A turbine blade root extension vibration fatigue test piece and a method for constructing the same

Abstract

The application provides a turbine blade root extension vibration fatigue test piece and a construction method thereof. The method comprises the following steps: obtaining a real turbine blade, wherein the real turbine blade comprises a blade body, a root extension and a tenon; cutting the blade body of the real turbine blade to form a partial blade body, and cutting the tenon of the real turbine blade to form a complete root extension and a partial tenon; the cutting positions of the blade body and the tenon of the real turbine blade are such that the bending section modulus of the root extension position is the lowest, and the first-order natural frequency of the turbine blade after cutting is the same as or similar to that of the real turbine blade; machining a fixed clamping end head; and fixing the fixed clamping end head to the tenon position after cutting, thereby forming the turbine blade root extension vibration fatigue test piece. The method provided by the application can accurately obtain the fatigue limit data of the root extension position of the turbine blade.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a turbine blade root extension vibration fatigue test piece. Background Technology

[0002] Obtaining fatigue performance data for different parts of turbine blades is fundamental to evaluating the structural strength and reliability of turbine blades and is a crucial means of ensuring the safety of turbine blades and even critical components of the entire engine. Currently, component-level vibration fatigue testing is mainly used to determine the fatigue limit of turbine blades. However, for turbine blades, the failure location during testing is primarily at the blade root; therefore, the tested fatigue performance only reflects the fatigue resistance level of the blade root. Currently, blade root fracture is gradually becoming the main failure mode for turbine blades. Simply using the blade root fatigue limit cannot accurately evaluate the dynamic strength reserve at the root; therefore, obtaining the fatigue limit at the root is of great significance.

[0003] To address the aforementioned issues, Chinese invention patent CN108267302A discloses a test piece for testing the strength of a fan blade tenon. This piece includes a tenon and an upper extension of the tenon, employing the same machining process as the blade, and exhibiting failure modes and stress components similar to those of a real fan blade. However, this test piece is a redesigned component, differing from a real blade in materials and manufacturing processes, and therefore cannot reflect the fatigue performance of a real blade at this specific location, thus presenting significant limitations. Summary of the Invention

[0004] The purpose of this application is to provide a turbine blade root extension vibration fatigue test specimen and a method for constructing the same, in order to solve or mitigate at least one of the problems in the prior art.

[0005] The technical solution of this application is: a method for constructing a turbine blade root extension vibration fatigue test specimen, the method comprising:

[0006] Obtain a real turbine blade, which includes the blade body, extension root, and tenon;

[0007] Cuttings are made on the blade of a real turbine blade to form a partial blade body, and cuttings are made on the tenon of a real turbine blade to form a complete root and a partial tenon. The cut parts of the blade body and tenon of the real turbine blade are such that the bending section modulus of the root part is the lowest and the first natural frequency of the cut turbine blade is the same as or similar to that of the real turbine blade.

[0008] Manufacturing and processing of fixed clamping ends;

[0009] The fixed clamping end is fixed to the cut tenon part to form a turbine blade root extension vibration fatigue test specimen.

[0010] Furthermore, the cut surfaces of the blade body and tenon of the actual turbine blade are parallel to the engine axis.

[0011] Furthermore, the cut portion of the tenon shown is located at the widest section of the tenon.

[0012] Furthermore, the fixed clamping end is fixed by welding to the cut tenon portion.

[0013] On the other hand, this application also provides a turbine blade root extension vibration fatigue test specimen, the turbine blade root extension vibration fatigue test specimen comprising:

[0014] A cut turbine blade having a partial blade body, a complete extension root, and a partial tenon, wherein the cut turbine blade is obtained from a real turbine blade, the blade body of the real turbine blade is formed by cutting the blade body to form a partial blade body, and the extension root of the real turbine blade is formed by cutting the tenon of the real turbine blade to form a complete extension root and a partial tenon, wherein the cut parts of the blade body and the tenon of the real turbine blade make the bending section modulus of the extension root part the lowest and the first natural frequency of the cut turbine blade is the same as or similar to that of the real turbine blade.

