A method for describing the position distribution of a sealing ring under multi-scale assembly factors of a flared joint

Abstract

The application discloses a sealing ring position distribution description method under a multi-scale assembly factor of a flared joint, establishes a multi-scale manufacturing and assembly factor fusion model containing a matching angle, a radial circle runout and a half-flared angle; a reference coordinate system is established with the center of a circle intersecting a tapered surface and a cylindrical surface in the flared pipe as an origin, a macroscopic matching angle is represented by rigid body rotation, a mesoscopic radial circle runout is represented by a radius of a point on a generatrix of the tapered surface of the pipe joint, and a mesoscopic half-flared angle is represented based on a spherical coordinate; a coordinate of a contact point at the top of the edge of the flared pipe is located, a local analytical model is established to represent an intermediate parameter angle changing with the matching angle, and finally, a relative contact position of a contact area of the flared pipe and the pipe joint is determined as an initial boundary condition of a microcosmic finite element contact model. The application can provide an accurate initial contact state and boundary condition for a contact model with a microcosmic morphology, and improve the prediction accuracy of sealing performance.

Description

Technical Field

[0001] This application belongs to the field of sealing ring technology, specifically relating to a method for describing the position distribution of sealing rings under multi-scale assembly factors of flared joints. Background Technology

[0002] The sealing performance of aviation hydraulic systems is one of the key aspects of normal aircraft operation, directly affecting the aircraft's safety and reliability. System leaks can not only lead to a decline in flight performance but also cause serious safety problems, even resulting in catastrophic consequences such as aircraft incapacitation. As an indispensable core component of the hydraulic system, the sealing performance and structural reliability of flared pipe fittings are directly related to the overall safety of the aircraft, playing an irreplaceable and vital role in practical applications.

[0003] The sealing performance of flared pipe joints is closely related to the actual contact state of their sealing interface. To study the sealing mechanism in depth, a full-scale finite element simulation model is usually used for simulation analysis. This modeling method can comprehensively consider macroscopic geometry and microscopic surface morphology features. However, the full-scale finite element model needs to cover multiple scales, which leads to a sharp increase in the number of meshes, resulting in problems such as excessive computation time and significantly increased costs.

[0004] In engineering applications, to reduce solution complexity and improve analysis efficiency, a simplification strategy is commonly adopted, which involves constructing representative microscale elements to characterize the microscopic sealing interface contact state at the edge of the flared pipe. By reducing the number of meshes, this simplification strategy significantly improves computational speed while maintaining a certain level of simulation accuracy. However, in prediction scenarios involving manufacturing and assembly deviations, the combined effects of multiple scale factors, such as mating angles, radial runout, and half-flaring angles, result in significant non-uniformity in the distribution of the sealing ring along the circumferential direction. The initial contact coordinates and mechanical boundary conditions corresponding to different circumferential angle positions are difficult to accurately define, directly affecting the reliability of the input parameters for the microscopic contact model. Existing analytical methods have failed to establish a clear numerical mapping relationship between multi-scale assembly factors and the spatial position of the sealing ring, making it impossible to provide accurate initial boundary conditions for microscopic contact simulation. This leads to a significant deviation between the predicted sealing performance and the actual physical process. Summary of the Invention

[0005] To overcome the problem in existing technologies where the spatial distribution of the sealing ring is difficult to quantitatively characterize due to the coupling effect of multiple scale factors such as mating angle, radial runout, and half-flaring angle, this invention aims to provide a method for describing the positional distribution of the sealing ring under multiple assembly factors of a flared joint, thereby achieving accurate determination of the initial boundary conditions of the microscale contact model.

