Additive manufacturing-oriented shape follow-up honeycomb structure optimization design method and system

Abstract

The invention provides an additive manufacturing-oriented shape follow-up honeycomb structure optimization design method. The design method comprises the following steps of (1) honeycomb lattice parameterization design: carrying out honeycomb lattice design based on additive manufacturing cantilever angle constraint and powder cleaning requirements; (2) honeycomb filling design is conducted, specifically, based on additive manufacturing cantilever angle constraint and powder clearing requirements, plane cutting is conducted on a regularly-arranged honeycomb structure, and honeycomb filling layout design is achieved; (3) grid deformation intelligent modeling: mapping the plane honeycomb filling structure to a shape follow-up honeycomb filling structure by using an RBF interpolation algorithm to obtain a shape follow-up honeycomb finite element model; and (4) optimizing the design variables: constructing a target and constraint function, updating the design variables by using a global or local optimization algorithm, and obtaining an optimal conformal honeycomb configuration. According to the technical scheme, the technical problem that the honeycomb structure design cannot adapt to the complex special-shaped structure of the aircraft in the prior art can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of structural optimization design, and in particular relates to a conformal honeycomb structure optimization design method for additive manufacturing. Background Art

[0002] Honeycomb structures are increasingly being used in aerospace equipment due to their high strength and stiffness, excellent energy absorption, and thermal and acoustic insulation properties. Traditional honeycombs are mostly based on manual modeling, making it difficult to quickly evaluate and optimize honeycomb structures of varying thickness, size, and stacking configurations. Furthermore, the irregular aerodynamic shape and integrated structural design characteristics of aircraft result in the majority of their structures being irregularly shaped and curved. For these more complex, irregular structures, model construction and lightweight design become more difficult. Therefore, research on conformal honeycomb structure modeling and optimization methods is necessary, as it plays a crucial role in improving product design efficiency and lightweighting. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] According to one aspect of the present invention, a conformal honeycomb structure optimization design method for additive manufacturing is provided, the conformal honeycomb structure optimization design method for additive manufacturing comprising:

[0005] (1) Honeycomb lattice parametric design: honeycomb lattice design is carried out based on additive manufacturing overhang angle constraints and powder cleaning requirements;

[0006] (2) Honeycomb filling design: Based on the overhang angle constraint and powder cleaning requirements of additive manufacturing, the regularly arranged honeycomb structure is plane-cut to achieve honeycomb filling layout design;

[0007] (3) Intelligent modeling of mesh deformation: Using the RBF interpolation algorithm, the planar honeycomb filling structure is mapped to the conformal honeycomb filling structure to obtain the conformal honeycomb finite element model;

[0008] (4) Optimization of design variables: Construct objective and constraint functions, use global or local optimization algorithms to update design variables, and obtain the optimal conformal honeycomb configuration.

[0009] Furthermore, the honeycomb lattice parameterized design specifically includes:

[0010] Step 1.1: Based on the Abaqus modeling module, use shells to build honeycomb cells.

[0011] Step 1.2: Use Python to perform secondary development of Abaqus and control the main features of the honeycomb unit cell through parameters;

[0012] Step 1.3: Set powder cleaning holes on the vertical and diagonal reinforcements.

[0013] Furthermore, the main characteristics of the honeycomb unit cell include rib thickness, rib angle and honeycomb inscribed circle diameter.

[0014] Furthermore, the honeycomb filling design specifically includes:

[0015] Step 2.1: Use Python to perform secondary development on Abaqus to achieve regular arrangement of honeycombs and ensure that the honeycomb arrangement range is larger than the filling range;

[0016] Step 2.2: Use Python to perform secondary development on Abaqus to achieve cropping of a given plane area, retain the honeycomb structure within the area, remove the honeycomb structure outside the area, and form a plane honeycomb filling structure.

[0017] Furthermore, intelligent modeling of mesh deformation specifically includes:

[0018] Step 3.1: Define the background mesh domain and target mesh domain: Divide the surface filling area into a hexahedral mesh, which is defined as the target mesh domain. Transform the mesh nodes into a planar filling domain, which is defined as the background mesh domain, ensuring that the planar honeycomb filling structure is enclosed by the background mesh domain.

