Vibration stress margin evaluation method for stress concentration position of single crystal turbine blade

Abstract

The invention provides a vibration stress margin evaluation method for a stress concentration position of a single crystal turbine blade. The method comprises the following steps: S1, carrying out simulation analysis on the single crystal turbine blade; s2, simplifying the blade model, and carrying out simulation analysis of the simplified model; s3, carrying out a performance data test; and S4, carrying out a single crystal turbine blade vibration test, and measuring and evaluating the dynamic stress of the blade. The method can be applied to the high-cycle fatigue design of the turbine blade of the aero-engine, the stress concentration coefficient of a typical stress concentration part in each order of vibration mode is analyzed through a simulation and test combined method, and the mapping relation between the dynamic stress of the actual measurement position and the vibration stress of the stress concentration part is established. According to test run actually-measured dynamic stress data and test piece fatigue data with stress concentration coefficients, the problem that the dynamic stress margin of a stress concentration part is difficult to accurately evaluate is solved, and development of engine turbine blades is supported.

Description

Technical Field

[0001] The present invention relates to the field of vibration of aero-engine blades, and particularly to a method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade. Background Art

[0002] In the prior art, as a core component of an aero-engine, a single-crystal turbine blade determines the performance of the whole engine. Due to the complexity of the technology and the arduousness of the research and development work, there are generally problems such as low performance, short life, and high failure rate in Chinese aero-engines. The reason is that the fatigue performance of typical stress concentration parts of air-cooled single-crystal turbine blades has not been studied sufficiently. The single-crystal material, manufacturing process, structural characteristics, and service environment / load are not well understood. The high-cycle fatigue failure mechanism has not been clearly revealed, and the established models and methods are not accurate.

[0003] At present, a blade vibration design criterion has been preliminarily established in China, but it has not been theoretically verified and experimentally supported, and there is a lack of an evaluation criterion and optimization method for effectively reducing the excitation energy. There is a lack of the ability to evaluate the harmfulness of high-order modes that cannot be avoided during the design stage.

[0004] Although there is the ability to perform numerical simulation analysis on static stress, vibration characteristics, and vibration response, as well as the ability to measure the dynamic stress of the whole engine, due to structural feature limitations, the dynamic stress at the stress concentration position cannot be directly measured, and there is a lack of experimental data support for the dynamic stress at the stress concentration position.

[0005] Although an evaluation method for the anti-high-cycle ability has been established, the fatigue limit of typical stress concentration parts such as the air film holes of single-crystal turbine blades cannot be directly obtained, a fatigue limit acquisition method with high credibility and a structural parameter sensitivity database have not been established, and there is a lack of an anti-high-cycle fatigue evaluation method for typical stress concentration parts.

[0006] In view of this, the inventors of the present application have designed a method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade in order to overcome the above technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade in order to overcome the defect that the fatigue limit of typical stress concentration parts such as the air film holes of single-crystal turbine blades cannot be directly obtained in the prior art.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] A method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade, characterized in that the vibration stress margin evaluation method comprises the following steps:

[0010] S 1 、Conduct simulation analysis on a single-crystal turbine blade;

[0011] S 2 Simplify the blade model and conduct simulation analysis on the simplified model;

[0012] S 3 Conduct performance data tests;

[0013] S 4 Conduct single crystal turbine blade vibration tests to measure and evaluate the dynamic stress of the blade.

[0014] According to an embodiment of the present invention, the step S 1 includes:

[0015] S 11 Design and establish a turbine blade model;

[0016] S 12 Conduct numerical analysis on the turbine blade.

[0017] According to an embodiment of the present invention, the step S 12 includes:

[0018] S 121 Conduct blade aerodynamic, heat transfer, static and modal analysis to obtain the blade temperature field, static stress at each part of the blade and the relative stress distribution in each order of the blade under various working conditions;

[0019] S 122 Determine the stress mapping model of each part of the blade from the modal relative stress distribution;

[0020] S 123 Conduct blade harmonic response analysis to determine the linear elastic stress σ i at the stress concentration part.

[0021] According to an embodiment of the present invention, the stress concentration part is the film cooling hole.

