A method for parametric determination of a unit cell structure

Abstract

The application discloses a parameterization determination method of a unit cell structure, and is characterized in that: firstly, one or more scalar fields which can represent structural characteristics are solved in a design domain by user input or a finite element method; then, a periodic mapping function is introduced to establish a mapping relationship between the scalar fields and the structural characteristics, that is, all the solutions satisfying are solved in the design domain to complete extraction of the structural characteristics hidden in the scalar fields; and then, parameterization adjustment of the structural characteristics is realized by adjusting parameters contained in the mapping function. The application effectively overcomes the challenge brought by a large number of iterative interactions relying on artificial experience in traditional structural design, and has good universality.

Description

Technical Field

[0001] This invention relates to the field of computer-aided design (CAX) technology, and in particular to a method for rapidly implementing parametric design of cell structure features according to user needs, specifically a method for parametric determination of cell structure. Background Technology

[0002] In the aerospace field, every kilogram of weight reduction brings significant economic benefits. Structural lightweighting is a crucial means of achieving lightweight design. The main method of structural lightweighting is to extract and design the cell structure from the field characterizing the structural features, thereby achieving the effect of weight reduction. Therefore, an effective method for rapidly extracting the cell structure from the field characterizing the structural features according to actual needs can greatly contribute to the advancement of intelligent manufacturing.

[0003] Traditional unit cell structure design is based on the homogenization method. The core idea of ​​the homogenization method is to discretize the structure and then determine the existence of a unit cell based on its parameters. However, during the design process, units with intermediate parameter variables are prone to appear, leading to a lack of manufacturability in the final unit cell structure. Furthermore, after obtaining the unit cell structure, it is difficult to perform parameterized adjustments to the optimization results. Currently, some researchers have proposed a parameterized design method for unit cells, but this method is only applicable to simple loading conditions, such as a three-point bending beam. For complex loading conditions, the presence of singularities makes parameterized design of the unit cell structure difficult. Summary of the Invention

[0004] The purpose of this invention is to address the problems of existing unit cell structure design methods, such as difficulty in rapid iterative design when materials and processes change, low structural accuracy, low structure extraction efficiency, and difficulty in designing unit cells under complex loading conditions. This invention provides a parameterized method for determining unit cells. Users can input a scalar field representing structural features, extract the unit cell structure features using a mapping function, and then construct parameters using the mapping function to achieve parameterized design of the unit cell structure, thus meeting user needs. This method utilizes a periodic mapping function to establish a mapping relationship between the field representing structural features and the unit cell structure. Users can then adjust the relevant parameters of the mapping function according to their needs to achieve parameterized design of the unit cell structure. The unit cell structure feature extraction method proposed in this invention greatly enriches the design methods for unit cells under complex loading conditions, enabling parameterized design of unit cells. This makes rapid iterative design of structures possible when materials and processes change.

[0005] The technical solution of this invention is:

[0006] A method for parameterizing and determining a unit cell structure, characterized in that: firstly, the parameterization is performed in the design domain by user input or through the finite element method. Solve for one or more scalar fields that can characterize the structural features. Then, a periodic mapping function is introduced. Establish a mapping relationship between scalar fields and structural features, that is... Solve for all satisfying conditions within the design domain. of The implicit structural features in the scalar field are extracted; then, the parameterization of the structural features is achieved by adjusting the parameters contained in the mapping function.

[0007] The specific steps are as follows:

[0008] First, the design domain is determined by user input or through the finite element method. Solve for one or more scalar fields that can characterize the structural features.

[0009] Second, introduce mapping functions. Establish a mapping relationship between scalar fields and unit cell structure characteristics, i.e. This allows for the extraction of the cell structure features implicit in the scalar field.

[0010] Third, solve for all satisfying conditions within the design domain. of Complete the extraction of the implicit structural features in the scalar field.

