A Stiffness Correction Method in the Dynamic Simulation Model of an Aeroengine Rotor Component

Abstract

This application belongs to the field of dynamic simulation of aero-engine rotor components, and specifically relates to a stiffness correction method in a dynamic simulation model of aero-engine rotor components, including: according to the connection form of the rotor structure system, gradually conducting rotor component modal tests from small systems to large systems to obtain the multi-order bending modal frequencies of the rotor components; establishing a dynamic simulation model of the rotor components and correcting its mass to match that of the test rotor components; based on the dynamic simulation model of the rotor components, analyzing the relationship between the multi-order bending modal frequencies of the rotor components and the elastic moduli of each rotor component and each connecting component; based on the corrected elastic modulus in the simulation model with a high correlation with the multi-order bending modal frequencies of the rotor component modal test, correcting the stiffnesses of each rotor in the dynamic simulation model of aero-engine rotor components; and correcting the stiffnesses of each support in the dynamic model of the rotor components based on the characteristics of the whole-engine test run dynamics.

Description

Technical Field

[0001] This application belongs to the field of dynamic simulation of aero-engine rotor components, and specifically relates to a stiffness correction method in a dynamic simulation model of aero-engine rotor components. Background Art

[0002] In the structural design stage of an aero-engine, good dynamic design is the basis for controlling the vibration response of the aero-engine and ensuring the safe operation of the engine. In dynamic design, the finite element simulation method is usually used for the analysis and optimization design of dynamic characteristics. Among them, the accuracy of the finite element model analysis results depends on whether the stiffness value setting of the rotor component is reasonable. The existing method for selecting the stiffness value is usually based on the empirical prediction method, resulting in a large deviation between the set stiffness and the actual stiffness. And usually, in order to ensure that the dynamic characteristics of the aero-engine can meet the index requirements, a large safety margin design is mostly adopted, resulting in a high design of the stiffness value, which in turn leads to a large overall mass of the aero-engine, reduces the thrust-to-weight ratio of the engine, and affects the engine performance.

[0003] In view of the existence of the above technical defects, this application is proposed.

[0004] It should be noted that the disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0005] The purpose of this application is to provide a stiffness correction method in a dynamic simulation model of aero-engine rotor components to overcome or mitigate at least one aspect of the known technical defects.

[0006] The technical solution of this application is: according to the connection form of the rotor component structure system, taking the principle that the structural stiffness correction parameters required each time do not exceed 2, gradually conduct rotor component modal tests from small systems to large systems, and gradually obtain the corrected stiffness values; then plan the engine full-load test run to obtain the dynamic characteristics under the full-load conditions, so as to further correct the equivalent support stiffness value in the dynamic simulation model of the rotor component;

[0007] A stiffness correction method in a dynamic simulation model of aero-engine rotor components includes:

[0008] Conduct rotor component modal tests to obtain the multi-order bending modal frequencies of the rotor component;

[0009] Establish a dynamic simulation model of the rotor component and correct its mass to be consistent with the mass of the rotor component;

[0010] Based on the dynamic simulation model of the rotor component, analyze the relationship between the multi-order bending mode frequencies of the rotor component and its elastic modulus;

[0011] Based on the modified elastic modulus in the simulation model with high correlation with the bending mode frequencies of each order in the modal test of the rotor component, correct the stiffness of each part of the rotor in the dynamic simulation model of the aero-engine rotor component.

[0012] Based on the characteristics of the dynamic performance during the overall engine test run, correct the equivalent stiffness of each support in the dynamic model of the rotor component;

[0013] According to at least one embodiment of the present application, in the stiffness correction method for the dynamic simulation model of the aero-engine rotor component, the rotor component has a slender shaft or sleeve teeth, and an arc end tooth connection structure.

[0014] According to at least one embodiment of the present application, in the stiffness correction method for the dynamic simulation model of the aero-engine rotor component, when conducting the modal test of the rotor component, the test piece used does not carry rotor blades.

[0015] According to at least one embodiment of the present application, the stiffness correction method for the dynamic simulation model of the aero-engine rotor component further includes:

[0016] According to the vibration data of the overall engine test run, obtain the actual critical speed of the fan in the old scheme. There is an existing aero-engine physical object, and the overall engine test run has been carried out. This aero-engine scheme is called the old scheme;

[0017] Analyze the relationship between the fan critical speed and its support stiffness to obtain the equivalent support stiffness of the fan support point;

[0018] Analyze the static stiffness of the fan bearing structure in the old scheme;

[0019] An aero-engine scheme derived from the old scheme, for which there is an existing aero-engine scheme but no aero-engine physical object, or there is an existing aero-engine physical object but the overall engine test run has not been carried out, is called the new scheme;

[0020] For the new scheme structure, obtain the static stiffness of its fan support bearing structure; for the new aero-engine scheme, under the condition of no overall engine test run results, compare the static stiffness values of the new scheme and the old scheme to obtain the flexibility difference, and use this flexibility difference to correct the equivalent support stiffness of the fan in the dynamic simulation model of the aero-engine rotor component.

