A method for designing a multilayer engine case containment

Abstract

The application belongs to the technical field of aero-engine multilayer casing containment design, and particularly relates to a multilayer casing containment design method for an aero-engine, which comprises the following steps: extracting the wall thickness and material performance of the multilayer casing; performing equivalent conversion on the wall thickness of the multilayer casing; wherein h is the equivalent wall thickness of the multilayer casing; i is the number of layers of the multilayer casing; h i is the thickness of the i-th layer of casing; performing equivalent conversion on the material performance of the multilayer casing; wherein sigma is the equivalent material performance of the multilayer casing; alpha i is the material performance of the i-th layer of casing; calculating the containment capacity of the multilayer casing based on the equivalent wall thickness h of the multilayer casing and the equivalent material performance sigma of the multilayer casing; evaluating whether the containment capacity of the multilayer casing meets the containment design requirement; if not, adjusting the design of the multilayer casing until the containment capacity of the multilayer casing meets the containment design requirement.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft engine multi-layer casing containment design, and specifically relates to an aircraft engine multi-layer casing containment design method. Background Art

[0002] When an aero-engine non-containment accident occurs, high-speed and high-energy fragments penetrate the casing and fly out, damaging the aircraft cabin, fuel tank, hydraulic pipelines, electrical control circuits, etc., causing cabin depressurization, fuel tank leakage and fire, aircraft control failure, etc., seriously endangering the flight safety of the aircraft. The containment design of the aero-engine casing is an important part of aero-engine development.

[0003] The design of aircraft engine casing containment involves the calculation of the casing containment capacity. Currently, empirical formulas are mostly used for calculation. After testing and use verification, it has high accuracy for single-layer casings. However, when it is applied to multi-layer casings, the solution of calculating the containment capacity of each layer of casing separately and then superimposing them is adopted. The containment capacity of the obtained multi-layer casing is greatly different from the actual one, and it is impossible to analyze the impact of the material difference of each layer of casing on the containment capacity. Based on this design of multi-layer casing containment, the resulting casing often has thicker walls, which increases the mass of the aircraft engine as a whole and is not conducive to improving the thrust-to-weight ratio of the aircraft engine.

[0004] This application is proposed in view of the above-mentioned technical defects.

[0005] It should be noted that the disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0006] The purpose of this application is to provide a method for designing the containment of a multi-layer casing of an aircraft engine to overcome or alleviate at least one of the known technical defects.

[0007] The technical solution of this application is:

[0008] A method for designing the containment of a multi-layer casing of an aircraft engine, comprising:

[0009] Extract multi-layer casing wall thickness and material properties;

[0010] Equivalent conversion of multi-layer casing wall thickness: Where h is the equivalent wall thickness of the multi-layer casing; i is the number of layers of the multi-layer casing; h i is the thickness of the i-th layer casing;

[0011] Equivalent conversion of multi-layer casing material performance: Where σ is the equivalent material performance of the multi-layer casing; α i is the material property of the i-th layer casing;

[0012] The containment capacity of the multi-layer casing is calculated based on the equivalent wall thickness h and the equivalent material performance σ of the multi-layer casing;

[0013] Evaluate whether the containment capacity of the multi-layer casing meets the containment design requirements. If not, adjust the design of the multi-layer casing until the containment capacity of the multi-layer casing meets the containment design requirements.

[0014] According to at least one embodiment of the present application, in the above-mentioned multi-layer casing containment design method, the material properties include material shear strength.

[0015] According to at least one embodiment of the present application, in the aforementioned multi-layer casing containment design method, when the containment capacity of the multi-layer casing does not meet the containment design requirements, adjusting the design of the multi-layer casing includes:

[0016] Increase the wall thickness of the receiver;

[0017] Replace the material of the receiver;

[0018] Add reinforcement ribs to the receiver;

[0019] A containment ring is added to the receiver.

[0020] This application has at least the following beneficial technical effects:

[0021] A method for designing the containment of a multi-layer casing of an aircraft engine is provided. When calculating the containment capacity of the multi-layer casing, the wall thickness and material properties of the multi-layer casing are converted proportionally, and the multi-layer casing is calculated as equivalent to a single-layer casing. The method has been verified to have high accuracy through experiments, and is convenient for analyzing the influence of the material difference of each layer of the casing on the containment capacity, and is convenient for designing and improving the multi-layer casing. Based on this, the containment design of the multi-layer casing can avoid the casing wall thickness being too thick, thereby reducing the weight of the aircraft engine as a whole and facilitating the improvement of the thrust-to-weight ratio of the aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the aircraft engine multi-layer casing containment design method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0024] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0025] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0026] The following is combined with Figure 1 This application is described in further detail.

[0027] A method for designing the containment of a multi-layer casing of an aircraft engine, comprising:

[0028] Extract the wall thickness and material properties of multi-layer casings, which can be extracted from design drawings and related documents;

[0029] Equivalent conversion of multi-layer casing wall thickness: Where h is the equivalent wall thickness of the multi-layer casing; i is the number of layers of the multi-layer casing; h i is the thickness of the i-th layer casing;

[0030] Equivalent conversion of multi-layer casing material performance: Where σ is the equivalent material performance of the multi-layer casing; α i is the material property of the i-th layer casing, where the material property refers to the shear strength of the material;

[0031] The containment capacity of the multi-layer casing is calculated based on the equivalent wall thickness h and the equivalent material performance σ of the multi-layer casing. Other relevant parameters involved in the calculation of the containment capacity of the multi-layer casing can be extracted from the design drawings and related documents and calculated using conventional formulas and methods.