[0011] Finally, if multiple scalar field characteristics are introduced to represent the structure, then the field values ​​after mapping using the mapping function will be affected. Linear superposition is performed. By using the parameters constructed by the mapping function to adjust the form of the mapping function, the parameterized adjustment of structural features can be achieved to meet the requirements under different material and process conditions.

[0012] The scalar field characterizing the features of the unit cell structure It is a scalar characterization of the distribution and variation of vectors at each point in the structure. Vectors at each point in the structure include, but are not limited to, the principal stress components and wave propagation direction at each point in the structure.

[0013] The mapping function It is a periodic function, exhibiting periodicity locally and globally over its domain r. This includes, but is not limited to, the sine function, the cosine function, and periodic composite functions constructed from these two functions, such as... Figure 1 As shown in (a), two different mapping functions were constructed, both of which can achieve the extraction of structural features, such as... Figure 1 (b) Figure 1 As shown in (c).

[0014] The parameters constructed using the mapping function, including but not limited to the period, phase, and amplitude of the mapping function, can be freely selected and set by the user according to their needs.

[0015] The above describes solving for all conditions within the design domain that satisfy... of This means that all points in the design domain with mapping values ​​greater than 0 after mapping are considered as areas with material distribution in the design domain, and points with values ​​less than 0 are considered as areas without material distribution in the design domain, i.e., holes.

[0016] The field value after mapping using the mapping function is described above. Linear superposition refers to directly superimposing the field values. Perform linear superposition, where i represents the number of scalar fields introduced to characterize the structural features.

[0017] The beneficial effects of this invention are:

[0018] This invention enables parameterized adjustment of the designed unit cell structure according to user needs, thereby meeting subsequent design and manufacturing requirements. It enriches the design methods for unit cells and expands the parameterized design methods for unit cells under complex loading conditions. Furthermore, the parameterized design method for unit cells based on mapping functions is simple and efficient, significantly shortening the design time compared to traditional unit cell design methods. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of some of the adjustment factors described in this invention.

[0020] Figure 2 (a) is a schematic diagram of the adjusted structure in Embodiment 1 of the present invention.

[0021] Figure 2 (b) is a schematic diagram of a local area of ​​the result to be adjusted in Embodiment 1 of the present invention.

[0022] Figure 2 (c) is a schematic diagram of a local area of ​​the adjusted structure in Embodiment 1 of the present invention.

[0023] Figure 2 (d) is a schematic diagram of a local area of ​​the adjusted part in Embodiment 1 of the present invention.

[0024] Figure 2 (e) is a schematic diagram of the adjustment factor selected by the user in Embodiment 1 of the present invention.

[0025] Figure 3 (a) is a schematic diagram of the wing loading situation in an embodiment of the present invention.

[0026] Figure 3(b) is the scalar field of the tensile stress components of the wing in this embodiment of the invention. Schematic diagram.

[0027] Figure 3 (d) is the scalar field of the wing compressive stress components in this embodiment of the invention. Schematic diagram.

[0028] Figure 3 (c) Figure 3 (e) is a schematic diagram of the cell structure features under the influence of the respective stress components extracted using the mapping function.

[0029] Figure 3 (f) is the mapped field value. and A schematic diagram of the superimposed results.

[0030] Figure 3 (g) is a schematic diagram of the generated cell structure that meets the requirements. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1-3 As shown.

[0033] A method for parameterizing and determining a unit cell structure, the method comprising the following steps:

[0034] S1: User input can characterize the scalar field of the unit cell structure. scalar field It is a set of points representing the distribution and changes of vectors at each point in a scalar representation structure.

[0035] S2: Using mapping functions Establish a mapping relationship between scalar fields and unit cell structure characteristics, i.e. This allows for the extraction of the cell structure features implicit in the scalar field.

[0036] S3: Solve for all conditions within the design domain. of Complete the extraction of the implicit structural features in the scalar field.

[0037] S4: If multiple scalar fields are introduced to characterize the structure, then the field values ​​after mapping using the mapping function... Linear superposition is performed. The form of the mapping function is adjusted using parameters constructed from the mapping function, thereby achieving parameterized adjustment of structural features to meet user needs.