[0006] To achieve the above technical objectives, this application specifically employs the following technical solution: In one aspect of this application, a method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint is provided, comprising the following steps: S1. Divide the manufacturing and assembly factors into multiple scales, including the mating angle of the macro scale, the radial runout of the meso scale, and the half-flare angle of the meso scale. S2. Establish a reference coordinate system with the center point O of the flared pipe as the origin, align the pipe joint axis with the z-axis of the reference coordinate system, and rotate the flared pipe around the y-axis of the reference coordinate system by a fitting angle α to characterize the assembly error. S3. The mating angle on a macroscopic scale is characterized by rotating the flared tube around its center point O in a manner corresponding to the mating angle α. S4. The radial circular runout J at the mesoscale is characterized by determining the radius of a point E on the generatrix of the pipe joint cone; the coordinates of point E are determined based on the position of reference point C on the pipe joint cone. S5, locating the spherical coordinates of point A on the flared pipe ( r A , i A , ); S6. Position coordinates of the top contact point B on the edge of the flared pipe ( r B , i B , ), representing the half-flare angle γ at the mesoscopic scale; S7. Establish a local analytical model, and characterize the intermediate parameter angle δ as it varies with the coordination angle α using the following formula: ; S8. Based on the position coordinates of the top contact point B at the edge of the flared pipe ( r B , i B , The relative contact position between the flared pipe and the pipe joint is determined by the intermediate parameter angle δ, and the relative contact position is used as the initial boundary condition of the micro finite element contact model.

[0007] In one implementation, the radius of the point on the generatrix of the pipe joint conical surface is determined in step S4 using the following formula. :

[0008] in, For the pipe fitting, a semi-flared angle, The distance between line segment CE is... Let C be the radius length. This represents the height of point C from the origin O.

[0009] In one implementation, the spherical coordinates of a point A on the flared tube are characterized in step S5 by the following formula:

[0010]

[0011] in, Let OA be the length of line segment OA. The angle between line OA and the z-axis. For intermediate parameter angle, For matching angles, The circumferential angle corresponding to the contact point.

[0012] In one implementation, the position coordinates of the top contact point B of the flared tube edge are located in step S6 using the following formula ( r B , i B , ):

[0013]

[0014] in, Let OA be the length of line segment OA. Let AB be the length of line segment AB. To create a deviation angle for the half-widened mouth angle, The angle between lines OA and OB is... For intermediate parameter angle, For matching angles, The circumferential angle corresponding to the contact point.

[0015] In one implementation, step S7 is characterized by the following formula, which represents the variation with the mating angle. Changing intermediate parameter angle :

[0016] in, The circumferential angle corresponding to the contact point.

[0017] In one implementation, the intermediate parameter angle Satisfying the relation:

[0018] in, Let O' be the height corresponding to the edge point of the flared pipe in the O' coordinate system, where O' is the center of the circle containing the top contact point B of the flared pipe edge. ' is the radius from the top contact point B to O of the flared pipe edge. The distance from the edge point of the flared pipe to the y-axis is denoted by y.

[0019] In one implementation, in step S2, the positive x-direction of the reference coordinate system is defined as the 90° circumferential angle direction, and the negative x-direction of the reference coordinate system is defined as the -90° circumferential angle direction.

[0020] In one implementation, step S2 involves selecting the cross section corresponding to a circumferential angle of 90° for multi-scale factor fusion positioning analysis.

[0021] In one implementation, the mating angle It is 1°.

[0022] In one implementation, the pipe fitting has a semi-flared angle. It is 37°.

[0023] In one implementation, the radius of point A on the flared pipe It is 8mm.

[0024] In one implementation, the length of line segment AB is... It is 4.04mm.

[0025] In one embodiment, the method of this application is applied to the sealing mechanism analysis of flared pipe joints in aviation hydraulic systems.

[0026] The beneficial effects of this application are as follows: The proposed method and simplified modeling have demonstrated significant effectiveness in analyzing the sealing performance of flared pipe joints. By characterizing the spatial distribution of the sealing ring through analytical description, accurate initial relative contact states and boundary conditions are provided for representative microscale units, significantly improving computational efficiency while ensuring high accuracy of simulation results. The proposed method effectively addresses the uncertainties caused by multi-scale manufacturing and assembly errors, providing a reliable theoretical basis for subsequent optimization design. Especially under complex assembly conditions, by rationally defining contact model parameters, the accuracy of sealing performance prediction is significantly improved, providing an efficient and accurate technical solution for practical engineering applications. Attached Figure Description