[0022] According to an embodiment of the present invention, the step S 2 includes:

[0023] S 21 Conduct simplified blade model analysis to obtain the blade dynamic stress mapping model;

[0024] S 22 Conduct blade harmonic response analysis to determine the nominal stress S i when there is no stress concentration feature at the stress concentration part;

[0025] According to an embodiment of the present invention, the step S 21The analysis of the simplified blade model includes the numerical analysis of the simplified model, the relative stress distribution of the simplified model, and the dynamic stress mapping model of the simplified model.

[0026] According to an embodiment of the present invention, the step S 3 includes:

[0027] S 31 、According to the maximum stress σ 123 at the stress concentration part obtained in the step S i and the nominal stress S 22 at the stress concentration part obtained in the step S i , determine the stress concentration coefficient K ti =σ i / S i ;

[0028] S 32 、According to the stress concentration coefficient K ti , design the test piece;

[0029] S 33 、Carry out the static test to obtain the tensile strength of the blade material under the stress concentration coefficient K ti ;

[0030] S 34 、Carry out fatigue tests under different stress ratios to obtain the stress-life curve;

[0031] S 35 、From the test results of the step S 33 and the step S 34 , obtain the constant life curve under the stress concentration coefficient K ti ;

[0032] According to an embodiment of the present invention, the step S 4 includes:

[0033] S 41 、Carry out the blade vibration characteristic test on equipment such as a vibration table to obtain the natural frequency, vibration mode and modal relative stress distribution of the blade, and correct the stress mapping model obtained in the step S 22 ;

[0034] According to an embodiment of the present invention, the step S 4 also includes:

[0035] S 42 、Carry out the whole machine / core engine test to measure the dynamic stress response of the blade under various working conditions;

[0036] S 43, based on the dynamic stress at the actual measurement position of the strain gauge and the dynamic stress mapping relationship corrected by the test data, the dynamic stress (nominal stress) at the typical stress concentration parts of the single-crystal turbine blade is obtained;

[0037] S 44 , combined with the stress concentration factor obtained in the said step S 31 , the dynamic stress at the stress concentration part is obtained;

[0038] S 45 , and then according to the stress concentration factor K 35 obtained in the said step S ti , the equal-life curve under it is used to check the dynamic stress margin at the stress concentration part.

[0039] The positive and progressive effects of the present invention are as follows:

[0040] The method for evaluating the vibration stress margin at the stress concentration position of the single-crystal turbine blade of the present invention can be applied to the high-cycle fatigue design of the turbine blade of an aero-engine. By combining the methods of simulation and test, the stress concentration factors at the typical stress concentration parts in each order of vibration mode are analyzed, and the mapping relationship between the dynamic stress at the actual measurement position and the vibration stress at the stress concentration part is established. According to the measured dynamic stress data during the test run and combined with the fatigue data of the test pieces with stress concentration factors, the problem that it is difficult to accurately evaluate the dynamic stress margin at the stress concentration part is solved, which supports the development of the engine turbine blade. Description of the Drawings

[0041] The above-mentioned and other features, properties and advantages of the present invention will become more obvious through the following description in combination with the drawings and embodiments. The same reference numerals in the drawings always represent the same features, where:

[0042] Figure 1 is the flow chart of the method for evaluating the vibration stress margin at the stress concentration position of the single-crystal turbine blade of the present invention. Detailed Embodiments

[0043] To make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is made in combination with the drawings.

[0044] Now the embodiments of the present invention will be described in detail with reference to the drawings. Now the preferred embodiments of the present invention will be described in detail, and the examples are shown in the drawings. Whenever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0045] In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the description of the present invention may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of the description herein.

[0046] In addition, the present invention is to be understood not only by the actual terms used, but also by the meaning implied by each term.

[0047] Figure 1 It is a flowchart of a method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade of the present invention.

[0048] As Figure 1 shown, the present invention discloses a method for evaluating the vibration stress margin at the stress concentration position of a single-crystal turbine blade, which includes the following steps:

[0049] Step S 1 , conduct a simulation analysis of the single-crystal turbine blade, specifically refer to the block diagram content in part A of Figure 1 .

[0050] Preferably, the step S 1 includes:

[0051] Step S 11 , design and establish a turbine blade model;

[0052] Step S 12 , conduct a numerical analysis of the turbine blade.

