Method for sizing a planar mesh model of a retaining chamfer feature

Abstract

This invention provides a method for adjusting the size of a planar mesh model while preserving chamfer features, comprising the following steps: S1, inputting a planar mesh model; S2, extracting planar information from two adjacent planes P1 and P2 that form a chamfer with the plane to be moved P0; S3, establishing a coordinate system x according to the right-hand rule based on the extracted planar information. 0 y 0 z 0 x 1 y 1 z 1 S4. Determine the region of mesh nodes to be moved based on the established coordinate system; S5. Use the node-moving slicing method to move all nodes within the mesh node region; S6. After updating the coordinates of all nodes to be moved, output the adjusted planar mesh model. This invention can move nodes in adjacent areas of a plane using a slicing method, achieving rapid adjustment of the planar dimensions without needing to modify the planar position and re-mesh in 3D modeling software. In analyses related to planar dimensions, sensitivity, reliability, etc., only one meshing is required, improving analysis efficiency.

Description

Technical Field

[0001] This invention relates to the fields of blade mesh model size optimization and sensitivity analysis, and particularly to a method for adjusting the size of a planar mesh model while maintaining chamfer features. Background Technology

[0002] In existing technologies, aero-engine turbine blades are typically connected to the turbine disk using a tenon joint, achieving a tight fit under centrifugal force. Fretting fatigue caused by stress concentration on the tenon joint surface is the main cause of tenon fracture failure.

[0003] Therefore, the dimensions of the mating plane at the tenon joint are a crucial factor that must be considered during the design process of blade life assessment, reliability calculation, and dimensional tolerance determination. Currently, the analysis process for the dimensions of the mating surface at the tenon joint involves adjusting the dimensions using 3D modeling software. Then, the model is imported into mesh generation software to re-mesh, and finally, the modified mesh model is imported into finite element analysis software for calculation and analysis.

[0004] Due to the complexity of the blade model and the stringent requirements for the quality of the mesh on the contact tenon joint mating surface during finite element analysis, each time the dimensions are adjusted in the 3D modeling software, the mesh needs to be re-divided, which consumes a huge amount of manpower and time resources, seriously affecting the efficiency of blade design.

[0005] The connection between turbine blades and turbine disks in aero-engines is usually a tenon joint. The dimensions of the tenon and mortise plane affect the pressure distribution characteristics of the mating surface of the tenon joint. Clarifying the impact of the mating surface dimensions on blade reliability and fretting fatigue life is an important basis for determining the mating surface dimensions and optimizing the mating surface.

[0006] Current technology involves modifying the dimensions of the mating surfaces in 3D modeling software and then importing the modified surface into meshing software to re-mesh. Due to the complexity of blade models and the stringent requirements of finite element contact analysis on the contact surface mesh, each re-meshing process consumes significant manpower, time, and computational resources. Furthermore, reliability and sensitivity analyses over lifespan require solving for stress-strain distribution data under various mating surface dimensions, posing a major challenge to the design optimization of aero-engine blades and turbine disks.

[0007] Figure 1 This is a schematic diagram of the planar adjustment area. (Example) Figure 1 As shown, adjustments are made to the planar dimensions (see appendix). Figure 1 , where P_1 P_2) The problem of inefficiency caused by the need to re-mesh the grid.

[0008] In view of this, regarding the problem of adjusting the planar dimensions of the tenon joint, the inventors of this application have designed a method for adjusting the dimensions of a planar mesh model while maintaining the chamfer feature. The technical problems to be solved in this process include:

[0009] (1) The problem of moving grid nodes in a planar region, as shown in the attached figure. Figure 1 As shown in region I;

[0010] (2) Problem of mesh node movement in chamfered region, as shown in the attached figure. Figure 1 As shown in region II. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, such as the huge amount of manpower and time resources required for re-meshing the blade model, which seriously affects the efficiency of blade design, and to provide a method for adjusting the size of a planar mesh model while maintaining the chamfer feature.

