A feature-based rapid design modeling method for aircraft structural components

Abstract

The application discloses a feature-based rapid design modeling method for an aircraft structural member, which comprises the following steps: feature decomposition, feature structure analysis, feature template establishment, feature constraint creation, feature instantiation, feature surface simplification and correction, feature information extraction, generation of an assembly symmetric counter-piece and a non-complete assembly symmetric counter-piece, so that the computer can automatically create the relevant constraints between the base body and the created features by recognizing the position information of the created features and the base body, automatically generate the features by driving the CAA template program, freely modify the feature size parameters according to the user demand or increase or decrease the features on the original geometric body by Boolean operation to complete the variant design of the part, and freely extract the feature parameter information, thereby improving the freedom of the model modification of the aircraft structural member by the designer and the design efficiency of the aircraft structural member.

Description

Technical Field

[0001] This invention belongs to the field of computer-aided design, specifically relating to a feature-based rapid design and modeling method for aircraft structural components. Background Technology

[0002] Aircraft structural components are typical products produced in small batches and with a wide variety of types, which is not conducive to the accumulation and reuse of knowledge. As aircraft structural components gradually develop towards larger size, integration, and complexity, the current design of aircraft structural components is characterized by a wide variety of types, complex structures, cumbersome design, and compact overall structure. Efficient and high-quality design of aircraft structural components is an important condition for ensuring aircraft performance and development progress. In order to change the traditional design methods of aircraft structural components, parametric modeling technology is introduced to improve the design efficiency of aircraft structural components.

[0003] Current patent publications and literature show that: 1) Patent (CN202011262345.6) discloses a human-machine hybrid enhanced intelligent design method based on aircraft structural components. This method achieves the accumulation and reuse of aircraft structural component design knowledge and experience through interaction between designers and expert systems. However, this method requires a large amount of hard-to-obtain rule information and is not very practical; 2) Patent (CN202110887001.6) discloses a method based on CATIA. CAA's rapid modeling method for deformable design of aircraft structural components improves the design efficiency of aircraft structural components to some extent by modifying the parameters of existing old instances in the instance library. However, this method requires a large number of old instances that meet its deformable design requirements, and it cannot add or remove features of the parts, cannot guarantee the smooth transition of the curved surfaces of the parts after deformable design, and cannot extract feature information of the parts. 3) Patent (CN202210195576.2) discloses a human-machine hybrid enhanced aircraft structural component design method based on instance reasoning. This method improves the design efficiency of aircraft structural components by calculating the similarity between the part to be designed and the parts in the instance library, searching for the best similar part, and performing deformable design on it. However, in the process of similarity calculation, there will inevitably be cases where the similarity is very high, but each feature is different. At this time, it is still necessary to perform deformable design on all features, so the efficiency is not improved.

[0004] In summary, while existing aircraft structural component design methods have improved design efficiency to some extent, they still suffer from numerous problems, such as difficulty in knowledge acquisition, the need to store a large number of part instances in an instance library for variant design requirements, difficulty in modifying or adding / removing the dimensions of individual part features, and low design accuracy. In the process of aircraft structural component design, it is necessary to consider the ease of operation for designers, the accuracy of part design, and the freedom to modify feature parameters and add / remove features, thereby improving design efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a feature-based rapid design and modeling method for aircraft structural components, addressing the problems of long product design cycles and low product qualification rates in aircraft structural component design. The method involves decomposing the structure of a similar part into individual features, then creating feature templates from these features. The parameters of the feature templates are then modified according to the requirements of the part to be designed, thereby instantiating the feature templates. Finally, feature reconstruction and feature splicing are performed to complete the creation of the target part. Compared to traditional methods of creating parts individually, this significantly shortens the design steps and design cycle, and improves the product qualification rate.

[0006] To achieve the above-mentioned objectives, the technical solution of this application is as follows: The flowchart of this method is shown below. Figure 1 As shown.

[0007] A feature-based rapid design and modeling method for aircraft structural components, characterized by the following steps:

[0008] Step 1: Decompose the features of the aircraft structural components, perform structural analysis on the decomposed features, and establish a feature CAA program template;

[0009] Step 2: Modeling and design. When modeling, first establish the constraint relationship, then call the feature template. According to the required shape and size parameters of the designed part, input the feature parameters through the human-computer interaction interface, and drive the instantiation of the feature template through the parameters and constraint relationship.