[0019] Step 3.2: Based on the RBF radial basis function proxy model, train the control point sets of the background grid domain and the target grid domain to obtain the mapping relationship between the background grid domain and the target grid domain;

[0020] Step 3.3: Use the planar honeycomb filling structure obtained in step 2.2 as input, perform mesh deformation based on the mapping relationship obtained in step 3.2, and obtain a conformal honeycomb finite element model with powder cleaning hole features.

[0021] Furthermore, with the main characteristics of the honeycomb unit cell, powder cleaning hole parameters and honeycomb arrangement translation parameters as variables, the structural stability calculation response and the static strength calculation stress at the powder cleaning hole as constraints, and the lightest mass as the goal, the design variables of the honeycomb lattice and honeycomb filling are updated using a global or local optimization algorithm.

[0022] According to another aspect of the present invention, a conformal honeycomb structure optimization design system for additive manufacturing is provided, which includes a honeycomb lattice parameterization design module, a honeycomb filling design module, a grid deformation intelligent modeling module and a design variable optimization module; the conformal honeycomb structure optimization design system for additive manufacturing adopts the conformal honeycomb structure optimization design method for additive manufacturing as described above to achieve conformal honeycomb structure optimization design.

[0023] The technical solution of the present invention provides a method and system for optimizing the design of conformal honeycomb structures for additive manufacturing. This method fully considers the additive manufacturing process in honeycomb structure design and uses a conformal honeycomb modeling method based on mesh deformation to transform complex curved surface finite element modeling problems into simple planar modeling problems. The design method of the present invention has strong engineering practicality, optimizes modeling time, and facilitates control of mesh quality. Compared with the prior art, the technical solution of the present invention can solve the technical problem that the prior art honeycomb structure design cannot adapt to the complex and special-shaped structures of aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the embodiments of the present invention, constitute a part of the specification, illustrate the embodiments of the present invention, and together with the description, explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0025] Figure 1 A schematic flow chart of a conformal honeycomb structure optimization design method for additive manufacturing provided according to a specific embodiment of the present invention is shown;

[0026] Figure 2 A schematic diagram of a honeycomb lattice structure design according to a specific embodiment of the present invention is shown;

[0027] Figure 3 A schematic diagram of a honeycomb powder cleaning hole design according to a specific embodiment of the present invention is shown;

[0028] Figure 4 A schematic diagram of a honeycomb filling design according to a specific embodiment of the present invention is shown;

[0029] Figure 5 A schematic diagram of RBF mapping grid deformation according to a specific embodiment of the present invention is shown; Figure 5 (a) is a schematic diagram of the background grid domain. Figure 5 (b) is a schematic diagram of the target grid domain. Figure 5 (c) is a schematic diagram of a plane honeycomb model. Figure 5 (d) is a schematic diagram of the conformal honeycomb model;

[0030] Figure 6 A schematic diagram of an optimized conformal honeycomb configuration provided according to a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0034] like Figure 1 As shown, according to a specific embodiment of the present invention, a conformal honeycomb structure optimization design method for additive manufacturing is provided, which includes: (1) honeycomb lattice parameter design; (2) honeycomb filling design; (3) grid deformation intelligent modeling; and (4) optimization of design variables.

[0035] This configuration provides a method for optimizing the design of conformal honeycomb structures for additive manufacturing. This method takes the additive manufacturing process into account when designing honeycomb structures. Using conformal honeycomb modeling based on mesh deformation, it transforms complex curved surface finite element modeling problems into simple planar modeling problems. This design method offers strong engineering practicality, optimizes modeling time, and facilitates control of mesh quality.

[0036] The following is a detailed introduction to each step in a logical order.

[0037] (1) Honeycomb lattice parametric design. This step is mainly based on the additive manufacturing overhang angle constraint and powder cleaning requirements to carry out honeycomb lattice design. It includes the following steps:

[0038] Step 1.1: Using the Abaqus modeling module, create a honeycomb unit cell using shells. The main characteristics of a honeycomb unit cell include rib thickness, rib angle, and honeycomb inscribed circle diameter.

[0039] Step 1.2: Perform secondary development of Abaqus through Python and control the main features of the honeycomb unit cell through parameters.

