A method for determining the bolt hole configuration of the front baffle of a turbine disk

Abstract

The present application provides a method for determining the bolt hole configuration of a turbine disk front baffle, including: constructing a turbine disk front baffle test piece including a plurality of bolt hole configurations, the turbine disk front baffle test piece is circular, and the bolt holes of the plurality of configurations are arranged symmetrically in the circumferential direction about the center of the turbine disk front baffle test piece; conducting a low-cycle fatigue comparison test on the turbine disk front baffle test piece to obtain the test cycle number of crack initiation and expansion of bolt holes of different configurations; determining the optimal bolt hole structure scheme according to the sequence and cycle number of crack initiation and expansion of the bolt holes under each configuration, wherein the optimal bolt hole structure scheme is a bolt hole configuration with a later sequence of crack initiation and expansion of the bolt holes and / or a larger number of cycles. The present application designs bolt hole structures of various shapes on the same front baffle test piece, thereby realizing one test to verify a plurality of bolt hole configurations, thereby greatly shortening the test cycle, saving test costs, and quickly screening out the optimal bolt hole structure scheme.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft engine structure testing, and in particular relates to a method for determining the configuration of bolt holes on a front baffle of a turbine disk. Background Art

[0002] The turbine disk of an aircraft engine is subjected to complex load conditions such as high centrifugal load and thermal load, and is the weakest part of the entire engine life. In particular, stress concentration parts such as the bolt holes of the front baffle of the turbine disk that are limited by bolts have high stress and become the key part that limits the service life of the turbine rotor components and even the entire engine.

[0003] like Figure 1 The figure shows a typical schematic diagram of the front baffle structure of a turbine disk. The front baffle 1 has a bolt hole 11. For the stress concentration part of the turbine rotor, the above problems are often overcome by adding a relief groove 12 and optimizing the shape of the bolt hole 11. However, since it takes a long time and high cost from design to test verification, only one structural solution can be selected for verification based on design experience, and the optimal unloading design cannot be obtained, which affects the long-life safe use of the engine. Summary of the invention

[0004] The object of the present application is to provide a method for determining a bolt hole configuration of a front baffle of a turbine disk, so as to solve or alleviate at least one problem in the background technology.

[0005] The technical solution of the present application is: a method for determining the configuration of the bolt holes of the front baffle of a turbine disk, the method comprising:

[0006] Constructing a turbine disk front baffle test piece including a plurality of bolt hole configurations, wherein the turbine disk front baffle test piece is circular, and the bolt holes of the plurality of configurations are symmetrically arranged in the circumferential direction about the center of the turbine disk front baffle test piece;

[0007] A low cycle fatigue comparison test is performed on the turbine disk front baffle test piece to obtain the test cycle numbers of crack initiation and propagation of bolt holes with different configurations;

[0008] The optimal bolt hole structure scheme is determined according to the sequence and cycle number of crack initiation and propagation of the bolt hole under each configuration, wherein the optimal bolt hole structure scheme is a bolt hole configuration with a later sequence of crack initiation and propagation of the bolt hole and / or a larger cycle number.

[0009] Furthermore, the bolt hole configuration includes a circular configuration, a rectangular rounded corner configuration, a racetrack circle configuration and an elliptical configuration.

[0010] Furthermore, the maximum outer diameters of the bolt holes of various shapes are consistent.

[0011] Furthermore, before the low cycle fatigue test is performed on the turbine disk front baffle test piece, the method further includes:

[0012] The turbine disk front baffle test piece is tested to obtain the stress distribution of bolt holes of various configurations on the turbine disk front baffle test piece along the circumferential direction.

[0013] Furthermore, the stress distribution of bolt holes of various configurations along the circumferential direction is obtained by finite element analysis.

[0014] Furthermore, when the low cycle fatigue comparison test is performed on the turbine disk front baffle test piece, the test load is the load condition during actual operation of the engine, and the load condition includes centrifugal load and temperature load.

[0015] Furthermore, when conducting a low-cycle fatigue comparison test on the turbine disk front baffle test piece, a reference cycle spectrum of "0 ~ design state speed ~ 0" is used. During the test, the crack conditions of the front baffle bolt holes are monitored, and the test cycle numbers of crack initiation and propagation of bolt holes of different configurations are recorded.