[0021] The present application has at least the following beneficial technical effects:

[0022] Provided is a stiffness correction method in a dynamic simulation model of an aeroengine rotor component. When the mass in the dynamic simulation model of the aeroengine rotor component is corrected to match the mass of the rotor component, based on the modified elastic modulus in the simulation model that has a high correlation with the bending mode frequencies of each order in the modal test of the rotor component, the stiffnesses of each rotor in the dynamic simulation model of the aeroengine rotor component are corrected; based on the characteristics of the dynamic performance during the whole-engine test run, the support stiffnesses in the dynamic model of the rotor component are corrected. The stiffness in the dynamic simulation model of the aeroengine rotor component is corrected by combining tests and simulations. In addition, according to the critical speed of the fan obtained from the vibration data of the whole-engine test run, the equivalent support stiffness of the fan is inversely deduced. For the derivative new-engine design, the flexibility difference between the two schemes obtained by comparing the static stiffness simulation analysis results of the aeroengine support load-bearing structure is corrected. Finally, the analysis results of the dynamic simulation model of the aeroengine rotor component are made to match the vibration characteristics of the actual aeroengine test run, and the vibration characteristics of the high-precision engine can be accurately obtained before the whole new-engine design is completed. Description of the Drawings

[0023] Figure 1 FIG. is a schematic diagram of the stiffness correction method in the dynamic simulation model of the aeroengine rotor component provided by an embodiment of the present application, where the stiffness may include rotor stiffness and connection structure stiffness;

[0024] Figure 2 FIG. is a schematic diagram of the relationship between the critical speed of the fan and its equivalent support stiffness provided by an embodiment of the present application.

[0025] Figure 3 FIG. is a schematic diagram of obtaining the equivalent support stiffness of the new scheme in the above embodiment of the present application. Detailed Embodiments

[0026] To make the technical solutions of the present application and their advantages clearer, the technical solutions of the present application will be further described clearly and completely below with reference to the accompanying drawings. It can be understood that the specific embodiments described herein are only partial embodiments of the present application, which are only used to explain the present application and not to limit the present application. It should be noted that for the sake of description, only the parts related to the present application are shown in the drawings, and other related parts can refer to the general design. Without conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0027] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the ordinary meanings understood by those of ordinary skill in the art to which this application pertains. The words indicating directions such as "upper", "lower", "left", "right", "center", "vertical", "horizontal", "inner", "outer", etc. used in the description of this application are only used to indicate relative directions or positional relationships, rather than implying that the device or component must have a specific orientation, be constructed and operated in a specific orientation. When the absolute position of the object being described changes, its relative positional relationship may also change accordingly. Therefore, it should not be construed as a limitation to this application. The terms "first", "second", "third", and similar terms used in the description of this application are only for descriptive purposes to distinguish different components, and cannot be construed as indicating or implying relative importance. The similar words such as "a", "an", or "the" used in the description of this application should not be construed as an absolute limitation on the quantity, but should be understood as having at least one. The similar words such as "including" or "comprising" used in the description of this application are intended to indicate that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects.

[0028] In addition, it should also be noted that, unless otherwise clearly specified and limited, the similar words such as "installed", "connected", and "joined" used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can also be the communication inside two components. Those skilled in the art can understand its specific meaning in this application according to the specific situation.

[0029] The following combines the attached Figures 1 to 3 , and further elaborates on the stiffness correction method in the dynamic simulation model of the aero-engine rotor component provided by this application.

[0030] Prepare a test piece of the rotor component, conduct a modal test, and obtain at least the first two bending modal frequencies of the rotor component;

[0031] Establish a dynamic simulation model of the rotor component, with the mass error between it and the test piece within 1%;

[0032] Based on the dynamic simulation model of the rotor component, analyze and obtain at least the first two bending modal frequencies of the rotor component, analyze the relationship with its elastic modulus, and select a set of corresponding elastic moduli with high correlation with the modal frequencies of each order of the rotor component obtained from the modal test to correct the stiffness in the dynamic simulation model of the aero-engine rotor component, and try to make the frequency error of each order within 5%. If the correction does not meet the requirements for each order, at least ensure that the first-order bending is satisfied.

[0033] In an aero-engine, the low-pressure turbine shaft is slender, has weak stiffness, and is affected by many factors. Using the stiffness correction method in the aero-engine rotor component dynamics simulation model disclosed in the above example, the stiffness is corrected. In a specific example, its elastic modulus is determined to be 0.94, and the comparison of the multi-order bending mode frequencies obtained from the simulation analysis and the modal test is as follows in the table:

[0034]

[0035] In an aero-engine, a large axial pre-tightening force needs to be applied to the sleeve teeth and circular arc end teeth connection structure to achieve reliable connection. For this kind of connection structure relying on a large pre-tightening force, the loss of connection stiffness needs to be considered during the dynamic simulation. Using the stiffness correction method in the aero-engine rotor component dynamics simulation model disclosed in the above example, the stiffness is corrected. In a specific example, the elastic modulus of the sleeve teeth structure is determined to be 0.75, and the elastic modulus of the circular arc end teeth structure is 0.9. The comparison of the multi-order bending mode frequencies obtained from the simulation analysis and the modal test is as follows in the table:

[0036]

[0037] When conducting the modal test on the rotor component, the test pieces of the low-pressure turbine shaft or the sleeve teeth and circular arc end teeth connection structure used do not carry rotor blades, which can reduce the local mode of the blades and reduce the workload of correction.