[0010] Step 3: Perform feature reconstruction and splicing operations on the feature instances and the part base to achieve the transformation design of the part by modifying the features, thereby quickly building the part model;

[0011] Step 4: Simplify and correct the surface features of parts with complex curved surfaces to make the surface transitions of the model smooth; generate symmetrical inverse parts for parts with symmetrical features to eliminate the need for repeated modeling steps for symmetrical parts.

[0012] Step 5: Identify and extract features from the established part model to create a feature extraction library, and then perform 3D annotation on the feature models identified and extracted from the model.

[0013] Furthermore, the creation of the feature CAA program template described in step one adopts the dynamic programming modeling method, that is, using the development platform provided by CATIA software, and the dynamic programming modeling method of secondary development of CATIA software through CAA to establish typical feature template files of complex aircraft parts.

[0014] Furthermore, the aircraft structural component feature decomposition described in step one is divided according to shape, specifically into: groove features, hole features, rib features, and auxiliary features. Among them, groove features include flat-bottomed grooves, sloping-bottomed grooves, and curved-bottomed grooves; hole features include through holes and blind holes; rib features include straight-top ribs, sloping-top ribs, and open ribs; and auxiliary features include process bosses and reference surfaces.

[0015] Furthermore, in step three, when modifying the geometric parameters of all features of a part or some features of a part individually or in batches, the designer inputs the parameters to be modified through the human-computer interaction interface, and the newly input parameters are added to the feature template program. Meanwhile, the other feature parameters remain unchanged, and the original constraints of the part model are not destroyed, thus realizing the linkage of the constraints of the part model.

[0016] Furthermore, in step three, when reconstructing and stitching features, the size parameters of each feature unit need to be determined, and there must be positional and constraint relationships between the features.

[0017] Furthermore, the simplification and correction of the surface of the part model described in step four adopts the vertex deletion method in the geometric element deletion method. That is, in the triangular mesh, a vertex and its surrounding triangular facets can be considered coplanar (this can be determined by setting a threshold for the distance from the point to the plane), and the deletion of this point will not cause a change in the topology, that is, it will not affect the features of the part. So this point is deleted. At the same time, all faces connected to this vertex are deleted in the original model. Then, its neighborhood is retriangulated to fill the void caused by the deletion of this point.

[0018] Furthermore, there are two ways to modify the features to perform variant design of aircraft structural components as described in step three: 1) By modifying one or more feature size parameters, the feature size can be driven to change, thereby realizing the variant design of aircraft structural components based on changing the feature size of the parts; 2) By using Boolean operations to drive the feature template program and the part base to realize the union, intersection, and subtraction operations between the base and the features, thereby realizing the variant design of aircraft structural components based on adding or subtracting features.

[0019] Furthermore, the specific process for feature identification and extraction described in step five is as follows: First, obtain the parameterized 3D model, the current document editor, and the current document; obtain the root container and first element of the part; obtain the handle of the part; and call relevant functions to traverse the feature tree of the part, find the corresponding features, and instantiate the objects. At this time, assign the objects to the corresponding documents and initialize the documents. Then, extract all the features of the part according to the feature extraction library, and convert the CATPart type features into a CATICkeParm type feature list. Finally, perform a loop step, by browsing the feature information in the feature list and comparing it with the feature parameters in the feature extraction library, to determine whether the feature parameters in the feature list are consistent with the feature parameters in the extraction library. If they are consistent, extract the feature parameter information; if they are inconsistent, continue browsing the feature list information until the loop ends.

[0020] Furthermore, the above five steps can be used to change the size of the part's features and add or remove features. By continuing to use this method to create other target part features, multiple part features can be created or modified continuously. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following description will be made with reference to the accompanying drawings. The drawings described below are merely embodiments of the present invention and do not constitute a limitation on the present invention.

[0022] Figure 1 This is a flowchart of the feature-based rapid design and modeling method for aircraft structural components provided by the present invention;

[0023] Figure 2 This invention provides a modeling reference and main feature diagram for a typical aircraft structural component, the control surface suspension joint.