[0015] A fixed clamping end is fixed to the cut tenon portion.

[0016] Furthermore, the cut surfaces of the blade body and tenon of the actual turbine blade are parallel to the engine axis.

[0017] Furthermore, the cut portion of the tenon shown is located at the widest section of the tenon.

[0018] Furthermore, the fixed clamping end is fixed by welding to the cut tenon portion.

[0019] Furthermore, the fixed clamping end includes an integrally connected fixed end and a clamping end. The connecting surface of the fixed end is adapted to the cutting surface of the tenon. The width of the clamping end is greater than that of the fixed end, and there is a smooth transition between the fixed end and the clamping end.

[0020] Furthermore, the cut turbine blade also includes a rim plate located between a portion of the blade body and the complete extension root, the rim plate having a leading edge curtain and a trailing edge curtain at its front and rear ends.

[0021] The turbine blade root extension vibration fatigue test specimen and its construction method provided in this application can accurately obtain fatigue limit data of the turbine blade root extension part, and have a wider range of applicable sampling locations, high sampling positioning accuracy, and consistent positioning of multiple samplings at the same sampling location, which can better meet the actual needs of engineering. The sampling fixture has good operability when used, and achieves sampling standardization and consistency. It is of great significance for evaluating the fatigue strength of the turbine blade root extension part and improving the safety of turbine blade use. Attached Figure Description

[0022] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0023] Figure 1 This is a schematic diagram of the turbine blade root extension vibration fatigue test specimen of this application. Detailed Implementation

[0024] 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.

[0025] To address the problems in existing technologies where the structure of the integral test specimen differs from that of the actual blade, making it impossible to obtain the fatigue limit at the root, or where the structure of the component test specimen obtained through processing inevitably differs from that of the actual turbine blade, this application proposes a root vibration fatigue test specimen that can accurately obtain fatigue limit data at the root of the turbine blade.

[0026] like Figure 1 As shown, this application provides a turbine blade root extension vibration fatigue test specimen and its construction method, applicable to obtaining the vibration fatigue performance of turbine blade root structures. The method includes:

[0027] S1. Obtain real turbine blades.

[0028] like Figure 1 As shown in the left figure, the actual turbine blade 10 mainly includes the blade body 11, the extension root 17, and the tenon 18.

[0029] S2. Cut along the blade cutting surface 12 on the blade body 11 of the real turbine blade 10 so that the cut blade body 11 of the real turbine blade forms a partial blade body 11' and a blade tip 13. Cut along the tenon cutting surface 19 on the tenon 18 of the real turbine blade so that the root 17 of the real turbine blade forms a complete root and a partial tenon 18'.

[0030] Among them, the cut surface of the blade and tenon of the real turbine blade makes the bending section modulus of the root 17 the lowest, and the first natural frequency of the cut turbine blade is the same as or similar to that of the real turbine blade.

[0031] In some preferred embodiments of this application, the cut surfaces of the blade and the tenon are parallel to the engine axis, and the tenon cut surface 19 of the tenon 18 is located at the widest position of the tenon.

[0032] In addition, see also Figure 1 As shown in the left figure, the actual turbine blade 10 in this embodiment of the present application also has a rim plate 14, and the front and rear ends of the rim plate 14 have a leading edge curtain 15 and a trailing edge curtain 16, respectively.

[0033] With the above settings, the turbine blade after cutting ensures the integrity of the root 17 structure (the root 17 structure is completely consistent with the real turbine blade), and the root 17 has the lowest bending section modulus (that is, the part with the highest vibration stress of the test piece). It will break or be damaged first during the test, so as to truly reflect the vibration fatigue limit of the root 17 part of the turbine blade.

[0034] S3. Machining and manufacturing the fixed clamping end.

[0035] like Figure 1 As shown in the right figure, the fixed end 21 and the clamping end 23 are integrally formed by the fixed clamping end 20. The connecting surface 22 of the fixed end 21 is adapted to the tenon cutting surface 19 of the tenon 18. The width of the clamping end 23 is greater than that of the fixed end, which facilitates clamping. The fixed end 21 and the clamping end 23 are connected by a smooth curved surface 24.