[0040] The main control measures are the thickness of the ribs, the rib angle and the diameter of the honeycomb inscribed circle. In order to ensure the molding quality, the process recommends that the angle between the honeycomb ribs and the horizontal plane be ≥45°, so as to meet the process constraints of the additive manufacturing cantilever angle. Generally, 45° is selected, and the honeycomb size is controlled by adjusting the honeycomb inscribed circle diameter.

[0041] Step 1.3: To meet the powder cleaning requirements of additive manufacturing, powder cleaning holes are set on the vertical and diagonal ribs. Abaqus is redeveloped using Python. The number and location of the powder cleaning holes are controlled by parameters. Considering process constraints, the minimum diameter of the powder cleaning holes is no less than 2 mm, and 3 mm is generally used.

[0042] (2) Honeycomb filling design. The main purpose of this step is to perform plane cutting of the regularly arranged honeycomb structure considering process constraints to achieve honeycomb filling layout design. The honeycomb lattice filling design is mainly based on the overhang angle constraints of additive manufacturing and the powder cleaning requirements. It includes the following steps:

[0043] Step 2.1: Use Python to perform secondary development on Abaqus to achieve regular arrangement of honeycombs and ensure that the honeycomb arrangement range is larger than the filling range.

[0044] Step 2.2: Use Python to perform secondary development on Abaqus to achieve cropping of a given plane area, retain the honeycomb structure within the area, remove the honeycomb structure outside the area, and form a planar honeycomb filling structure. When cropping, it is important to ensure that the angle between the honeycomb ribs and the horizontal plane is ≥45° as the printing direction to meet the overhang angle constraint of additive manufacturing.

[0045] In order to meet the powder cleaning requirements of the process, the first layer of honeycomb in the printing direction adopts a semi-honeycomb structure, that is, the vertical ribs of the honeycomb are in contact with the printing bottom surface, and the honeycomb edge shape can be controlled by translating the honeycomb arrangement.

[0046] (3) Mesh deformation intelligent modeling. This step is mainly used to map the plane honeycomb finite element model to a curved conformal finite element model, thus realizing conformal honeycomb finite element intelligent modeling. It includes the following steps:

[0047] Step 3.1: Define the background mesh domain and target mesh domain: Divide the surface filling area into a hexahedral mesh and define it as the target mesh domain; transform it into a planar filling domain through mesh nodes and define it as the background mesh domain, ensuring that the planar honeycomb filling structure is enclosed by the background mesh domain.

[0048] Step 3.2: Based on the RBF radial basis function proxy model, train the two control point sets, the background grid domain and the target grid domain, to obtain the mapping relationship between them. Specifically, the coordinate values ​​of the grid nodes in the background grid domain are used as input, and the coordinate values ​​of the grid nodes in the target grid domain are used as output. Each node contains coordinate values ​​in the x, y, and z directions. The coordinate value data is fitted based on the RBF proxy model to obtain the mapping relationship from the background grid domain to the target grid domain.

[0049] Step 3.3: Based on the above mapping relationship, a plane can be mapped into a special shape. Based on this idea, the planar honeycomb filling structure obtained in step 2.2 is used as input. The mesh is deformed using the mapping relationship obtained in step 3.2 to obtain a conformal honeycomb finite element model with powder cleaning hole features. This model can be directly applied to subsequent engineering detailed analysis and provides a model foundation for structural strength analysis.

[0050] (4) Optimize the design variables. This step is mainly used to construct the objective and constraint functions, and use global or local optimization algorithms to update the design variables to obtain the optimal configuration.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] (1) The honeycomb structure proposed in the present invention fully considers the additive manufacturing process and has strong engineering practicality. The optimized structure directly guides the structural design and provides a geometric basis for subsequent additive manufacturing.

[0053] (2) The present invention proposes to use a conformal honeycomb modeling method based on mesh deformation to convert the complex surface finite element modeling problem into a simple plane modeling problem and form a compiled program, which greatly reduces the modeling time and makes the mesh quality easier to control.

[0054] In order to have a further understanding of the present invention, the optimization design method of the conformal honeycomb structure for additive manufacturing of the present invention is described in detail below with reference to specific embodiments.