[0016] In addition, the present application also provides a turbine disk front baffle, the turbine disk front baffle having bolt holes, and the bolt hole configuration is determined by any of the above methods.

[0017] The method of the present application achieves the goal of verifying multiple structures in one test by designing bolt hole structures of various shapes on the same front baffle test piece, and conducting multi-void coupling life analysis and verification of the turbine disk front baffle test piece. It can greatly shorten the design and test cycle, save a lot of test costs such as manpower and material resources, and quickly screen out the optimal bolt hole structure solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0019] Figure 1 This is a schematic diagram of the bolt hole structure of a typical turbine disk front baffle.

[0020] Figure 2 The present invention is a flow chart of a method for determining a bolt hole configuration of a front baffle of a turbine disk.

[0021] Figure 3a to Figure 3c Schematic diagram of three typical bolt hole structures of turbine disk front baffles.

[0022] Figure 4 This is a schematic diagram of the bolt hole distribution of the turbine disk front baffle test piece in this application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0024] In order to overcome the problems of long verification cycle and high cost in the prior art, the present application proposes a method for quickly determining the bolt hole configuration of the front baffle of a turbine disk.

[0025] like Figure 2 As shown, the method proposed in this application includes the following process:

[0026] Step S01, constructing a turbine disk front baffle test piece.

[0027] At present, in the structural design of aircraft engine turbine rotor components, the most commonly used bolt hole structures are round holes, rectangular circles, elliptical holes, and runway-shaped holes (rectangular in the middle and semicircular on both sides). Figure 2 The illustrated embodiment provides three typical bolt hole structures: round hole, rectangular rounded hole and elliptical hole. The advantages and disadvantages of each bolt hole structure are as follows:

[0028] a) The advantage of a round hole is that it is easy to process, but the disadvantage is that the stress concentration phenomenon is more significant, and there is a risk of high stress around the bolt hole;

[0029] b) The advantages of rectangular holes with rounded corners and elliptical holes are that the stress concentration phenomenon is alleviated compared to circular holes. The disadvantages are that they are difficult to process and the surface integrity is difficult to ensure.

[0030] The turbine disc front baffle test piece with multiple bolt hole configurations constructed in this application is circular, and is divided into multiple sectors circumferentially with the center of the circle of the turbine disc front baffle test piece, and bolt holes of various configurations are processed at the center position of each sector, wherein bolt holes of the same configuration are arranged in sectors at symmetrical positions. As shown in FIG3 , the turbine disc front baffle test piece of the embodiment has three bolt holes of various configurations processed in the test piece, namely, circular holes, rectangular holes with rounded corners, and elliptical holes. Therefore, the turbine disc front baffle test piece is divided into 6 sectors in total, and the three bolt holes of various configurations in the 6 sectors are distributed circumferentially, and the diagonals are respectively the same bolt hole configurations. This symmetrical bolt hole configuration design can ensure the circumferential uniformity of the test piece and the imbalance of the turbine rotor system under high-speed rotation. In addition, the bolt holes of various configurations are kept consistent in their radial radius height, that is, the maximum outer diameter edge is kept consistent, thereby ensuring the uniformity of the stress distribution of the bolt holes of various configurations along the circumferential direction and eliminating the influence of structural differences at the junction position.

[0031] Step 02: Verification of low cycle fatigue comparison test of turbine disk front baffle test piece.

[0032] A low-cycle fatigue comparison test is carried out on the turbine disk front baffle test piece constructed by the above process. The test environment is to simulate the load conditions of the turbine disk front baffle structure during actual engine operation, which mainly include centrifugal load and temperature load.

[0033] During the test, the equal damage principle was adopted, and the test adopted the benchmark cycle spectrum of "0~design state speed~0". During the test, the crack situation at the bolt hole position of the front baffle was monitored, and the test cycle number of crack initiation and expansion of bolt holes of different configurations was recorded. For example, if the design state speed is 12000r / min, then during the test, a benchmark cycle spectrum is "0r / min~12000r / min~0r / min". During the test, the benchmark load spectrum is cyclically loaded, and this cycle is repeated until cracks are generated in bolt holes of different configurations. The load spectrum cycle number of crack generation is recorded, and the load spectrum cycle number when the crack expansion becomes larger or longer is recorded.

