite element method of the elastic support structure with the nominal stiffness value calculated by the three-dimensional finite element method of the support structure without square holes.