[0012] The present invention solves the above-mentioned technical problems through the following technical solution:

[0013] A method for adjusting the size of a planar mesh model while maintaining chamfer features, characterized in that the method includes the following steps:

[0014] S1. Input planar mesh model;

[0015] S2. Extract the planar information of two adjacent planes P1 and P2 that form a chamfer with the plane P0 to be moved;

[0016] S3. Based on the extracted planar information, establish a coordinate system x according to the right-hand rule. 0 y 0 z 0 x 1 y 1 z 1 ;

[0017] S4. Determine the area of ​​the grid nodes to be moved based on the established coordinate system;

[0018] S5. Using the node-moving slicing method, all nodes are moved within the grid node region;

[0019] S6. After updating the coordinates of all nodes to be moved, output the adjusted planar mesh model.

[0020] According to an embodiment of the present invention, step S3 includes: coordinate system x 0 y 0 z 0 x 1 y 1 z 1The z-axis of each coordinate system is perpendicular to planes P0 and P1, respectively, and the y-axis of both coordinate systems is perpendicular to the line of intersection of planes P0 and P1.

[0021] According to an embodiment of the present invention, the node moving slice method in step S5 includes:

[0022] S 51 Based on coordinate system x 1 y 1 z 1 Set the slice thickness h, and determine the slice starting point. Plane P0 moves upward ;

[0023] S 52 Based on coordinate system x 0 y 0 z 0 Create slices, with slice height ranging from [value missing]. to Select the grid nodes within the slice;

[0024] S 53 According to the region division, move the grid nodes according to either Formula 1 or Formula 2 respectively;

[0025] Formula 1 is:

[0026]

[0027] Formula 2 is:

[0028]

[0029] in, This represents the maximum y-coordinate of a node within the slice plane. Let be the minimum y-coordinate of a node within the slice plane. Let θ be the minimum coordinate of a node in the z-direction within the region. c1 Let x be the coordinate system 1 y 1 z 1 The angle between the plane and P0;

[0030] According to an embodiment of the present invention, the node moving slice method in step S5 further includes:

[0031] S 54 1. Determine if all nodes within the area have been moved; if not, then... Return to step S. 52 If completed, proceed to step S6.

[0032] According to an embodiment of the present invention, step S 51Select z 1 The range of values ​​is to Nodes within.

[0033] According to an embodiment of the present invention, step S4 includes: selecting a region of grid nodes to be moved that is parallel to the coordinate system based on the coordinate system and according to the range of the z-axis and y-axis.

[0034] According to an embodiment of the present invention, step S4 further includes: based on coordinate system x 0 y 0 z 0 Based on the range of the z-axis and y-axis, select the region of grid nodes to be moved within the dashed box parallel to the coordinate system; based on the coordinate system x... 1 y 1 z 1 Based on the range of the z-axis and y-axis, select the area of ​​the grid nodes to be moved within the dashed box parallel to the coordinate system.

[0035] According to an embodiment of the present invention, step S 51 The selection of the slice thickness ensures that each slice can obtain the boundary points of the mesh nodes to be moved.

[0036] The positive and progressive effects of this invention are as follows:

[0037] This invention provides a planar mesh model size adjustment method that preserves chamfer features. Applicable to aero-engine blades, this method allows for size adjustment of the plane by moving nodes in adjacent regions using a slicing method. It offers several advantages:

[0038] 1. Enables rapid adjustment of planar dimensions without needing to modify the planar position and re-mesh in 3D modeling software;

[0039] Second, compared to the mesh topology method, the chamfer features of the planar mesh model remain unchanged after the size is adjusted, which meets the requirements of engineering drawing and processing;

[0040] Third, even when the plane is uneven or has protrusions or depressions, translation can still be achieved because the movement is within the slice.

[0041] Fourth, in the analysis of sensitivity and reliability related to planar dimensions, only one meshing is required, which improves the analysis efficiency. Attached Figure Description

[0042] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0043] Figure 1This is a schematic diagram of the planar adjustment area.

[0044] Figure 2 This is a flowchart illustrating the method for adjusting the size of a planar mesh model while maintaining chamfer features according to the present invention.

[0045] Figure 3 This is a schematic diagram of the planar mesh model size adjustment method using the slicing method in the planar mesh model size adjustment method that maintains the chamfer feature of the present invention.