[0027] Figure 1 This is a description of the sealing ring position of the flared pipe joint in this application embodiment; Figure 2 This is a schematic diagram illustrating the influencing factors of multi-scale assembly in an embodiment of this application; Figure 3 This is a schematic diagram of the pipe fitting positioning according to an embodiment of this application; Figure 4 This is a schematic diagram of the flared tube positioning in an embodiment of this application; Figure 5 This is a schematic diagram of the edge position of the flared tube in an embodiment of this application. Detailed Implementation

[0028] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] This application provides a method for describing the position distribution of the sealing ring under multi-scale assembly factors in a flared joint. By classifying and analyzing the multi-scale influencing factors on the sealing ring position distribution, the main factors causing uncertainty in the sealing ring distribution and changes in the initial contact state of the contact cone surface include the mating angle α involved in the joint tightening assembly process, the radial runout J involved in the manufacturing process of the components of the pipe joint connection structure, and the half-flare angle. The influence of multi-scale factors on the initial state of the contact cone surface is characterized parametrically, exploring the distribution law of the initial relative positions of the contact bodies under the influence of multi-scale factors, and thus determining the initial boundary conditions of the two contact bodies in the micro-finite element contact model.

[0030] Specifically, the method for describing the position distribution of the sealing ring under multi-scale assembly factors of the flared joint in this application is achieved through the following steps: Step 1: Establish a reference coordinate system The origin of the coordinate system is denoted as point O, with the center of the intersection line between the conical and cylindrical surfaces inside the flared pipe as the origin. In the reference coordinate system, the positive x-axis points towards the 90° circumferential angle, and the negative x-axis points towards the -90° circumferential angle. The pipe joint axis coincides with the z-axis of the reference coordinate system. The flared pipe is rotated around the y-axis of the reference coordinate system by an angle equal to the mating angle α. This rotation operation characterizes the mating angle error generated during the assembly process of the flared pipe. After the rotation operation, the axis of the flared pipe lies in the xOz plane of the reference coordinate system. The section corresponding to the 90° circumferential angle is selected as the analysis section, and a multi-scale fusion positioning analysis of manufacturing and assembly factors is performed on this section.

[0031] Step 2: Characterization of Macroeconomic Factors Based on the dimensional classification results of assembly and manufacturing factors, the macroscopic dimensional factor mating angle α is characterized according to the rigid body rotation method in step one. Taking the pipe fitting as the reference object, the flared pipe is rotated around the center point O of the flared pipe by an angle, the magnitude of which is equal to the mating angle α. The above rotation operation is used to characterize the mating angle error generated by the flared pipe in the actual assembly state.

[0032] Step 3: Characterization of mesoscopic factors (radial runout) In the mesoscopic scale, radial runout J is characterized in the pipe joint structure. It is represented by the radius corresponding to point E on the generatrix of the pipe joint's conical surface. Point E can be determined based on the coordinates of point C, defined by the following formula:

[0033]

[0034] In the formula: This represents the angle between the generatrix CE of the conical surface of the pipe joint and the vertical z-axis, i.e., the half-flare angle of the pipe joint; e represents the distance of line segment CE; c represents the radius length corresponding to point C; h represents the height of point C from the origin.

[0035] Step 4: Characterization of mesoscopic factors (half-widened mouth corner) Mesoscale pipe joint semi-flare angle In the flared tube structure, the semi-flaring angle affects the spatial position of the top contact point B on the flared tube edge. It can be spatially located based on the coordinates of point A, where the spherical coordinates of point A are A( r A , i A , It can be characterized by the following formula:

[0036]

[0037] In the formula: Indicates the length of line segment OA; This represents the angle between line OA and the z-axis; Indicates the intermediate parameter angle; Indicates the fitting angle; This indicates the circumferential angle corresponding to the contact point.

[0038] Step 5: Locating the edge points of the flared tube Because the pipe fitting assembly structure is symmetrical about the xOz plane, only the distribution of relative contact positions within the range of -90° to 90° is studied. The contact point B at the top of the flared pipe edge (…). r B , i B , The position coordinates of a point can be defined using the following formula:

[0039]

[0040] In the formula: Let OA be the length of line segment OA; Let AB be the length of line segment AB; To create a deviation related to the angle of the half-flared mouth; The angle between lines OA and OB; Angle as an intermediate parameter; For the mating angle; The circumferential angle corresponding to the contact point.

