Method for determining strength test load of intermediate gearbox of large-bypass-ratio multi-path load

Abstract

The application provides a method for determining the strength test load of a large-bypass-ratio multi-path load intermediate gearbox, comprising: screening the maximum working condition of each path load of the intermediate gearbox, carrying out strength analysis of the intermediate gearbox to obtain stress distribution of the intermediate gearbox; determining the test position of the intermediate gearbox according to the stress distribution result of the intermediate gearbox and different stress forms of the intermediate gearbox; integrating the test working condition according to the selected test position; obtaining the stress condition of each path load at the test position through single influence analysis of each path load on the test position; according to the influence analysis result of each path load, superimposing a certain path load on another path load, and ignoring one or more path loads with less influence on the test position, thereby obtaining the test load, carrying out stress analysis of the intermediate gearbox under the test load, comparing the stress distribution of the above strength analysis result, if the requirement is met, the strength test load of the intermediate gearbox is obtained, if the requirement is not met, the test load is determined again.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-bypass-ratio aero-engine, and particularly relates to a method for determining a strength test load of a high-bypass-ratio multi-path load intermediate gearbox. BACKGROUND

[0002] The intermediate gearbox is the most important load-bearing frame in the load-bearing system of an aero-engine, and is usually composed of a plurality of gearbox layers connected by a support plate to form a spoke frame. Compared with a small-bypass-ratio engine, the high-bypass-ratio intermediate gearbox not only bears the entire axial force and part of the transverse force of the core engine stator, but also has more bearing seats installed inside to support the engine rotor. In addition, the front mounting edge of the splitter ring is connected to the structure of the booster stator. The high-bypass-ratio intermediate gearbox bears the entire load of the booster stator, and the mounting edge of the outer ring of the intermediate gearbox serves to connect and bear the load of the entire fan stator structure. The internal load of the above-mentioned engine is transmitted to the aircraft through the hanger points mounted on the intermediate gearbox to provide thrust for the aircraft.

[0003] According to the design requirements of long service life and high reliability of the high-bypass-ratio engine, a strength test of the intermediate gearbox component needs to be carried out to verify whether it meets the engineering application requirements. However, the high-bypass-ratio intermediate gearbox has multiple levels, i.e. more load paths, and it is more difficult to test and load. Therefore, under the existing test conditions, how to determine the test load of the intermediate gearbox so as to meet the test examination requirements of the high-bypass-ratio intermediate gearbox is an urgent problem to be solved. SUMMARY

[0004] The purpose of the present application is to provide a method for determining the strength test load of a high-bypass-ratio multi-path load intermediate gearbox to solve or alleviate at least one problem in the background art.

[0005] The technical solution of the present application is: a method for determining the strength test load of a high-bypass-ratio multi-path load intermediate gearbox, comprising:

[0006] screening the maximum working conditions of each load path of the intermediate gearbox, and carrying out strength analysis of the intermediate gearbox to obtain the stress distribution of the intermediate gearbox;

[0007] determining the examination positions of the intermediate gearbox according to the stress distribution results of the intermediate gearbox and different stress forms of the intermediate gearbox;

[0008] integrating the test examination working conditions according to the selected examination positions;

[0009] obtaining the stress conditions of each load path at the examination positions through single influence analysis of each load path on the examination positions;

[0010] According to the influence analysis results of each road load, a road load is superimposed on another road load, while ignoring one or more road loads which have less influence on the test site, so as to obtain a test load, carry out stress analysis of the intermediate gearbox under the test load, and compare the stress analysis results with the strength analysis results of the intermediate gearbox, so as to verify whether the stress distribution under the test load meets the requirements, if yes, the intermediate gearbox strength test load is obtained, if not, the test load is re-determined until the test load design requirements are met.

[0011] Further, the stress distribution of the intermediate gearbox is obtained by carrying out strength analysis of the intermediate gearbox through the finite element method.

[0012] Further, different stress forms of the intermediate gearbox are obtained by combining a road load maximum working condition and other road load working conditions matching the road load maximum working condition.

