A small-size turbine blade strength simulation test piece design method

Abstract

The application belongs to the field of aero-engine test, and particularly relates to a small-size turbine blade strength simulation test piece design method, steps S1: the structure and strength of a turbine blade are analyzed through software, and relatively flat parts and parts with more serious life damage of the turbine blade are selected as sampling positions; step S2: a small-size test piece is designed according to the structure characteristics and size of the sampling positions, the main bearing direction of the turbine blade and the crystal orientation, and a standard test piece structure form; step S3: the strength of the test piece in a simulation test environment is analyzed, and the structure and size of the small-size test piece are corrected; step S4: the small-size test piece is processed; the application proposes a small-size strength simulation test piece influencing factor analysis method, identifies small-size strength simulation test piece influencing factors, verifies the effectiveness of the method, and improves the engineering applicability of the small-size strength simulation test piece.

Description

Technical Field

[0001] This application belongs to the field of aero-engine testing, and specifically relates to a design method for a small-sized turbine blade strength simulation test piece. Background Technology

[0002] Material properties are fundamental to the structural strength design of aero-engines and are a crucial input for ensuring the accuracy of strength design. It is well known that the performance of actual turbine blade components differs from that of standard parts, especially for turbine blades, which have complex structures and utilize advanced high-temperature alloys such as directional and single-crystal alloys. Therefore, obtaining specimens from actual turbine blades for mechanical property testing is essential to accurately reflect the blade's mechanical properties, surface finish, crystal orientation, thin-wall effects, and other actual conditions, obtaining reliable test data to support engine strength design and life prediction. Due to the highly complex structure of turbine blades, which are often hollow, curved, twisted, and contain special structures such as film cooling holes, diaphragms, and spoiler columns, small-sized non-standard parts are frequently used for sampling. Therefore, overcoming the design technology of small-sized simulated test specimens, meeting the requirements for processing and testing specifications, and ensuring the validity and accuracy of the obtained data are key technologies for sampling actual blades and evaluating the mechanical properties of actual components.

[0003] The existing technical solutions have the following drawbacks:

[0004] 1) Existing technical solutions do not take into account the structure and crystal orientation characteristics of turbine blades, and the selected test specimen schemes have a low degree of matching with the characteristics of blades and the requirements of simulation tests;

[0005] 2) Existing technical solutions do not consider the impact of turbine blade processing technology, resulting in poor processing accuracy and quality, which affects the conduct of experiments and the dispersion of experimental results;

[0006] 3) Due to the combined influence of multiple factors such as the structural dimensions of the test specimen, the process plan, and the surface condition, the validity of the test results in the current technical solutions is relatively poor. Summary of the Invention

[0007] To address the aforementioned problems, this application provides a method for designing a small-sized turbine blade strength simulation test specimen, comprising:

[0008] Step S1: Analyze the structure and strength of the turbine blades using software, and select relatively flat parts and parts with more severe life damage as sampling locations.

[0009] Step S2: Design small-sized test specimens based on the structural characteristics and dimensions of the sampling location, the main load-bearing direction and crystal orientation of the turbine blades, and the structural form of standard test specimens;

[0010] Step S3: Conduct strength analysis on the test specimen under simulated test conditions, and modify the structure and dimensions of the small-sized test specimen;

[0011] Step S4: Process the small-sized test piece.

[0012] Preferably, the processing of small-sized test pieces includes:

[0013] The selection of the positioning method and the selection of the processing technology for the test specimen;

[0014] The testing specimen processing and positioning methods include: positioning on the cutting plane and positioning on the plane where the testing part is located;

[0015] The processing techniques include: slow wire EDM, milling, or fast wire EDM followed by grinding.

[0016] Preferably, the method for selecting the processing technology includes: machining small-sized test pieces with consistent original materials and test piece form by slow wire EDM, milling, or fast wire EDM followed by grinding; conducting tensile tests and endurance tests on the small-sized test pieces with different processing technologies; and selecting the processing technology whose test results meet expectations.

[0017] Preferably, the structural forms of small-sized test specimens include: short I-beam type, long I-beam type, and perforated type.

[0018] Preferably, the software used to analyze the structure and strength of turbine blades includes: analyzing the structure of turbine blades using UG software, and analyzing the strength of turbine blades using ANSYS software.