[0055] like Figures 1 to 6As shown, according to a specific embodiment of the present invention, a conformal honeycomb structure optimization design method for additive manufacturing is provided, and the method includes the following steps.

[0056] Step 1: Parametric design of honeycomb lattice. The main purpose of this step is to perform parametric design of the honeycomb lattice.

[0057] Step 1.1: Based on the Abaqus modeling module, the honeycomb unit cell is established using a shell. Its main features are the rib thickness, rib angle and honeycomb inscribed circle diameter. In order to ensure the molding quality, it is different from the traditional regular hexagonal honeycomb ( Figure 2 In this embodiment, the angle between the honeycomb ribs and the horizontal plane is 45° (as shown by the dotted line in the figure). Figure 2 (shown by the solid line in ).

[0058] Step 1.2: Abaqus is secondary developed through Python. The thickness of the vertical reinforcement is controlled by the parameter h, and the diameter of the honeycomb inscribed circle is the parameter R to control the honeycomb size.

[0059] Step 1.3: To meet the powder cleaning requirements of additive manufacturing, powder cleaning holes are set on the vertical ribs and oblique ribs. Abaqus is secondary developed through Python. The position of a vertical rib powder cleaning hole is controlled by parameter d1, and the position of an oblique rib powder cleaning hole is controlled by parameter d2. The positions of the other rib powder cleaning holes are determined symmetrically, as shown in the following example: Figure 3 shown.

[0060] Step 2: Honeycomb filling design. The main purpose of this step is to perform plane cutting of the regularly arranged honeycomb structure considering process constraints and realize honeycomb filling layout design.

[0061] Step 2.1: Use Python to perform secondary development on Abaqus to achieve regular arrangement of honeycombs and ensure that the honeycomb arrangement range is larger than the filling range.

[0062] Step 2.2: Use Python to perform secondary development on Abaqus to achieve cropping of a given plane area, retaining the honeycomb structure within the area and removing the honeycomb structure outside the area, such as Figure 4 As shown in the figure, in order to meet the powder cleaning requirements of the process, the first layer of honeycomb in the printing direction adopts a semi-honeycomb structure, that is, the vertical ribs of the honeycomb are in contact with the printing bottom surface, and the honeycomb arrangement can be shifted by adjusting the control parameter Xoffset∈(-R,R) to achieve honeycomb edge shape control.

[0063] Step 3: Mesh deformation intelligent modeling. This step is mainly used to map the planar honeycomb finite element model into a surface conformal finite element model to achieve conformal honeycomb finite element intelligent modeling.

[0064] Step 3.1: Define the background grid domain and target grid domain, such as Figure 5 As shown in (a), the surface filling area is divided into hexahedral meshes and defined as the target mesh domain; Figure 5 As shown in (b), the grid nodes are transformed into a plane filling domain, which is defined as the background grid domain, and its range is guaranteed to include the plane honeycomb filling area established in the above steps.

[0065] Step 3.2: Based on the RBF radial basis function proxy model, train the two control point sets of the background grid domain and the target grid domain to obtain the mapping relationship between the two. The coordinate values ​​of the grid nodes in the background grid domain are used as input, and the coordinate values ​​of the grid nodes in the target grid domain are used as output. Each node contains coordinate values ​​in the x, y, and z directions. Fit the coordinate value data based on the RBF proxy model to obtain the mapping relationship.

[0066] Step 3.3: Based on the above mapping relationship, the plane can be mapped into a special shape. Based on this idea, the plane honeycomb filling structure obtained in step 2.2 above is used as input, such as Figure 5 (c) Then, the mesh is deformed by the mapping relationship obtained in step 3.2 to achieve rapid modeling of conformal honeycomb filling structure. The result is shown in Figure 5 (d) shown.

[0067] Step 4: Optimize the design variables, with parameters h, R, d1, d2 and Xoffset as variables, structural stability calculation response λ, static strength calculation stress S at the powder cleaning hole as constraints, and lightest weight as the goal. Use global / local optimization algorithm to update the design variables. The optimized conformal honeycomb configuration is as follows: Figure 6 shown.