[0036] S4. Fix the fixed clamping end 20 to the cut tenon part to form a turbine blade root extension vibration fatigue test specimen.

[0037] The connecting surface of the fixed end 21 is welded to the tenon cutting surface 19, thereby connecting the tenon 18 and the fixed clamping end 20 into a rigid body.

[0038] During the test, the clamping end 23 is clamped onto the test equipment with the smooth curved surface 23 as the boundary, forming a rigid connection with the vibration fatigue tester, thereby carrying out the vibration fatigue test.

[0039] The turbine blade root extension vibration fatigue test specimen provided in this application can accurately obtain fatigue limit data of the turbine blade root extension part, and has a wider range of applicable sampling locations, high sampling positioning accuracy, and consistent positioning of multiple samplings at the same sampling location, which can better meet the actual needs of engineering. The sampling fixture has good operability when used, and achieves sampling standardization and consistency. It is of great significance for evaluating the fatigue strength of the turbine blade root extension part and improving the safety of turbine blade use.

[0040] 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 method for constructing a turbine blade root extension vibration fatigue test specimen, characterized in that, The method includes: Obtain a real turbine blade, which includes the blade body, extension root, and tenon; Cuttings are made on the blade of a real turbine blade to form a partial blade body, and cuttings are made on the tenon of a real turbine blade to form a complete root and a partial tenon. The cut parts of the blade body and tenon of the real turbine blade are such that the bending section modulus of the root part is the lowest and the first natural frequency of the cut turbine blade is the same as or similar to that of the real turbine blade. Manufacturing and processing of fixed clamping ends; The fixed clamping end is fixed to the cut tenon part to form a turbine blade root extension vibration fatigue test specimen.

2. The method for constructing a turbine blade root extension vibration fatigue test specimen as described in claim 1, characterized in that, The cut surfaces of the blade and tenon of the actual turbine blade are parallel to the engine axis.

3. The method for constructing a turbine blade root extension vibration fatigue test specimen as described in claim 1, characterized in that, The cut portion of the tenon shown is located at the widest section of the tenon.

4. The method for constructing a turbine blade root extension vibration fatigue test specimen as described in claim 1, characterized in that, The fixed clamping end is fixed by welding to the tenon part after cutting.

5. A turbine blade root extension vibration fatigue test specimen, characterized in that, The turbine blade root extension vibration fatigue test specimen includes: A cut turbine blade having a partial blade body, a complete extension root, and a partial tenon, wherein the cut turbine blade is obtained from a real turbine blade, the blade body of the real turbine blade is formed by cutting the blade body to form a partial blade body, and the extension root of the real turbine blade is formed by cutting the tenon of the real turbine blade to form a complete extension root and a partial tenon, wherein the cut parts of the blade body and the tenon of the real turbine blade make the bending section modulus of the extension root part the lowest and the first natural frequency of the cut turbine blade is the same as or similar to that of the real turbine blade. A fixed clamping end is fixed to the cut tenon portion.

6. The turbine blade root extension vibration fatigue test specimen as described in claim 5, characterized in that, The cut surfaces of the blade and tenon of the actual turbine blade are parallel to the engine axis.

7. The turbine blade root extension vibration fatigue test specimen as described in claim 5, characterized in that, The cut portion of the tenon shown is located at the widest section of the tenon.

8. The turbine blade root extension vibration fatigue test specimen as described in claim 5, characterized in that, The fixed clamping end is fixed by welding to the tenon part after cutting.

9. The turbine blade root extension vibration fatigue test specimen as described in claim 8, characterized in that, The fixed clamping end includes an integrally connected fixed end and a clamping end. The connecting surface of the fixed end is adapted to the cutting surface of the tenon. The width of the clamping end is greater than that of the fixed end. The fixed end and the clamping end have a smooth transition.

10. The turbine blade root extension vibration fatigue test specimen as described in claim 5, characterized in that, The cut turbine blade also includes a rim plate located between a portion of the blade body and the complete extension root, the rim plate having a leading edge curtain and a trailing edge curtain at its front and rear ends.

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