[0019] Preferably, after designing the small-sized test specimen in step S2, multiple small-sized test specimens under different influencing factors are designed, and comparative tests are carried out on multiple small-sized test specimens to identify the magnitude of the influencing factors that cause different effects on the small-sized test specimens, and the small-sized test specimens are modified based on the magnitude of the influencing factors.

[0020] Preferably, the influencing factors include: size, manufacturing process, and the presence or absence of a coating.

[0021] Preferably, the effects include: size effect, thin-wall effect, and high-temperature oxidation.

[0022] The advantages of this application include:

[0023] 1) Propose a complete small-size strength simulation test specimen scheme and its applicable scope, providing a reference for the design of small-size test specimens and the formulation of test schemes, and better meeting the actual needs of engineering;

[0024] 2) Propose a method for selecting processing schemes for small-sized strength simulation test specimens, and propose the optimal processing technology scheme;

[0025] 3) Propose a systematic method for analyzing the influencing factors of small-sized strength simulation test specimens, identify the influencing factors of small-sized strength simulation test specimens, verify the effectiveness of the method, and improve the engineering applicability of small-sized strength simulation test specimens. Attached Figure Description

[0026] Figure 1 This is a flowchart of the design method for a small-sized turbine blade strength simulation test specimen;

[0027] Figure 2 This is a schematic diagram of a short I-beam design for small-sized test specimens;

[0028] Figure 3 This is a schematic diagram of a long I-beam design for small-sized test specimens;

[0029] Figure 4 This is a schematic diagram of a drilling scheme for small-sized test pieces. Detailed Implementation

[0030] 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 inventive 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.

[0031] The technical solution of the present invention is as follows Figure 1 As shown, a method for designing small-sized strength simulation test specimens includes the following steps:

[0032] Step 1, Input

[0033] Obtain the three-dimensional geometric model of the turbine blades to be sampled, and obtain the calculation state, material property data, aerodynamic data and temperature data of the turbine blades used for strength analysis;

[0034] Step 2: Turbine Blade Structure and Strength Analysis

[0035] Based on step 1, UG software was used to conduct turbine blade structural analysis. According to the structural analysis results, locations meeting the sampling requirements were selected. ANSYS software was used to conduct turbine blade strength analysis. Based on the strength analysis results, key areas of interest were selected. Combining the results of the turbine blade structural and strength analyses, relatively smooth areas and areas with severe lifespan damage were selected as sampling locations to provide a reference for subsequent small-scale strength simulation test specimens.

[0036] Step 3, Specimen Design

[0037] Based on the analysis results of step 2, and according to the characteristics and size of the sampling location, combined with the main load-bearing direction and crystal orientation scheme of the turbine blade, test specimens were designed. Referring to the structural forms of standard parts, the small-size strength simulation test specimen schemes were mainly divided into three types: short I-beam type, long I-beam type, and perforated type. Figure 2 As shown.

[0038] Step 4: Strength analysis of test specimens

[0039] Based on the test specimen designed in step 3, the turbine blade strength analysis was carried out using ANSYS software. First, a linear elastic analysis of the test specimen under a simulated test environment was conducted to study the stress distribution characteristics of the test specimen, analyze the rationality of the structural dimensions and test load of the test specimen, and provide a reference for the determination of subsequent test parameters. On the basis of the above work, considering the small size of the test section of the small-sized strength simulation test specimen, an elastoplastic analysis of the test specimen under a simulated test environment was carried out to study whether the stress concentration at the chamfer affects the effective range of the test section, and further analyze the rationality of the test specimen size design.

[0040] Step 5: Analysis of the applicable scope of the test specimen

[0041] Based on the analysis results in step 4, and taking into account the structural characteristics of the small-size strength simulation test specimen schemes, and referring to the standard test specimen schemes, the advantages, disadvantages, and applicable scope of each small-size strength simulation test specimen scheme are clarified.

[0042] Step 6: Analysis of Factors Affecting the Test Specimens

[0043] Small-sized strength simulation test specimens are non-standard specimens, especially those cut from real blades, which introduces various influencing factors that affect the test results, such as size effect, thin-wall effect, fabrication process, specimen form, and high-temperature oxidation. Based on these issues, for step 3, we designed test specimens of different sizes, fabrication processes, coatings, and uncoated specimens, conducted comparative experiments, and identified the influencing factors of small-sized strength simulation test specimens.