[0034] Preferably, before the low-cycle fatigue comparison test of the turbine disk front baffle, a strength analysis of the turbine disk front baffle test piece can be performed, and the strength analysis of the turbine disk front baffle test piece can be carried out by finite element method. By performing static strength analysis on the turbine disk front baffle test piece, the stress distribution law of bolt holes of different configurations along the circumferential direction is obtained, thereby providing a reference for determining the optimal structural solution and providing a simulation analysis basis for the test results.

[0035] Step S03: determine the optimal structural solution according to the test results.

[0036] The optimal bolt hole structure is determined based on the order and number of cycles of crack initiation and expansion of bolt holes of various configurations, and combined with the engine life design requirements. Generally, the optimal bolt hole structure is a bolt hole configuration with a large number of load cycles when crack initiation occurs, or a bolt hole configuration with a slow crack expansion rate (large number of cycles). Preferably, the optimal bolt hole structure is a bolt hole configuration with a large number of load cycles when crack initiation occurs and a slow crack expansion rate.

[0037] The method of the present application achieves the goal of verifying multiple structures in one test by designing bolt hole structures of various shapes on the same front baffle test piece, and conducting multi-void coupling life analysis and verification of the turbine disk front baffle test piece. It can greatly shorten the design and test cycle, save a lot of test costs such as manpower and material resources, and quickly screen out the optimal bolt hole structure solution.

[0038] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining the bolt hole configuration of a turbine disk front baffle, characterized in that: The method comprises: Constructing a turbine disk front baffle test piece including a plurality of bolt hole configurations, wherein the turbine disk front baffle test piece is circular, and the bolt holes of the plurality of configurations are symmetrically arranged in the circumferential direction about the center of the turbine disk front baffle test piece; A low cycle fatigue comparison test is performed on the turbine disk front baffle test piece to obtain the test cycle numbers of crack initiation and propagation of bolt holes with different configurations, wherein, when the low cycle fatigue comparison test is performed on the turbine disk front baffle test piece, a reference cycle spectrum of "0~design state speed~0" is used, the crack conditions of the front baffle bolt holes are monitored during the test, and the test cycle numbers of crack initiation and propagation of bolt holes with different configurations are recorded; The optimal bolt hole structure scheme is determined according to the sequence and cycle number of crack initiation and propagation of the bolt hole under each configuration, wherein the optimal bolt hole structure scheme is a bolt hole configuration with a later sequence of crack initiation and propagation of the bolt hole and / or a larger cycle number.

2. The method for determining the bolt hole configuration of the front baffle of a turbine disk according to claim 1, characterized in that: The bolt hole configurations include a circular configuration, a racetrack circle configuration, a rectangular rounded corner configuration, and an elliptical configuration.

3. The method for determining the bolt hole configuration of the front baffle of a turbine disk according to claim 2, characterized in that: The maximum outer diameter of bolt holes of various shapes is consistent.

4. The method for determining the bolt hole configuration of the front baffle of a turbine disk according to claim 3, characterized in that: Before performing a low cycle fatigue test on the turbine disk front baffle test piece, the method further includes: The turbine disk front baffle test piece is tested to obtain the stress distribution of bolt holes of various configurations on the turbine disk front baffle test piece along the circumferential direction.

5. The method for determining the bolt hole configuration of the front baffle of a turbine disk according to claim 4, characterized in that: The stress distribution along the circumferential direction of bolt holes with various configurations was obtained by finite element analysis.

6. The method for determining the bolt hole configuration of the front baffle of a turbine disk according to claim 1, characterized in that: When the low cycle fatigue comparison test is performed on the turbine disk front baffle test piece, the test load is the load condition when the engine is actually working, and the load condition includes centrifugal load and temperature load.

7. A turbine disc front baffle, characterized in that: The turbine disk front baffle has bolt holes, and the bolt hole configuration is determined by the method according to any one of claims 1 to 6.

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