[0041] Step 6: Characterization of intermediate parameters angle i A and i B This involves two angles: a constant angle ω related to the flared pipe structure and an angle δ that varies non-linearly with the mating angle α. A local analytical model is established to reveal the relationship between the mating angle α and the angle δ:

[0042]

[0043] In the formula: This refers to the height corresponding to the edge point of the flared pipe. ' is the radius from the top contact point B to O on the edge of the flared pipe; The distance from the projection of the edge point of the flared pipe onto the axis.

[0044] This is the distance from the edge point of the flared pipe projected to the origin.

[0045] Thus, the relative contact positions of the flared pipe and pipe joint contact areas, encompassing multi-scale manufacturing and assembly factors during the contact process, have been determined. These relative contact positions constitute the boundary conditions of the micro-finite element contact model. Based on these determined boundary conditions, a contact model with microscopic morphology can be established, and the formation mechanism of the micro-sealing interface can be further explored.

[0046] Example Reference Figure 1As shown, the description process for the sealing ring position of the flared pipe fitting is as follows: The distribution of sealing ring positions is analyzed for an M24 mm × 1.5 mm aviation flared pipe fitting. Specific parameters are shown in Table 1. Table 1 Flared pipe fittings and piping parameters

[0047] Step 1: Classification and Analysis of Multi-Scale Influencing Factors on the Distribution of Sealing Ring Position The main factors causing uncertainty in the distribution of the sealing ring and changes in the initial contact state of the contact cone surface include not only the mating angles involved in the tightening and assembly process of the joint. α It also includes radial runout involved in the manufacturing process of components of pipe fitting connection structures. J By parametrically characterizing the influence of multi-scale factors on the initial state of the contact cone surface and the half-expansion angle, we can explore the initial relative position distribution of the contact bodies under the influence of multi-scale factors, and then determine the initial boundary conditions of the two contact bodies in the micro finite element contact model.

[0048] Step 2: Establish a reference coordinate system A coordinate system is established with the center O of the intersection line between the conical surface and the cylindrical surface inside the flared pipe as the origin. The positive x-direction is the circumferential angle 90°, and the negative x-direction is the direction corresponding to the circumferential angle -90°. The axis of the pipe joint coincides with the z-axis.

[0049] Step 3: Characterization of Macroeconomic Factors Based on the results of the assembly manufacturing factor scale division, the macro-scale factor coordination angle α by Figure 2 The rigid body rotation method shown is characterized by rotating the flared tube around the y-axis by a specific angle. α To characterize assembly errors and ensure that the axis of the flared pipe is within the xOz plane, a multi-scale factor fusion positioning analysis is performed on the section corresponding to a circumferential angle of 90°.

[0050] Step 4: Characterization of mesoscopic factors (radial circular runout) like Figure 3 As shown, radial circular runout in mesoscale factors J In the pipe joint structure, the radial runout is characterized by the radius corresponding to point E on the generatrix of the pipe joint's conical surface. Point E can be determined based on the coordinates of point C, defined by the following formula: =10.48 mm

[0051] In the formula: The angle between the generatrix CE of the conical surface of the pipe joint and the vertical z-axis is the half-flare angle of the pipe joint. e The distance between line segment CE; c The radius length corresponding to point C; h This represents the height of point C from the origin. The angle between OB, OE and the z-axis; Step 5: Characterization of mesoscopic factors (half-widened mouth corner) Mesoscale pipe joint semi-flare angle Characterized in flared tube structures, such as Figure 4 As shown, the semi-flaring angle affects the spatial position of the top contact point B on the edge of the flared pipe. It can be spatially located based on the coordinates of point A. The spherical coordinates of point A are A( r A , i A , It can be characterized by the following formula:

[0052]

[0053] In the formula: a —Length of line segment OA; i A —The angle between line OA and the z-axis; —The contact point corresponds to the circumferential angle; Step Six: Locating the Edge Points of the Flared Pipe Because the pipe fitting assembly structure is symmetrical about the xOz plane, only the distribution of relative contact positions within the range of -90° to 90° is studied. The contact point B at the top of the flared pipe edge (…). r B , i B , The position coordinates of a point can be defined using the following formula:

[0054]

[0055] In the formula: b —Length of line segment AB; oh—— The angle between lines OA and OB; —The angle related to the manufacturing deviation of the semi-expanded mouth corner.