[0046] Figure 4 This is a schematic diagram of the node distribution within a slice in region I of the planar mesh model size adjustment method that maintains the chamfer feature of the present invention.

[0047] Figure 5 This is a schematic diagram of the node distribution within a slice in region II of the planar mesh model size adjustment method that maintains the chamfer feature according to the present invention.

[0048] Figure 6a This is a schematic diagram illustrating the translation of a node in a traditional planar mesh along a certain direction.

[0049] Figure 6b This is a schematic diagram illustrating the scaling of traditional planar mesh node movement methods along the normal direction.

[0050] Figure 7a This is a schematic diagram of the geometric model of the original elliptical hole mesh model.

[0051] Figure 7b This is a schematic diagram of the original elliptical hole mesh model.

[0052] Figure 8a This is a schematic diagram illustrating the coordinate system establishment and region division, and the extraction of the region of the mesh node to be moved, in the planar mesh model size adjustment method that maintains the chamfer feature of the present invention.

[0053] Figure 8b This is a schematic diagram of the coordinate system establishment and region division in the planar mesh model size adjustment method that maintains the chamfer feature of the present invention, showing the mesh node to be moved.

[0054] Figure 9a This is a comparative schematic diagram of the elliptical hole mesh model before deformation in the planar mesh model size adjustment method for maintaining chamfer features according to the present invention.

[0055] Figure 9b This is a comparative schematic diagram of the deformed elliptical hole mesh model in the planar mesh model size adjustment method that maintains the chamfer feature of the present invention. Detailed Implementation

[0056] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0057] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0058] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0059] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0060] like Figures 2 to 5 As shown, this invention discloses a method for adjusting the size of a planar mesh model while maintaining chamfer features, which includes the following steps:

[0061] Step S1: Input the planar mesh model, such as... Figure 7a and Figure 7b As shown. The target adjustment plane is the area indicated by the arrow in the diagram, where the arc-shaped portion represents a depression on the plane. Because Figure 7a and Figure 7b The model is only for illustrative purposes, so it is relatively simple. This method is still effective for other planar mesh models.

[0062] Step S2: Extract the planar information of two adjacent planes P1 and P2 that form a chamfer with the plane P0 to be moved.

[0063] Step S3: Based on the extracted planar information, establish a coordinate system x according to the right-hand rule. 0 y 0 z 0 x 1 y 1 z 1 .

[0064] Preferably, step S3 includes: coordinate system x 0 y 0 z 0 x 1 y 1 z 1 The z-axis of each coordinate system is perpendicular to planes P0 and P1, respectively, and the y-axis of both coordinate systems is perpendicular to the line of intersection of planes P0 and P1. For example... Figure 8a As shown.

[0065] Step S4: Determine the area of ​​the grid nodes to be moved based on the established coordinate system.

[0066] Preferably, step S4 includes: selecting a region of grid nodes to be moved that is parallel to the coordinate system based on the coordinate system and according to the range of the z-axis and y-axis.

[0067] Step S4 further includes: based on coordinate system x 0 y 0 z 0 Based on the range of the z-axis and y-axis, select the region of grid nodes to be moved within the dashed box parallel to the coordinate system; based on the coordinate system x... 1 y 1 z 1 Based on the ranges of the z-axis and y-axis, select the region of the grid nodes to be moved within the dashed rectangle parallel to the coordinate system. The set of points in the intersection of the two rectangles is the region where the grid nodes to be moved are located, such as... Figure 8b As shown.

[0068] Step S5: Use the node moving slice method to move all nodes in the grid node area.

[0069] Preferably, the node moving slice method in step S5 includes:

[0070] S 51 Based on coordinate system x 1 y 1 z 1 Set the slice thickness h, and determine the slice starting point. Plane P0 moves upward .

[0071] Preferably, step S 51 Select z 1 The range of values ​​is to Nodes within.

[0072] Step S 51 The selection of the slice thickness ensures that each slice can obtain the boundary points of the mesh nodes to be moved, i.e. Figure 4 The node containing l0 (dotted line).

[0073] S 52 Based on coordinate system x 0 y 0 z 0 Create slices, with slice height ranging from [value missing]. to Select the grid nodes within the slice.