[0032] Evaluate whether the containment capacity of the multi-layer casing meets the containment design requirements. The specific containment design requirements can be determined through the top-level report or by referring to relevant standards. When evaluating the containment capacity of the multi-layer casing, other relevant parameters involved can be extracted from the design drawings and related documents and calculated using conventional formulas and methods.

[0033] When the containment capacity of the multi-layer receiver does not meet the containment design requirements, the design of the multi-layer receiver is adjusted, including increasing the wall thickness of the receiver, replacing the material of the receiver, adding reinforcing ribs to the receiver, adding containment rings to the receiver, etc., until the containment capacity of the multi-layer receiver meets the containment design requirements.

[0034] Based on the equivalent wall thickness h and the equivalent material performance σ of the multi-layer casing, the containment capacity of the multi-layer casing is calculated using the following formula:

[0035] A=Lh 2 τ D (0.5K+n);

[0036] in,

[0037] A is the potential energy of multilayer casing failure, N·m, which represents the containment capacity of the multilayer casing;

[0038] L is the perimeter of the blade outer edge section that collides with the multi-layer casing, m;

[0039] τ D is the dynamic strength shear limit of the multilayer casing material, MPa. When data is missing, τ can be taken D =1.3τ b , τ b It is the static shear strength limit of the multi-layer casing material. Its calculation can refer to

[0040] K is the empirical coefficient of bending deformation. When there is a lack of specialized experience, K = 2.5 is generally taken;

[0041] n is the empirical coefficient of shear deformation. When there is a lack of specialized experience, N=0.7 is generally taken.

[0042] When evaluating the containment capacity of a multi-layer casing, the following formula can be used to calculate the kinetic energy of the broken blade part:

[0043]

[0044] in,

[0045] E is the kinetic energy of the broken blade portion in the multi-layer casing, N·m;

[0046] M is the mass of the broken blade part in the multi-layer casing, kg;

[0047] N is the blade speed in the multi-layer casing, r / min;

[0048] R C is the radius of the center of mass of the broken part of the blade in the multi-layer casing, m.

[0049] By comparing the destruction potential energy A of the multi-layer casing with the kinetic energy E of the broken blade part, it can be determined whether the containment capacity of the multi-layer casing meets the containment design requirements.

[0050] Compare the kinetic energy of the broken blade part with the casing destruction potential energy, and determine whether the containment requirements are met according to the criteria.

[0051] In the aircraft engine multi-layer casing containment design method disclosed in the above embodiment, when calculating the containment capacity of the multi-layer casing, the wall thickness and material properties of the multi-layer casing are converted proportionally, and the multi-layer casing is equivalent to a single-layer casing for calculation. It has been verified by experiments that it has high accuracy and is convenient for analyzing the impact of the material differences of each layer of the casing on the containment capacity, which is convenient for the design and improvement of the multi-layer casing. Based on this design of the containment of the multi-layer casing, the casing wall thickness can be avoided to be too thick, the overall quality of the aircraft engine is reduced, and the thrust-to-weight ratio of the aircraft engine is improved.

[0052] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for designing the containment of a multi-layer casing of an aircraft engine, characterized in that: include: Extract multi-layer casing wall thickness and material properties; Equivalent conversion of multi-layer casing wall thickness: Where h is the equivalent wall thickness of the multi-layer casing; i is the number of layers of the multi-layer casing; h i is the thickness of the i-th layer casing; Equivalent conversion of multi-layer casing material performance: Where σ is the equivalent material performance of the multi-layer casing; α i is the material property of the i-th layer casing; The containment capacity of the multi-layer casing is calculated based on the equivalent wall thickness h and the equivalent material performance σ of the multi-layer casing; Evaluate whether the containment capacity of the multi-layer casing meets the containment design requirements. If not, adjust the design of the multi-layer casing until the containment capacity of the multi-layer casing meets the containment design requirements.

2. The multi-layer casing containment design method according to claim 1, characterized in that: Material properties include material shear strength.

3. The multi-layer casing containment design method according to claim 1, characterized in that: When the containment capacity of the multi-layer casing does not meet the containment design requirements, adjust the design of the multi-layer casing, including: Increase the wall thickness of the receiver; Replace the material of the receiver; Add reinforcement ribs to the receiver; A containment ring is added to the receiver.

4. The multi-layer casing containment design method according to claim 1, characterized in that: Based on the equivalent wall thickness h of the multi-layer casing and the equivalent material performance σ of the multi-layer casing, the containment capacity of the multi-layer casing is calculated as follows: A=Lh 2 t D (0.5K+n); in, A is the potential energy of multilayer casing failure, N·m, which represents the containment capacity of the multilayer casing; L is the perimeter of the section of the outer edge of the blade colliding with the multi-layer casing, m; τ D is the equivalent dynamic strength shear limit of the multilayer casing material, MPa. When data is missing, take τ D =1.3τ b , τ b is the equivalent static shear strength limit of the multi-layer casing material; K is the empirical coefficient of bending deformation. When there is a lack of specialized experience, it is taken as 2.5; n is the empirical coefficient of shear deformation. When there is a lack of specialized experience, it is taken as 0.

7.

5. The multi-layer casing containment design method according to claim 1, characterized in that: When evaluating whether the containment capacity of a multi-layer casing meets the containment design requirements, the kinetic energy of the broken blade portion in the multi-layer casing is calculated as: in, E is the kinetic energy of the broken blade portion in the multi-layer casing, N·m; M is the mass of the broken blade part in the multi-layer casing, kg; N is the blade speed in the multi-layer casing, r / min; R C is the radius of the center of mass of the broken part of the blade in the multi-layer casing, m.

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