[0038] Taking the equivalent support stiffness correction of the fan in the aero-engine as an example, the stiffness correction method in the aero-engine rotor component dynamics simulation model of the present application is described:

[0039] According to the vibration data of the whole engine test run, obtain the actual fan critical speed value with the main excitation source rotor mode shape as the main mode;

[0040] In the old scheme, using the rotor dynamics simulation analysis model, carry out the sensitivity analysis of the fan critical speed to its equivalent support stiffness, and according to the obtained actual fan critical speed, inversely deduce the equivalent support stiffness of the fan;

[0041] In the new scheme, carry out the static stiffness simulation analysis of the fulcrum bearing frame, compare with the old scheme to obtain the flexibility difference. The reciprocal of the stiffness is the flexibility. Based on this flexibility value, correct the equivalent support stiffness value of the fan in the aero-engine rotor component dynamics simulation model.

[0042] In a specific embodiment, according to the vibration data of the whole engine test run, the fan critical speed is obtained as 6500 r / min to 7200 r / min;

[0043] In the old scheme, carry out the sensitivity analysis of the fan critical speed to its equivalent support stiffness, and the results are as Figure 2As shown, take the lower limit of the test run result, 6500 r / min, and through comparative analysis, the equivalent support stiffness is obtained as 3.13×10 7 N / m, and the corresponding flexibility is 31.9×10 －9 m / N;

[0044] In the new scheme, the static stiffness of the load-bearing frame of the fan in the dynamic simulation model of the aero-engine rotor component is simulated and analyzed. Compared with the old scheme, its static flexibility is reduced by 0.6×10 －9 m / N. Therefore, the equivalent flexibility of the support point in the new scheme is 31.3×10 －9 m / N, and the equivalent stiffness of the fan support point in the new scheme is corrected to 3.2×10 7 N / m. By using the corrected equivalent support stiffness, the actual fan critical speed in the subsequent full-machine test run of the new scheme engine can be evaluated more accurately.

[0045] The various embodiments in the specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0046] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings. Those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.

Claims

1. A stiffness correction method in the dynamic simulation model of an aero-engine rotor component, characterized in that Including: Conduct a modal test on the rotor component to obtain the multi-order bending modal frequencies of the rotor component; Establish a dynamic simulation model of the rotor component and correct its mass to match that of the rotor component; Based on the dynamic simulation model of the rotor component, analyze the relationship between the multi-order bending modal frequencies of the rotor component and its elastic modulus; Based on the corrected elastic modulus in the simulation model with a high correlation with the bending modal frequencies of each order obtained from the modal test of the rotor component, correct the stiffness in the dynamic simulation model of the rotor component.

2. The method for correcting the stiffness in the dynamic simulation model of the aero-engine rotor component according to claim 1, characterized in that: It further includes: Carry out a full-engine test run to obtain the engine dynamic characteristic results; Adopt the simulation model with the corrected rotor stiffness, and carry out a sensitivity analysis of the critical speed to a certain support stiffness according to the dynamic characteristic characteristics; Based on the comparison between the full-engine test run results and the simulation results, obtain the experimentally verified equivalent support stiffness value, which is called the equivalent stiffness value of the old scheme; For the derived new scheme engine, analyze the static stiffness of the support bearing structure of the new scheme and the old scheme to obtain the difference between the two; Use the sum of the equivalent support stiffness value of the old scheme and the difference to obtain the equivalent support stiffness value of the derived new scheme.

3. The method for correcting the stiffness in the dynamic simulation model of the aero-engine rotor component according to claim 2, characterized in that: The unknown parameters for correcting the stiffness of the simulation model need to be controlled within 2; Due to the complexity of the rotor system, the modal test needs to be carried out step by step in stages; The rotor component has a slender shaft or a sleeve tooth and an arc end tooth connection structure.

4. The method for correcting the stiffness in the dynamic simulation model of the aero-engine rotor component according to claim 3, characterized in that: When conducting the modal test on the rotor component, the test piece used does not carry rotor blades to reduce the local modes of the rotor component.

5. The stiffness correction method in the aeroengine rotor component dynamics simulation model according to claim 4, characterized in that It further includes: Plan the corresponding full-engine test run to obtain the vibration characteristics; Based on the vibration data of the full-engine test run, obtain the critical speed of the fan; Analyze the relationship between the fan critical speed and its sensitive support stiffness to obtain its equivalent support stiffness; For the derived new scheme aero-engine, carry out a static stiffness simulation analysis of the fan support bearing structure to obtain the flexibility difference, and use this flexibility difference to correct the equivalent support stiffness value of the fan of the derived new scheme aero-engine.

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