[0074] S 53 According to the region division, move the grid nodes according to either Formula 1 or Formula 2 respectively;

[0075] Formula 1 is:

[0076]

[0077] Formula 2 is:

[0078]

[0079] in, This represents the maximum y-coordinate of a node within the slice plane. Let be the minimum y-coordinate of a node within the slice plane. Let θ be the minimum coordinate of a node in the z-direction within the region. c1 Let x be the coordinate system 1 y 1 z 1 The angle between the plane and plane P0.

[0080] Preferably, the node moving slice method in step S5 further includes:

[0081] S 54 1. Determine if all nodes within the area have been moved; if not, then... Return to step S. 52 If completed, proceed to step S6.

[0082] Step S6: After updating the coordinates of all nodes to be moved, output the adjusted planar mesh model, such as... Figure 9b As shown.

[0083] Based on the description of the above method steps, the planar mesh model size adjustment method of the present invention, which maintains the chamfer feature, ensures that when the slice thickness h is appropriately selected, each slice should contain nodes belonging to the plane to be moved, and these points should be located on the boundary, such as... Figure 4 As shown in the middle l0 (dotted line).

[0084] There will also be other nodes within the slice, including l n Nodes on the (double-dotted line) boundary are designated as fixed points. That is, within the slice, the distance each node on l0 (dotted line) moves is determined by δ, where l n The movement distance of nodes on the (double-dotted line) boundary is 0, while the movement distance of other nodes is calculated by interpolation.

[0085] According to the above movement rules, node n in slice I will move according to the following formula:

[0086] Formula 1 is:

[0087]

[0088] in, This represents the maximum y-coordinate of a node within the slice plane. Let θ be the minimum y-coordinate of a node in the slice plane. c1 Let x be the coordinate system 1 y 1 z 1 The angle between the plane and plane P0. Divide by Because of the coordinate system x 1 y 1 z 1 There is an angle θ between it and plane P0. c1 .

[0089] Since the movement distance of the boundary points is known, other nodes are interpolated based on the movement distance of the boundary points. Therefore, even when there are other protrusions, depressions, or unevenness on the plane, the translation of the entire surface can still be achieved. After moving all nodes within the current slice, if the current slice is still within region I, then modify... The value of h is used to increase or decrease the thickness, and the next slice is selected until all grid nodes in region I have been moved.

[0090] For Region II, slicing is also required to obtain the coordinate information of the mesh nodes within the slices, but the rules for movement are changed. To prevent mesh distortion from preventing finite element analysis, the boundary mesh movement distance for Region II should be 0, and the movement distance of the connection point between the chamfer and plane P2 should be maximized. Assume the slice node distribution within Region II is as follows... Figure 5 As shown.

[0091] Among them l k (The dotted line) represents the nodes on the line connecting the chamfer and plane P2. The nodes on this line have the largest movement distance. The movement distances of other nodes are calculated by interpolation based on their positional relationship with the nodes on l0 (the dotted line). The formula for the movement of grid nodes within region II is as follows:

[0092] Formula 2 is:

[0093]

[0094] in, This represents the maximum y-coordinate of a node within the slice plane. Let be the minimum y-coordinate of a node within the slice plane. Let θ be the minimum coordinate of a node in the z-direction within the region. c1 Let x be the coordinate system 1 y 1 z 1 The angle between the plane and plane P0.

[0095] By calculating the node movement distance using the above formula, the goal of achieving zero movement on the boundary and maximizing the movement of the chamfer and the intersection line of the plane can be achieved.

[0096] like Figure 6a and 6b As shown, traditional mesh topology methods calculate the normal direction of surface nodes and then move them a fixed distance along that direction, which alters the chamfer radius. Alternatively, they directly move nodes near the planar neighborhood along the normal direction, causing the chamfer feature to fail. These traditional methods can move planar mesh nodes but lose the chamfer feature, which is highly detrimental to subsequent product design and manufacturing.

[0097] Compared to traditional mesh topology methods, this application is suitable for aero-engine blades, and its method has the following characteristics:

[0098] 1. Planar mesh nodes can be moved while the chamfer radius remains unchanged;

[0099] Second, the size of the planar mesh model can be directly adjusted, which can greatly reduce the workload of mesh re-division in analysis processes such as sensitivity analysis for models with complex configurations like blades.