[0038] Details are as follows:

[0039] Example 1: Design of a three-point curved beam cell structure.

[0040] User requirements: Given the loading conditions of a three-point bending beam, a lightweight design for the three-point bending beam needs to be completed, that is, the internal cell structure of the three-point bending beam needs to be calculated to achieve the purpose of lightweighting.

[0041] To demonstrate the effectiveness and universality of the method described in this invention, the following were selected: Figure 2 (a) shows a three-point curved beam structure. User input can characterize the scalar field of the unit cell structure. This includes the scalar field of tensile stress components. like Figure 2 (b) shows the scalar field of the compressive stress components. like Figure 2 As shown in (d), the cell structure features under the influence of their respective stress components are extracted using mapping functions, as follows: Figure 2 (c) Figure 2 As shown in (e), since two scalar fields influenced by tensile and compressive stresses are introduced to characterize the structure, the values ​​of these two mapped fields are directly... and Superimpose as follows Figure 2 As shown in (f), if the material properties change, the given parameters can be adjusted to change the material width of the produced unit cell structure, such as... Figure 2 As shown in (g), to meet the requirements.

[0042] Example 2: Airplane wing cell structure design.

[0043] User requirements: Given the wing's loading conditions, a lightweight design for the wing needs to be completed, which means calculating the internal cell structure of the wing to achieve the goal of lightweighting.

[0044] This example uses the following... Figure 3 Solving for the wing structure under the loading condition shown in (a), where the upper half of the wing experiences a greater uniformly distributed load than the lower half. The user input can be a scalar field characterizing the cellular structure. This includes the scalar field of tensile stress components. like Figure 3 (b) shows the scalar field of the compressive stress components. like Figure 3 As shown in (d), the cell structure features under the influence of their respective stress components are extracted using mapping functions, as follows: Figure 3 (c) Figure 3 As shown in (e), since two scalar fields influenced by tensile and compressive stresses are introduced to characterize the structure, the values ​​of these two mapped fields are directly... and Superimpose as follows Figure 3As shown in (f), finally, based on the changing process conditions, the given parameters are adjusted to generate a unit cell structure that meets the requirements, as shown in [example]. Figure 3 As shown in (g).

[0045] The present invention provides a parameterized design method for unit cell structures, which innovatively realizes the parameterized design of unit cell structures within the target structure based on user requirements. The method is simple, effective, and universal.

[0046] The parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method for parameterizing and determining a unit cell structure, characterized in that: First, the design domain is determined by user input or through the finite element method. Solve for one or more scalar fields that can characterize the structural features. Then, a periodic mapping function is introduced. Establish a mapping relationship between scalar fields and structural features, that is... Solve for all conditions within the design domain that satisfy the following conditions. of The process involves extracting the implicit structural features from the scalar field; then, by adjusting the parameters contained in the mapping function, the structural features are parameterized; the periodic mapping function... It can be locally periodic and globally periodic over its domain r; local periodicity refers to the mapping function... The function graph has peaks and troughs, which allows for the differentiation of pores and material distribution in the unit cell structure; global periodicity means that the mapping function is periodic on the domain r, and this can be achieved by adjusting the mapping function. The period and frequency parameters enable parameterized adjustment of the cell structure; the scalar field characterizing the structural features refers to the scalar field that characterizes the vector features obtained by calculating and solving the principal stress direction or wave propagation direction corresponding to the target structure to be optimized; specifically, it is obtained by direct input by the user or by solving it using finite element software after specifying boundary conditions, and the scalar field value is characterized by each discrete point inside the structure.

2. The method according to claim 1, characterized in that: The aforementioned use of mapping functions Extracting the implicit structural features from a scalar field means solving for inequalities. All of them The system can extract structural features under a single scalar field, and integrate structural features under different scalar fields by superimposing multiple mapping functions, thereby extracting structural features under given boundary conditions. The structural features can refer to the material distribution in the structure.

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