[0044] Step 7: Development of the test piece processing plan

[0045] 1) Selection of machining positioning method: The selection of machining positioning surface directly affects the standardization and accuracy of machining. Due to the irregular shape of the sampled specimen, it is difficult to determine the machining positioning surface. Two positioning methods are adopted: positioning on the cutting plane (fixture positioning surface) and positioning on the plane where the test part is located. Through comparative analysis of machining process feasibility, machining quality and test results, the positioning method is determined to ensure the standardization and accuracy of the sampled test piece machining.

[0046] 2) Selection of processing technology

[0047] Different processing techniques have unpredictable effects on the surface condition, machining accuracy, and inherent properties of test specimens. For example, electrical discharge machining (EDM) and wire EDM, which use low-voltage, high-current, and instantaneous high-temperature melting of metal for cutting, produce instantaneous high-temperature cooling on the cut surface, leaving a thin oxide film. High-speed milling increases surface stress; while grinding achieves better surface quality, it also increases surface stress. The impact of processing techniques on test specimens will be verified using comparative experiments. Under the premise of consistent raw materials, test specimen types, and test conditions, different processing methods will be used to compare and analyze the processing quality and mechanical properties of test specimens. The raw material is a round bar blank used for processing standard round bar specimens; the test specimen type is a sampling I-shaped specimen; the test items are tensile and creep tests; and the processing techniques include wire EDM, milling, and wire EDM followed by grinding. By comparing the processing quality and test results, the optimal processing technique can be selected to improve the accuracy of experimental data.

[0048] Step 8: Feasibility analysis of the test piece process

[0049] Based on step 7, a test piece processing plan is developed. The feasibility of the processing plan and process is evaluated by simulating the processing of the test piece, and whether it meets the processing accuracy and quality requirements. According to the processing results, slow wire EDM is the optimal processing technology.

[0050] Step 9: Feasibility Analysis of the Experiment

[0051] Based on the test specimens processed in step 8, simulation tests were conducted to evaluate the rationality and feasibility of the design and processing scheme of the small-sized strength simulation test specimens.

[0052] 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 designing a small-sized turbine blade strength simulation test specimen, characterized in that, include: Step S1: Analyze the structure and strength of the turbine blades using software, and select relatively flat parts and parts with severe life damage as sampling locations. Step S2: Design small-sized test specimens based on the structural characteristics and dimensions of the sampling location, the main load-bearing direction and crystal orientation of the turbine blades, and the structural form of standard test specimens; Step S3: Conduct strength analysis on the test specimen under simulated test conditions, and correct the structure and dimensions of the small-sized test specimen; Step S4: Process the small-sized test piece; After designing the small-sized test specimen in step S2, several small-sized test specimens under different influencing factors are designed, and comparative tests are carried out on the multiple small-sized test specimens to identify the magnitude of the influencing factors that cause different effects on the small-sized test specimens, and the small-sized test specimens are modified based on the magnitude of the influencing factors. Influencing factors include: size, manufacturing process, and the presence or absence of a coating; The effects include: size effect, thin-wall effect, and high-temperature oxidation.

2. The design method for small-sized turbine blade strength simulation test specimens as described in claim 1, characterized in that, Processing small-sized test pieces includes: The selection of the positioning method and the selection of the processing technology for the test specimen; The testing specimen processing and positioning methods include: positioning on the cutting plane and positioning on the plane where the testing part is located; The processing techniques include: slow wire EDM, milling, or fast wire EDM followed by grinding.

3. The design method for small-sized turbine blade strength simulation test specimens as described in claim 2, characterized in that, The methods for selecting the processing technology include: machining small-sized test pieces with consistent original materials and test piece form by slow wire EDM, milling, or fast wire EDM followed by grinding; conducting tensile tests and endurance tests on the small-sized test pieces with different processing technologies; and selecting the processing technology whose test results meet expectations.

4. The design method for small-sized turbine blade strength simulation test specimens as described in claim 1, characterized in that, The structural forms of small-sized test specimens include: short I-beam type, long I-beam type, and perforated type.

5. The design method for small-sized turbine blade strength simulation test specimens as described in claim 1, characterized in that, Software used to analyze the structure and strength of turbine blades includes: UG software for analyzing the structure of turbine blades, and ANSYS software for analyzing the strength of turbine blades.

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