[0013] Further, when the single influence analysis of the test site is carried out to obtain the stress of each road load at the test site, the stress size and direction of the test site are included.

[0014] Further, the method further comprises: when the stress distribution under the test load meets the requirements, carrying out material and temperature correction of the intermediate gearbox, so as to obtain the final intermediate gearbox static strength test load.

[0015] Further, when the temperature is corrected, the temperature of the test site under each test working condition is determined to determine the temperature which needs to be corrected.

[0016] The large-bypass-ratio multi-path-load intermediate gearbox strength test load design method provided by the application can achieve the purpose of intermediate gearbox static strength test, and further ensure the long life and high reliability design requirements of the intermediate gearbox. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions provided by the application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the application.

[0018] Figure 1 The flowchart of the intermediate gearbox strength test load determination method of the application is shown.

[0019] Figure 2 The force diagram of the intermediate gearbox of an embodiment of the application is shown. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the application more clear, the technical solutions in the embodiments of the application will be described in more detail below with reference to the drawings in the embodiments of the application.

[0021] The traditional intermediate casing test load determination method can realize the test load design of the same annular casing front and rear mounting edge, but due to the characteristics of the multi-level and multi-path load of the large-bypass-ratio intermediate casing, the traditional intermediate casing test load determination method cannot be applied to the strength test of the large-bypass-ratio intermediate casing.

[0022] Therefore, in view of the characteristics of the multi-level and multi-path load of the large-bypass-ratio intermediate casing, the influence of each path load on the intermediate casing examination site is provided, and the processing mode of each path load is formulated according to each load transmission path, and finally a set of implementable intermediate casing test load is obtained on the basis of meeting the test examination requirements of the large-bypass-ratio intermediate casing.

[0023] As shown in Figure 1 The intermediate casing strength test load determination method provided by the present application for the large-bypass-ratio multi-path load comprises the following steps:

[0024] S1, intermediate casing strength analysis

[0025] According to the use environment and usage of the intermediate casing, the maximum working condition of each path load is preliminarily screened, the intermediate casing strength analysis is carried out, and the stress distribution of the intermediate casing is obtained.

[0026] Among them, the stress distribution of the intermediate casing obtained by carrying out the strength analysis of the intermediate casing can be obtained by using the finite element method.

[0027] For example Figure 2 As shown in the force schematic diagram of the large-bypass-ratio intermediate casing in an embodiment of the present application, in the intermediate casing, it mainly bears 8 path loads of fan casing load A, reverse thrust load B, booster stage casing load C / D, 1-3 fulcrum load and hanger point load. According to the use environment and usage, the maximum working condition of each path load can be screened.

[0028] S2, determine the examination site of the intermediate casing

[0029] According to the stress distribution result of the intermediate casing strength analysis, different examination sites are determined according to different stress forms of the intermediate casing, and the examination sites are used as the research object of the test examination.

[0030] The different stress forms of the intermediate casing include: the maximum working condition of the fan casing load A and the other 7 path loads matched with it constitute the first stress form; the maximum working condition of the reverse thrust load B and the other 7 path loads matched with it constitute the second stress form, and other stress forms are not described. Through the 8 different stress forms, the examination site can generally be obtained at 8 places. But under normal circumstances, although the stress forms are different, the examination sites sometimes will be superimposed or the same, that is, the examination sites determined under the 8 stress forms are only 3-4 places.

[0031] S3, determining the test condition

[0032] According to the test site determined in step 2, the test condition is integrated.

[0033] Through the integration of the test condition, the test load range can be greatly reduced.

[0034] S4, analysis of the influence of each load

[0035] Through the single influence analysis of each load on the test site, the stress of each load on the test site can be obtained, including the stress size and direction of the test site, and the stress of each load on the test site can be clearly judged. It is additive or subtractive relationship.

[0036] Through the analysis of the transmission path of each load with the test site as the research object, the loads of similar transmission paths can be combined.