[0056] Step 7: Characterization of intermediate parameters angle i A and i B Related to two angles: a constant angle related to the flared tube structure. oh (The values ​​are shown in Table 1) and with the coordination angle α Angle of nonlinear change d .like Figure 5 As shown, establishing a local analytical model reveals the fitting angle. α With angle d Relationship between them:

[0057]

[0058]

[0059] In the formula: l =0.0020 mm is the height corresponding to point B on the edge of the flared pipe; m =9.74 mm is the distance from point B on the edge of the flared pipe projected to the origin; n =6.89 mm is the distance from point B on the edge of the flared pipe projected onto the axis; This is the angle corresponding to the projection, which is 45° here; To match the angle, we take 1° here.

[0060] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A method for describing the position distribution of sealing rings under multi-scale assembly factors of a flared joint, characterized in that, Includes the following steps: S1. Divide the manufacturing and assembly factors into multiple scales, including the mating angle of the macro scale, the radial runout of the meso scale, and the half-flare angle of the meso scale. S2. Establish a reference coordinate system with the center point O of the flared pipe as the origin, align the pipe joint axis with the z-axis of the reference coordinate system, and rotate the flared pipe around the y-axis of the reference coordinate system by a fitting angle α to characterize the assembly error. S3. The mating angle on a macroscopic scale is characterized by rotating the flared tube around its center point O in a manner corresponding to the mating angle α. S4. The radial circular runout J at the mesoscale is characterized by determining the radius of a point E on the generatrix of the pipe joint cone; the coordinates of point E are determined based on the position of reference point C on the pipe joint cone. S5, locate the spherical coordinates of point A on the flared pipe ( r A , θ A , ); S6. Position coordinates of the top contact point B on the edge of the flared pipe ( r B , θ B , ), representing the half-expansion angle at the mesoscopic scale; S7. Establish a local analytical model to characterize the intermediate parameter angle δ as it varies with the coordination angle α; S8. Based on the position coordinates of the top contact point B at the edge of the flared pipe ( r B , θ B , The relative contact position between the flared pipe and the pipe joint is determined by the intermediate parameter angle δ, and the relative contact position is used as the initial boundary condition of the micro finite element contact model.

2. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S4, the radius of the point on the generatrix of the conical surface of the pipe joint is determined using the following formula. : in, For the pipe fitting, a semi-flared angle, The distance between line segment CE is... Let C be the radius length. This represents the height of point C from the origin O.

3. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S5, the spherical coordinates of point A on the flared tube are represented by the following formula: in, Let OA be the length of line segment OA. The angle between line OA and the z-axis. For intermediate parameter angle, For matching angles, The circumferential angle corresponding to the contact point.

4. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S6, the position coordinates of the top contact point B of the flared pipe edge are located using the following formula ( r B , θ B , ): in, Let OA be the length of line segment OA. Let AB be the length of line segment AB. To create a deviation angle for the half-widened mouth angle, The angle between lines OA and OB is... For intermediate parameter angle, For matching angles, The circumferential angle corresponding to the contact point.

5. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S7, the following formula characterizes the variation with the coordination angle. Changing intermediate parameter angle : in, The circumferential angle corresponding to the contact point.

6. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 5, characterized in that, Intermediate parameter angle Satisfying the relation: in, The height corresponding to the edge point of the flared pipe. ' is the radius of the contact point B at the top of the flared pipe edge. The distance from the edge point of the flared pipe to the y-axis is denoted by y.

7. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S2, the positive x-direction of the reference coordinate system is defined as the 90° direction of the circumferential angle, and the negative x-direction of the reference coordinate system is defined as the -90° direction of the circumferential angle.

8. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, In step S2, the section corresponding to the circumferential angle of 90° is selected for multi-scale factor fusion positioning analysis.

9. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, Matching angle It is 1°.

10. The method for describing the position distribution of the sealing ring under multi-scale assembly factors of a flared joint according to claim 1, characterized in that, Pipe fitting semi-flared angle It is 37°.

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