[0053] Further preferably, the step S 12 includes:

[0054] Step S 121 , conduct aero-dynamics, heat transfer, statics and modal analysis of the blade to obtain the blade temperature field, the static stress of each part of the blade and the relative stress distribution of each order mode of the blade under various working conditions;

[0055] Step S 122 , determine the stress mapping model of each part of the blade from the modal relative stress distribution;

[0056] Step S 123 , conduct a harmonic response analysis of the blade to determine the linear elastic stress σ at the stress concentration position i .

[0057] Here, the stress concentration position is preferably the film hole or other part structures.

[0058] Step S 2 , simplify the blade model and conduct a simulation analysis of the simplified model, specifically refer to the block diagram content in part B of Figure 1 .

[0059] Preferably, the step S 2 includes:

[0060] Step S 21, conduct the analysis of the simplified blade model to obtain the dynamic stress mapping model of the blade.

[0061] Further preferably, in the step S 21 , the analysis of the simplified blade model includes the numerical analysis of the simplified model, the relative stress distribution of the simplified model, and the dynamic stress mapping model of the simplified model.

[0062] Step S 22 , conduct the harmonic response analysis of the blade to determine the nominal stress S when there is no stress concentration feature at the stress concentration site i .

[0063] Step S 3 , conduct the performance data test, specifically refer to the block diagram content in part C of Figure 1 .

[0064] Preferably, the step S 3 includes:

[0065] Step S 31 , according to the maximum stress σ at the stress concentration site obtained in the step S 123 and the nominal stress S at the stress concentration site obtained in the step S i , determine the stress concentration coefficient K at the stress concentration site 22 i ti = σ i / S i ;

[0066] Step S 32 , design the test piece according to the stress concentration coefficient K ti .

[0067] Step S 33 , conduct the static test to obtain the tensile strength of the blade material under the stress concentration coefficient K ti .

[0068] Step S 34 , conduct the fatigue test under different stress ratios to obtain the stress-life curve. 35

[0069] Step S 35 , obtain the constant life curve under the stress concentration coefficient K from the test results of the step S 33 and the step S 34 . ti

[0070]

[0071] Step S 4 , conduct the vibration test of the single crystal turbine blade to measure and evaluate the dynamic stress of the blade.

[0071] Preferably, the step S 4 includes:

[0072] Step S 41 Conduct blade vibration characteristic tests on equipment such as vibration tables to obtain the natural frequencies, vibration modes, and modal relative stress distributions of the blades, and correct the stress mapping model obtained in the above Step S 22 .

[0073] Further preferably, the above Step S 4 further includes:

[0074] Step S 42 Conduct the whole machine / core engine tests to measure the dynamic stress responses of the blades under various working conditions;

[0075] Step S 43 Obtain the dynamic stress (nominal stress) at the typical stress concentration sites of the single crystal turbine blades according to the dynamic stress at the actual measurement positions of the strain gauges and the corrected dynamic stress mapping relationship from the test data;

[0076] Step S 44 Combine with the stress concentration coefficient obtained in the above Step S 31 to obtain the dynamic stress at the stress concentration sites;

[0077] Step S 45 Then, according to the stress concentration coefficient K 35 obtained in the above Step S ti and the constant life curves, check the dynamic stress margin at the stress concentration sites.

[0078] According to the above process description, the method for evaluating the vibration stress margin at the stress concentration positions of the single crystal turbine blades of the present invention has the following innovative points:

[0079] I. Through the simulation analysis of the turbine blade model and the simplified blade model, respectively obtain the linear elastic dynamic stress and nominal stress at the stress concentration sites under each vibration mode, and then obtain the stress concentration coefficient.

[0080] II. By combining simulation and tests, establish the stress mapping relationship between the actual measurement positions of the blade dynamic stress and the stress concentration sites.

[0081] III. By analyzing the measured dynamic stress data and combining with the simulation analysis results and the fatigue test data of the test pieces with stress concentration coefficients, evaluate the dynamic stress margin at the stress concentration sites.

[0082] The method for evaluating the vibration stress margin at the stress concentration positions of the single crystal turbine blades of the present invention solves the problems of unclear vibration stress and difficult accurate evaluation at the typical stress concentration sites during the design and test run of the turbine blades through the combination of tests and numerical simulations, and supports the high cycle fatigue evaluation and design of the single crystal turbine blades.