[0068] In summary, the present invention provides a method for optimizing the design of conformal honeycomb structures for additive manufacturing. This method fully considers the additive manufacturing process in honeycomb structure design. Using a conformal honeycomb modeling approach based on mesh deformation, it transforms the complex curved surface finite element modeling problem into a simple planar modeling problem. This design method has strong engineering practicality, optimizes modeling time, and facilitates control of mesh quality.

[0069] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A conformal honeycomb structure optimization design method for additive manufacturing, characterized in that: The conformal honeycomb structure optimization design method for additive manufacturing includes: (1) Honeycomb lattice parametric design: honeycomb lattice design is carried out based on additive manufacturing overhang angle constraints and powder cleaning requirements; (2) Honeycomb filling design: Based on the overhang angle constraint and powder cleaning requirements of additive manufacturing, the regularly arranged honeycomb structure is plane-cut to achieve honeycomb filling layout design; (3) Intelligent modeling of mesh deformation: Using the RBF interpolation algorithm, the planar honeycomb filling structure is mapped to the conformal honeycomb filling structure to obtain the conformal honeycomb finite element model; (4) Optimization of design variables: Construct objective and constraint functions, use global or local optimization algorithms to update design variables, and obtain the optimal conformal honeycomb configuration.

2. The method for optimizing the conformal honeycomb structure for additive manufacturing according to claim 1, wherein: Honeycomb lattice parametric design specifically includes: Step 1.1: Based on the Abaqus modeling module, use shells to build honeycomb cells. Step 1.2: Use Python to perform secondary development of Abaqus and control the main features of the honeycomb unit cell through parameters; Step 1.3: Set powder cleaning holes on the vertical and diagonal reinforcements.

3. The method for optimizing the conformal honeycomb structure for additive manufacturing according to claim 2, wherein: The main characteristics of a honeycomb cell include rib thickness, rib angle, and honeycomb inscribed circle diameter.

4. The method for optimizing the conformal honeycomb structure for additive manufacturing according to claim 1, wherein: Honeycomb filling design specifically includes: Step 2.1: Use Python to perform secondary development on Abaqus to achieve regular arrangement of honeycombs and ensure that the honeycomb arrangement range is larger than the filling range; Step 2.2: Use Python to perform secondary development on Abaqus to achieve cropping of a given plane area, retain the honeycomb structure within the area, remove the honeycomb structure outside the area, and form a plane honeycomb filling structure.

5. The method for optimizing the conformal honeycomb structure for additive manufacturing according to claim 4, wherein: Intelligent modeling of mesh deformation specifically includes: Step 3.1: Define the background mesh domain and target mesh domain: Divide the surface filling area into a hexahedral mesh, which is defined as the target mesh domain. Transform the mesh nodes into a planar filling domain, which is defined as the background mesh domain, ensuring that the planar honeycomb filling structure is enclosed by the background mesh domain. Step 3.2: Based on the RBF radial basis function proxy model, train the control point sets of the background grid domain and the target grid domain to obtain the mapping relationship between the background grid domain and the target grid domain; Step 3.3: Use the planar honeycomb filling structure obtained in step 2.2 as input, perform mesh deformation based on the mapping relationship obtained in step 3.2, and obtain a conformal honeycomb finite element model with powder cleaning hole features.

6. The method for optimizing the conformal honeycomb structure for additive manufacturing according to claim 1, wherein: Taking the main characteristics of the honeycomb unit cell, powder cleaning hole parameters and honeycomb arrangement translation parameters as variables, the structural stability calculation response and the static strength calculation stress at the powder cleaning hole as constraints, and the lightest weight as the goal, the global or local optimization algorithm is used to update the design variables of the honeycomb lattice and honeycomb filling.

7. A conformal honeycomb structure optimization design system for additive manufacturing, characterized in that: The conformal honeycomb structure optimization design system for additive manufacturing includes a honeycomb lattice parameterization design module, a honeycomb filling design module, a grid deformation intelligent modeling module, and a design variable optimization module; The conformal honeycomb structure optimization design system for additive manufacturing adopts the conformal honeycomb structure optimization design method for additive manufacturing as described in claims 1 to 6 to achieve conformal honeycomb structure optimization design.

Images