[0100] Third, to move mesh nodes using the slicing method, translation can still be achieved even when the plane is uneven or has other protrusions, depressions, or other shapes.

[0101] This invention presents a planar mesh model size adjustment method that preserves chamfer features. This mesh-based planar size adjustment method adjusts the planar size by moving mesh nodes. It maintains the chamfer features at both ends of the plane after adjustment, avoiding the inefficiency caused by re-meshing. This allows for finite element analysis such as blade life assessment and reliability calculations to require only one mesh generation, significantly improving blade design efficiency.

[0102] In summary, the planar mesh model size adjustment method of the present invention, which preserves the chamfer features, can adjust the size of the plane by moving nodes in adjacent regions of the plane using a slicing method, and has the following advantages:

[0103] 1. Enables rapid adjustment of planar dimensions without needing to modify the planar position and re-mesh in 3D modeling software;

[0104] Second, compared to the mesh topology method, the chamfer features of the planar mesh model remain unchanged after the size is adjusted, which meets the requirements of engineering drawing and processing;

[0105] Third, even when the plane is uneven or has protrusions or depressions, translation can still be achieved because the movement is within the slice.

[0106] Fourth, in the analysis of sensitivity and reliability related to planar dimensions, only one meshing is required, which improves the analysis efficiency.

[0107] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for adjusting the size of a planar mesh model while preserving chamfer features, characterized in that, The method for adjusting the size of the planar mesh model includes the following steps: S1. Input planar mesh model; S2. Extract the planar information of two adjacent planes P1 and P2 that form a chamfer with the plane P0 to be moved; S3. Based on the extracted planar information, establish a coordinate system x according to the right-hand rule. 0 y 0 z 0 x 1 y 1 z 1 ; S4. Determine the area of ​​the grid nodes to be moved based on the established coordinate system; S5. Using the node-moving slicing method, all nodes are moved within the grid node region; The node moving slice method in step S5 includes: S 51 Based on coordinate system x 1 y 1 z 1 Set the slice thickness h, and determine the slice starting point. Plane P0 moves upward ; S 52 Based on coordinate system x 0 y 0 z 0 Create slices, with slice height ranging from [value missing]. to Select the grid nodes within the slice; S 53 According to the region division, move the grid nodes according to either Formula 1 or Formula 2 respectively; Formula 1 is: Formula 2 is: in, This represents the maximum y-coordinate of a node within the slice plane. Let be the minimum y-coordinate of a node within the slice plane. Let θ be the minimum coordinate of a node in the z-direction within the region. c1 Let x be the coordinate system 1 y 1 z 1 The angle between the plane and P0; S6. After updating the coordinates of all nodes to be moved, output the adjusted planar mesh model.

2. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 1, characterized in that, Step S3 includes: coordinate system x 0 y 0 z 0 x 1 y 1 z 1 The z-axis of each coordinate system is perpendicular to planes P0 and P1, respectively, and the y-axis of both coordinate systems is perpendicular to the line of intersection of planes P0 and P1.

3. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 1, characterized in that, The node moving slice method in step S5 also includes: S 54 1. Determine if all nodes within the area have been moved; if not, then... Return to step S. 52 If completed, proceed to step S6.

4. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 1, characterized in that, Step S 51 Select z 1 The range of values ​​is to Nodes within.

5. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 1, characterized in that, Step S4 includes: selecting a region of grid nodes to be moved that is parallel to the coordinate system based on the coordinate system and the range of the z-axis and y-axis.

6. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 5, characterized in that, Step S4 further includes: based on coordinate system x 0 y 0 z 0 Based on the range of the z-axis and y-axis, select the region of grid nodes to be moved within the dashed box parallel to the coordinate system; based on the coordinate system x... 1 y 1 z 1 Based on the range of the z-axis and y-axis, select the area of ​​the grid nodes to be moved within the dashed box parallel to the coordinate system.

7. The method for adjusting the size of a planar mesh model while maintaining chamfer features as described in claim 1, characterized in that, Step S 51 The selection of the slice thickness ensures that each slice can obtain the boundary points of the mesh nodes to be moved.

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