[0083] In summary, the method for evaluating the vibration stress margin at the stress concentration position of the single crystal turbine blade of the present invention can be applied to the high-cycle fatigue design of the turbine blade of an aeroengine. By combining simulation and testing methods, the stress concentration coefficients at typical stress concentration sites under various vibration modes are analyzed, and the mapping relationship between the measured dynamic stress at the actual measurement position and the vibration stress at the stress concentration site is established. Based on the measured dynamic stress data during the test run and combined with the fatigue data of the test piece with the stress concentration coefficient, the problem of difficult accurate evaluation of the dynamic stress margin at the stress concentration site is solved, supporting the development of the engine turbine blade.

[0084] For those skilled in the art, the above disclosure of the invention is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0085] At the same time, specific terms are used in this application to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0086] Similarly, it should be noted that, in order to simplify the description of this application disclosure and thus help the understanding of one or more embodiments of the invention, in the previous description of the embodiments of this application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than those mentioned in the claims. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0087] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade, Characterized in that, The method for evaluating the vibration stress margin includes the following steps: S 1 , conduct simulation analysis of single crystal turbine blades; S 2 , simplify the blade model and conduct simulation analysis on the simplified model; S 3 and conduct performance data tests; S 4 Conduct vibration tests on single crystal turbine blades and measure and evaluate the dynamic stress of the blades.

2. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 1, Characterized in that, The said step S 1 includes: S 11 Design and establish a turbine blade model; S 12 Perform numerical analysis on the turbine blade.

3. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 2, Characterized in that, The said step S 12 includes: S 121 Conduct aerodynamic, heat transfer, statics and modal analyses of the blade to obtain the blade temperature field, static stress at each part of the blade and the relative stress distribution in each order of blade modes under various working conditions; S 122 Determine the stress mapping model of each part of the blade from the modal relative stress distribution; S 123 Perform blade harmonic response analysis to determine the linear elastic stress σ at the stress concentration location i .

4. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 3, Characterized in that, The stress concentration part is a film hole.

5. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 3, Characterized in that, The said step S 2 includes: S 21 , conduct simplified blade model analysis to obtain the blade dynamic stress mapping model; S 22 Perform a blade harmonic response analysis to determine the nominal stress S when there is no stress concentration feature at the stress concentration site i .

6. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 5, Characterized in that, The said step S 21 The simplified blade model analysis in it includes simplified model numerical analysis, simplified model relative stress distribution, and simplified model dynamic stress mapping model.

7. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 5, Characterized in that, The said step S 3 includes: S 31 Based on the maximum stress σ 123 at the stress concentration location obtained in the said step S i and the nominal stress S 22 at the stress concentration location obtained in the said step S i , determine the stress concentration factor K ti = σ i / S i ; S 32 、Design a test piece according to the stress concentration factor K ti . S 33 、Conduct a static test to obtain the tensile strength of the blade material under the stress concentration coefficient K ti ; S 34 Conduct fatigue tests under different stress ratios to obtain stress-life curves; S 35 and the stress concentration factor K 33 is obtained from the test results of the step S 34 and the step S ti to obtain an isochronous curve under 8. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 7, Characterized in that, The said step S 4 includes: S 41 Perform blade vibration characteristic tests on equipment such as a vibration table to obtain the natural frequency, vibration mode, and modal relative stress distribution of the blade, and correct the stress mapping model obtained in step S 22 above.

9. The method for evaluating the vibration stress margin at the stress concentration position of a single crystal turbine blade according to claim 8, Characterized in that, The said step S 4 further includes: S 42 Conduct the whole machine / core engine test to measure the dynamic stress response of the blade under various working conditions; S 43 、Based on the measured dynamic stress of the strain gauge at the actual position and the dynamic stress mapping relationship corrected by the test data, the dynamic stress (nominal stress) at the typical stress concentration part of the single crystal turbine blade is obtained; S 44 and in combination with the stress concentration factor obtained in the said step S 31 obtain the dynamic stress at the stress concentration location; S 45 and then, according to the step S 35 to obtain the stress concentration factor K ti for the constant life curve under, check the dynamic stress margin of the stress concentration part.

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