[0024] Figure 3 These are before-and-after comparison images of the modified design of a typical aircraft structural component, the control surface suspension joint, based on modified feature parameters, provided by this invention.

[0025] Figure 4 These are before-and-after comparison diagrams of the modified design of a typical aircraft structural component wing spars based on added and subtracted features, provided by this invention.

[0026] Figure 5 This is a flowchart of the feature information annotation process for aircraft structural components provided by the present invention.

[0027] The annotations in the attached figures are explained as follows:

[0028] 1. Connector lug axis; 2. Lug hole axis; 3. Connector lug center surface; 4. Support end face; 5. Upper edge line of the end face; 6. Lower wing surface mating surface; 7. Hole features; 8. Groove features; 9. Lug features; 10. Rib features; 11. Substrate. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0030] (1) Step one, as follows Figure 2 As shown, taking the control surface suspension joint as an example, this paper illustrates the specific operation process of the feature-based rapid design and modeling method for aircraft structural components. Based on the structural characteristics of the control surface suspension joint, the composition of the main features is analyzed and the corresponding position and constraint relationships are established. The control surface suspension joint uses a cuboid as the modeling base 11, and combines features such as slot 8, hole 7, rib 10, and lug 9 with the base in sequence to form an overall model. Each feature unit needs to have its dimensional parameters determined, and there must be position and constraint relationships between each feature. These position and constraint relationships constitute the modeling datum of the part, including the lug axis 1, lug hole axis 2, lug center surface 3, support end surface 4, upper edge line of the end surface 5, and lower wing surface mating surface 6. The determined modeling datum is established in advance.

[0031] (As shown in the table below, and in the order of Table 1, where Table 1 is a classification table of aircraft structural components according to shape characteristics provided by the present invention).

[0032]

[0033] (2) Step 2: Based on Step 1, open the modeling reference 11 of the created rudder suspension joint, call the feature CAA program template of the rudder suspension joint that has been created, and pick up the modeling references in sequence through the human-computer interaction interface: lug axis 1, lug axis 2, joint lug center surface 3, support end surface 4, end upper upper edge line 5, lower wing surface mating surface 6. The designer judges whether the modeling references are complete. If they are not complete, they need to be picked up again. If they are complete, proceed to the next step.

[0034] (3) Step 3: Based on Step 2, modify the feature parameters according to the design requirements and determine the main geometric parameters of each feature of the rudder suspension joint, mainly the outer radius of the lug, the inner diameter of the lug, the thickness of the lug, the width of the slot, the distance from the upper edge, and the thickness of the end face. After modifying the feature parameters, click "Start Modeling". The system automatically drives the CAA template program to complete the feature splicing operation between the rudder suspension joint feature after the feature parameters are modified and the feature of the part base through Boolean operations, creating the rudder suspension joint model after the parameter modification. This completes the variant design of the rudder suspension joint feature template based on the modified feature parameters. The comparison between the rudder suspension joint model before and after the feature parameter modification is as follows: Figure 3 As shown.

[0035] (4) Step four: If the part model needs to add or remove features according to design requirements, first establish the part model according to steps two and three, and use it as the feature modeling base 11. Then call the CAA template program for the features to be added, and repeat the operations from step one to step three to complete the variation design of the part based on adding or removing features. Taking the addition or removal of features of the wing beam model as an example, this operation is illustrated. The wing beam model base is established through the steps described in steps two and three. Then, the two features that the user needs to add, namely the single-sided boss reference hole and the stringer notch, are selected and Boolean operations are performed on the wing beam model base to add or remove them respectively, so as to obtain the wing beam model with the single-sided boss reference hole and the stringer notch features added. The comparison of the wing beam before and after adding the single-sided boss reference hole and the stringer notch features is as follows. Figure 4 As shown.

[0036] (5) The part model created through the above four steps can freely add or remove features and modify feature dimensions according to user design requirements, greatly improving the freedom of part transformation design.

[0037] (6) If the part model created through the above four steps requires 3D annotation, the system can automatically extract feature information and complete the 3D dimension annotation of the model. The feature annotation flowchart is as follows: Figure 5 As shown in the table below, the feature extraction library is in the order of Table 2, where Table 2 is the feature information extraction library for aircraft structural components provided by this invention.

