Method for evaluating sealing performance of shaft neck and disc connecting bolt

Abstract

The invention provides a shaft neck and disc connecting bolt sealing performance evaluation method. The method comprises the steps that 1, the specification and the number of connecting pieces are preliminarily determined; 2, establishing a three-dimensional finite element model; 3, simulating a contact part of the connecting piece and the connected piece by adopting a contact unit, and simulating an initial pre-tightening load of the connecting piece by applying interference magnitude to the axial matching end surfaces of the connecting piece and the connected piece; 4, finite element analysis under initial pre-tightening is carried out, and numerical values of the compression amount L1 of the connected piece and the elongation amount L2 of the connecting piece are obtained; step 5, when L1 is less than L2, entering step 6; otherwise, adjusting the specification of the connecting piece and returning to execute the step 1; step 6, obtaining an extrusion force result F of each node of the axial mounting edge of the connected piece and an axial deformation difference delta U of the node at the corresponding position of the axial mounting edge of the connected piece; step 7, if F is not less than 0 and delta Uis not greater than 0, indicating that the sealing performance of the axial mounting edge of the connected piece meets the requirement; otherwise, returning to execute the step 1.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engines, and in particular to a method for evaluating the sealing performance of a bolt connecting a journal and a disc. Background Art

[0002] Bolt connection structures are widely used between aircraft engine disks and disks, and between journals and disks, and torque is transmitted through end face friction. In order to ensure reliable connection and increase the service life of the bolts, no axial separation of the mounting edge is allowed during operation. At present, conventional methods are used to evaluate the sealing of the mounting edge of the connecting bolts between rotors. It is applicable to use conventional methods to evaluate the sealing of the connected parts (disks) with matching stiffness and coordinated deformation.

[0003] As for the bolt structure connecting the journal and the disc, there is a difference in radial rigidity between the journal and the disc. Under the working load, the journal is prone to axial separation from the center line of the bolt hole to the inner mounting edge of the journal due to bending deformation. Since the existing conventional methods cannot effectively consider the stiffness of the connected parts and fail to consider the influence of the incoordination of the deformation of the connected parts, the bolt connection structure designed by the conventional method may have local axial separation of the mounting edge under working conditions. The local axial separation of the mounting edge further causes the bolts to loosen, resulting in fatigue failure of the bolts, which poses a serious threat to the safe operation of the engine. There is a risk of not meeting the use requirements according to the existing conventional methods. Summary of the invention

[0004] In view of this, an embodiment of the present specification provides a method for evaluating the sealing performance of the bolts connecting the journal and the disc, which has achieved the purpose of improving the reliability of the evaluation.

[0005] The embodiments of this specification provide the following technical solutions: a method for evaluating the sealing performance of the connecting bolts between the journal and the disk, comprising the following steps: Step 1: preliminarily determine the specifications and quantity of the connecting parts on the premise that the sealing performance of the installation edge meets the design requirements; Step 2: establish a three-dimensional finite element model based on the specifications and quantity of the connecting parts, so that the three-dimensional finite element model includes the connecting parts and the connected parts; Step 3: in the established three-dimensional finite element model, the contact unit is used to simulate the contact part between the connecting parts and the connected parts, and the connection is simulated by applying an interference fit to the axial mating end faces of the connecting parts and the connected parts. Initial preload of the connecting part; Step 4: According to the initial preload of the connecting part, perform finite element analysis under initial preload, and obtain the values ​​of the compression amount L1 of the connected part and the elongation amount L2 of the connecting part; Step 5: Compare the compression amount L1 of the connected part and the elongation amount L2 of the connecting part. When L1<L2, proceed to Step 6; otherwise, adjust the specifications of the connecting part and return to Step 1; Step 6: Perform finite element analysis under working load to obtain the extrusion force result F of each node of the axial installation side of the connected part and the axial deformation difference of the node at the corresponding position of the axial installation side of the connected part ΔU; Step 7: If |F|≮0 and Δ When U≯0, it indicates that the sealing performance of the axial mounting edge of the connected part meets the requirements; otherwise, adjust the specifications of the connecting part and the stiffness of the connected part, and return to step 1.

[0006] Compared with the prior art, at least one of the above-mentioned technical solutions adopted in the embodiments of this specification can achieve at least the following beneficial effects: the present invention can accurately evaluate the sealing design of the connection structure between the journal and the disc of the aircraft engine, avoid local separation of the installation edge, and improve the reliability of the connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0008] Figure 1 It is a schematic diagram of a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0009] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0010] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0011] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0012] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0013] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0014] like Figure 1 As shown, an embodiment of the present invention provides a method for evaluating the sealing performance of a journal-disc connection bolt, which specifically includes the following steps:

[0015] (1) Evaluate the sealing performance of the installation edge using conventional methods and determine the bolt specifications based on the premise that it meets the design requirements.

[0016] (2) Based on the number of bolts n preliminarily determined in step (1), take 1 / n sectors of the connected parts to establish a three-dimensional finite element model. The finite element model must include the connected parts and the connecting parts.

[0017] (3) In the finite element model established in step (2), the contact parts of each part need to be simulated using contact units, and the bolt preload Fy is simulated by applying an axial interference to the mating end faces of the nut and the connected part (the interference needs to be determined through iteration. First, an initial interference of a (generally a < 0.2 mm) is applied, and then the nut end face support reaction force result Fz is extracted, and the required interference data is obtained based on a × Fy / Fz).

[0018] (4) Based on step (3), only room temperature load is applied to obtain the finite element results under the initial preload.

[0019] (5) From the results of step (4), extract the data of the compression amount L1 of the connected part and the elongation amount L2 of the bolt respectively.