[0037] S5, test load design

[0038] According to the influence analysis results of each load, the load of a certain road is added to another load, and the load of one or more roads with less influence on the test site is ignored, so as to obtain the test load, including the test load size and direction. After the intermediate nacelle stress analysis under the test load is carried out, it is compared with the intermediate nacelle strength analysis results in step S1 to verify whether the stress distribution under the test load meets the requirements. If it meets the requirements, material and temperature correction can be carried out, if it does not meet the requirements, the test load is re-determined until the test load design requirements are met.

[0039] For example, in an embodiment of the present application, the fan nacelle load A bears three-way load and three-way bending moment, and the reverse thrust load B bears only axial load. By applying the reverse thrust load B at the installation edge of the fan nacelle load A, the number of loads is simplified. At the same time, since the booster stage nacelle load C / D and the two fulcrum loads have less influence on the test site, the booster stage nacelle load C / D and the two fulcrum loads are ignored.

[0040] S6, material and temperature correction

[0041] The above test process is carried out at room temperature, while the real use environment has higher temperature than room temperature, so temperature correction is needed, and the temperature is determined by the test site temperature under each test condition. In order to consider the material performance difference of the test piece, material correction is needed.

[0042] The correction process of material and temperature can refer to the corresponding literature, which will not be repeated here.

[0043] S7, test load

[0044] After correction of material and temperature, the final intermediate gearbox static strength test load is obtained.

[0045] The method for designing the high-bypass-ratio multi-path load intermediate gearbox strength test load provided in the application can achieve the purpose of intermediate gearbox static strength test, thereby ensuring the long service life and high reliability design requirements of the intermediate gearbox.

[0046] The above merely provides a specific implementation of the application, but the protection scope of the application is not limited thereto, any changes or replacements that can be easily thought of by those skilled in the art within the technical range disclosed in the application shall be encompassed in the protection scope of the application. Therefore, the protection scope of the application shall be subject to the protection scope of the claims.

Claims

1. A method for determining test loads for high-bypass-ratio multi-path- loaded intermediate gearbox strength testing, the method comprising: determining a first test load for a first intermediate gearbox strength test; determining a second test load for a second intermediate gearbox strength test; and determining a third test load for a third intermediate gearbox strength test. The method comprises: Screening the maximum working condition of each load of the intermediate case, and carrying out strength analysis of the intermediate case to obtain stress distribution of the intermediate case; According to the stress distribution result of the intermediate case and different stress forms of the intermediate case, determining the checking position of the intermediate case; According to the selected checking position, integrating the test checking working condition; Through single influence analysis of each load on the checking position, obtaining stress of each load on the checking position; According to the influence analysis result of each load, superimposing a certain load on another load, while ignoring one or more loads with less influence on the checking position, so as to obtain the test load, carrying out stress analysis of the intermediate case under the test load, and comparing with the strength analysis result of the intermediate case to verify whether the stress distribution under the test load meets the requirements, if it meets the requirements, the intermediate case strength test load is obtained, if it does not meet the requirements, the test load is re-determined until the test load design requirements are met.

2. The method of claim 1, wherein the method further comprises: The stress distribution of the intermediate case obtained by carrying out the strength analysis is carried out by the finite element method.

3. The method of claim 1, wherein the method further comprises: Different stress forms of the intermediate case are obtained by combining the maximum working condition of a certain load and matching the maximum working condition of other loads.

4. The method of claim 1, wherein the method further comprises: The single influence analysis of the checking position obtains the stress of each load on the checking position, including the stress size and direction of the checking position.

5. The method of claim 1, wherein, It also includes: When the stress distribution under the test load meets the requirements, the material and temperature of the intermediate case are corrected to obtain the final intermediate case static strength test load.

6. The method for determining the intermediate casing strength test load for high bypass ratio multipath loads as described in claim 4, characterized in that, When the temperature is corrected, the temperature of the checking position under each checking working condition is determined to correct the temperature.

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