[0038]

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation schemes of the present invention, and these modifications or equivalent substitutions do not depart from the spirit and scope of the present invention, and are all within the protection scope of the claims of the present invention pending approval.

Claims

1. A feature-based rapid design modeling method for aircraft structural components, characterized in that, Includes the following steps: Step 1: Decompose the features of the aircraft structural components, perform structural analysis on the decomposed features, and establish a feature CAA program template; Step 2: Modeling and design. When modeling, first establish the constraint relationship, then call the feature template. According to the required shape and size parameters of the designed part, input the feature parameters through the human-computer interaction interface, and drive the instantiation of the feature template through the parameters and constraint relationship. Step 3: Perform feature reconstruction and splicing operations on the feature instances and the part base to achieve the transformation design of the part by modifying the features, thereby quickly building the part model; Step 4: Simplify and correct the surface features of parts with complex curved surfaces to make the surface transitions of the model smooth; generate symmetrical inverse parts for parts with symmetrical features to eliminate the need for repeated modeling steps for symmetrical parts. Step 5: Identify and extract features from the established part model to create a feature extraction library, and then perform 3D annotation on the feature models identified and extracted from the model.

2. The feature-based rapid design modeling method for aircraft structural components according to claim 1, characterized in that, The creation of the feature CAA program template described in step one adopts the dynamic programming modeling method, that is, using the development platform provided by CATIA software, and using CAA to perform secondary development of CATIA software through dynamic programming modeling to establish typical feature template files for complex aircraft parts.

3. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, Aircraft structural component features are classified according to their shape, specifically into: groove features, hole features, rib features, and auxiliary features. Groove features include flat-bottomed grooves, sloping-bottomed grooves, and curved-bottomed grooves; hole features include through holes and blind holes; rib features include straight-top ribs, sloping-top ribs, and open ribs; and auxiliary features include process bosses and reference surfaces.

4. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, When reconstructing and splicing features in step three, the size parameters of each feature unit need to be determined, and there must be positional and constraint relationships between each feature.

5. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, In step three, when modifying the geometric parameters of all features of a part or some features of a part individually or in batches, the designer inputs the parameters to be modified through the human-computer interaction interface, and the newly input parameters are added to the feature template program. The other feature parameters do not change, and the original constraints of the part model are not destroyed, thus realizing the linkage of the constraints of the part model.

6. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, The simplification and correction of the surface of the part model described in step four uses the vertex deletion method in the geometric element deletion method. That is, in the triangular mesh, a vertex and its surrounding triangular facets can be considered coplanar, and the deletion of this point will not cause a change in the topology and will not affect the features of the part. So this point is deleted. At the same time, all faces connected to this vertex are deleted in the original model. Then its neighborhood is retriangulated to fill the void caused by the deletion of this point.

7. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, By modifying one or more feature dimension parameters, feature dimension changes can be driven, enabling the variant design of aircraft structural components based on changes in part feature dimensions.

8. A feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, The feature reconstruction and splicing operations described in step three use Boolean operations to drive the feature template program and the part base to achieve the union, intersection, and subtraction of the base and features, thereby realizing the variant design of aircraft structural components based on adding or subtracting features.

9. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, The specific process for feature identification and extraction described in step five is as follows: First, obtain the parameterized 3D model, the current document editor, and the current document; obtain the root container and first element of the part; obtain the handle of the part; and call relevant functions to traverse the feature tree of the part, find the corresponding features, and instantiate the objects. At this time, assign the objects to the corresponding documents and initialize the documents. Then, extract all the features of the part according to the feature extraction library, and convert the CATPart type features into a CATICkeParm type feature list. Finally, perform a loop step, by browsing the feature information in the feature list and comparing it with the feature parameters in the feature extraction library, to determine whether the feature parameters in the feature list are consistent with the feature parameters in the extraction library. If they are consistent, extract the feature parameter information; if they are inconsistent, continue browsing the feature list information until the loop ends.

10. The feature-based rapid design and modeling method for aircraft structural components according to claim 1, characterized in that, The above five steps can be used to change the size of part features and add or remove features. By continuing to use this method to create other target part features, multiple part features can be created or modified continuously.

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