[0020] (6) In order to reduce the working load of the connecting parts and improve the reliability of the connecting parts, it is necessary to ensure that the stiffness of the connected parts is greater than the stiffness of the connecting parts. Therefore, if L1<L2, a finite element analysis is performed under the working state; otherwise, the bolt specifications need to be adjusted, and then the work content of steps (1) to (5) is performed.

[0021] (7) The bolt specification adjustment method in step (6) is to reduce the bolt nominal diameter d and the hole diameter of the connected part to obtain the minimum arc length L3 between the hole of the connected part and the hole edge. In order to improve the sealing performance of the installation edge and ensure the life of the hole edge of the connected part, d <L3<8d。

[0022] (8) When performing finite element analysis under working conditions, the selected analysis conditions should include but not be limited to the maximum aerodynamic and maximum temperature conditions. The loads mainly consider temperature, rotation speed, and axial force.

[0023] (9) After obtaining the finite element results under the working state, the extrusion pressure results F of each node on the axial mounting edge of the journal or wheel disc and the axial displacement results Ud and Ua at the corresponding positions of the wheel disc and the journal mounting edge are extracted respectively. The axial deformation difference ΔU=Ua-Ud (the axial deformation is defined as backward as positive) of the nodes at the corresponding positions of the mounting edge is calculated based on Ud and Ua.

[0024] (10) If the absolute value of the extrusion pressure at each node of the installation edge |F|≮0 and ΔU≯0, it indicates that the sealing of the installation edge meets the requirements. Otherwise, it is necessary to adjust the bolt specifications (generally reduce the nominal diameter of the bolts and increase the number of bolts) and optimize the stiffness of the connected parts (ensure that the deformation of the journal and the disc matches), and then perform the work content of the above steps.

[0025] The beneficial effects of the present invention are:

[0026] (1) The evaluation method provided by the present invention can accurately evaluate the sealing design of the connection structure between the journal and the disk of an aircraft engine, avoid the local separation phenomenon of the installation edge, and improve the reliability of the connection;

[0027] (2) The present invention provides a method for adjusting bolts, providing guidance for the design of connectors;

[0028] (3) The evaluation method provided by the present invention is easy to operate and has strong engineering operability.

[0029] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment described later, since it corresponds to the system, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment.

[0030] 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 evaluating the sealing performance of a journal-disc connection bolt, characterized in that: The following steps are involved: Step 1: Evaluate the sealing performance of the installation edge and determine the specifications and quantity of the connectors. Step 2: Establish a three-dimensional finite element model according to the specifications and quantity of the connecting parts, so that the three-dimensional finite element model includes the connecting parts and the connected parts; Step 3: In the established three-dimensional finite element model, the contact unit is used to simulate the contact part between the connector and the connected part, and the initial preload of the connector is simulated by applying interference to the axial mating end faces of the connector and the connected part; Step 4: According to the initial preload of the connector, perform finite element analysis under initial preload, and obtain the values ​​of the compression amount L1 of the connected component and the elongation amount L2 of the connector; Step 5: Compare the compression amount L1 of the connected part and the elongation amount L2 of the connecting part. When L1 < L2, proceed to step 6; otherwise, adjust the specification of the connecting part and return to step 1. Step 6: Perform finite element analysis under working load to obtain the extrusion force result F of each node on the axial installation side of the connected part and the axial deformation difference of the node at the corresponding position on the axial installation side of the connected part. Δ U; Step 7: If |F|≮0 and Δ When U≯0, it indicates that the sealing performance of the axial mounting edge of the connected part meets the requirements; otherwise, adjust the specifications of the connecting part and the stiffness of the connected part, and return to step 1.

2. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 1, characterized in that: The step 2 specifically includes: according to the initially determined number of connectors n, taking 1 / n connected component sectors to establish a three-dimensional finite element model, and making the three-dimensional finite element model include the connected components and the connectors.

3. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 2, characterized in that: In step 3, the preload of the connector is simulated by applying an interference fit on the axial mating end faces of the connector and the connected component. Specifically, an initial interference fit of a is applied, and the reaction force result Fz of the connector end face is extracted. The required interference fit data is obtained according to the formula a*Fy / Fz, where a<0.2mm and Fy is the initial preload of the connector.

4. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 3, characterized in that: When the finite element analysis under initial preload is performed in step 4, only room temperature load is applied to calculate the finite element results under the initial preload, and the values ​​of the compression amount L1 of the connected part and the elongation amount L2 of the connecting part are obtained.

5. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 4, characterized in that: The specification of the connecting piece is adjusted in step 5 as follows: reducing the nominal diameter d of the connecting piece and the hole diameter of the connected piece, obtaining the minimum arc length L3 between the hole of the connected piece and the hole edge, and satisfying d <L3<8d。 6. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 5, characterized in that: When performing the finite element analysis calculation under the working load in step 6, the selected analysis conditions include the maximum aerodynamic and maximum temperature states; the selected analysis loads include temperature, rotation speed and axial force.

7. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 6, characterized in that: The connected parts are a wheel disc and a journal. When performing finite element analysis under working load, the axial displacement result Ud of the axial installation edge of the wheel disc and the axial displacement result Ua of the matching position of the journal are obtained. The formula Δ U=Ua-Ud, calculate the axial deformation difference of the node at the corresponding position of the axial installation edge of the connected part Δ U.

8. A method for evaluating the sealing performance of a journal-disc connection bolt according to claim 7, characterized in that: The specific steps of step 7 are as follows: The adjusting of the specifications of the connecting parts includes: reducing the nominal diameter of the connecting parts and increasing the number of the connecting parts; The adjusting the rigidity of the connected member includes: making the wheel disc and the journal deform and match each other.

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