Design method of shoe sole with imitation conch shell cross-lamella dot matrix structure

Abstract

The application relates to the field of shoemaking, in particular to a shoe sole design method of a shell-like conchoidal cross-lamella dot matrix structure; a cubic envelope space is constructed, the envelope space is equally spaced in the length direction and divided into multiple design spaces; a three-dimensional structure with the characteristics of cross-layer and interlayer connection is designed in the design space, and orientation difference is formed through interlayer rotation in the multi-layer array process, the same design is carried out on each design space, so that the shell-like conchoidal dot matrix unit cell with the characteristics of layering and structural anisotropy is constructed; and stress redistribution and crack delay are realized in the bending process of the structure, so that the fracture toughness of the structure is improved.

Description

Technical Field

[0001] This application relates to the field of footwear manufacturing, specifically to a method for designing shoe soles with a cross-layered dot matrix structure resembling a conch shell. Background Technology

[0002] The lattice structure used in current shoe midsoles is mostly designed based on regular periodic unit cells. Its structural form is relatively simple, and it mainly relies on the optimization of a single topological or geometric parameter to improve mechanical performance. Especially under bending and fracture conditions, significant stress concentration is easily generated inside the structure. Once cracks initiate, they tend to propagate rapidly, leading to sudden structural failure, which severely limits its application in high-reliability engineering structures.

[0003] Furthermore, most existing lattice structure designs for shoe soles lack hierarchical structures and orientation control mechanisms, making it difficult to achieve effective stress redistribution within the sole structure and thus failing to fully utilize the material's deformation potential and energy dissipation capacity. Although some studies have attempted to improve performance through topology optimization or the introduction of gradient structures, the overall approach remains at the level of homogeneous or simple gradient designs. Research on how to actively control crack propagation paths and delay fracture failure through structural configuration design is still relatively limited. Summary of the Invention

[0004] The purpose of this invention is to provide a shoe sole design method with a conch shell-like cross-layer lattice structure that reduces the bending and breakage of the shoe sole midsole.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for designing the topology of a 3D-printed shoe sole includes the following steps performed sequentially: S1: Construct a cubic envelope space, and divide the envelope space into multiple design spaces at equal intervals along the length direction; Using one square face of the design space as the first design face and the other face as the second design face, the first design face has a first diagonal and the second design face has a second diagonal. The first diagonal and the second diagonal are arranged perpendicular to each other. The two endpoints of the first diagonal are offset counterclockwise and clockwise along the first design face to obtain four first construction points. The two endpoints of the second diagonal are offset counterclockwise and clockwise along the second design face to obtain four second construction points. The first construction points and the second construction points are connected in sequence using support rods. The first construction points and the second construction points located on the same face are connected. The same design is performed on each design space to obtain a conch shell lattice unit cell. The simulated conch shell lattice unit cells are arranged in an array along the Y direction to obtain a Y-shaped single-layer lattice bending sample structure. The simulated conch shell lattice unit cells are arranged in an array along the X direction to obtain an X-shaped single-layer lattice bending sample structure. S2: Stack the y-type single-layer lattice bending specimen structure and / or the x-type single-layer lattice bending specimen structure layer by layer along the Z direction, as well as the mirror image of these two specimen structures. Different orientation differences are formed by the different forms of the single-layer lattice bending specimen structures between adjacent layers, thus obtaining lattice structures with different configurations. S3: A single-sided pre-fabricated notch is introduced on the lattice structure with different configurations to obtain the corresponding experimental specimen. The pre-fabricated notch is located at the midpoint of the length direction of the lattice structure and is used to induce crack initiation and propagation at the pre-fabricated notch position. S4: Perform three-point bending tests on each experimental specimen, obtain the corresponding test data, construct the corresponding finite element analysis model, and obtain the corresponding finite element calculation results; S5: Based on the experimental data and finite element calculation results of each experimental sample, perform quantitative analysis and calculation on each experimental sample, select the experimental sample with the best comparison results to fill the shoe sole, and obtain a 3D shoe sole printing scheme.

[0006] Preferably, the lattice structure constructed in step S2 includes a yxy type lattice structure, a yyy type lattice structure, and an xyx type lattice structure.

[0007] Preferably, the quantitative analysis calculation includes the stress intensity factor. and points The specific formula is as follows: ; in, This represents the ultimate load in the elastic stage. The span of the sample. The width of the sample. For the sample thickness, The length of the pre-crack. This is a characteristic coefficient related to the pre-crack length and the sample thickness. ; ; in, For elastic components, , The Poisson's ratio of the material, The elastic modulus of the material, Plastic component, , The remaining portion of the total energy absorbed by the sample during loading after deducting the elastically recoverable energy, when using During calculation, Take 1.9.

[0008] By adopting the aforementioned design scheme, the beneficial effects of the present invention are as follows: a conch shell-like lattice unit cell is constructed based on a cubic envelope space; an intralayer cross structure is formed by introducing the number of planes and offset parameters; and a multi-layer lattice structure with different orientations is constructed by interlayer rotation, so that the structure can achieve stress redistribution and delay cracking during bending, thereby improving the fracture toughness of the structure. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the cubic envelope space of the present invention; Figure 2 This is a schematic diagram of the design space of the present invention; Figure 3 This is a schematic diagram of the structure of the simulated conch shell lattice unit cell of the present invention; Figure 4 This is a schematic diagram of the Y-type single-layer lattice bending specimen structure and the X-type single-layer lattice bending specimen structure of the present invention. Figure 5 This is a schematic diagram of the yxy type lattice structure of the present invention; Figure 6 This is a schematic diagram of the bending test device and finite element model of the present invention; Figure 7 The experimental process and equivalent stress cloud diagram of the bending of the yxy type structure with cross-layered imitation conch shell; Figure 8 The experimental process and equivalent stress cloud diagram of the bending of the YYY type structure with cross-layered imitation conch shell; Figure 9 The experimental process and equivalent stress cloud diagram of the bending of the xyx type structure with cross-layered imitation conch shell; Figure 10 The experimental process and equivalent stress contour plot of the bending response of a traditional Octet lattice structure are shown. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0011] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0012] A method for designing the topology of a 3D-printed shoe sole includes the following steps performed sequentially: S1: As Figure 1 As shown, a cubic envelope space with a side length of L is constructed, and the envelope space is divided into multiple design spaces at equal intervals along the length direction.

[0013] Using one square face of the design space as the first design face and the other face as the second design face, the first design face has a first diagonal and the second design face has a second diagonal. The first and second diagonals are arranged perpendicularly to each other. The two endpoints of the first diagonal are offset counterclockwise and clockwise by mL distances along the first design face, respectively, to obtain four first construction points, such as... Figure 2 The purple dot is used to offset the two endpoints of the second diagonal along the second design surface by a distance mL counterclockwise and clockwise, respectively, to obtain four second construction points, as shown below. Figure 2 The green dots represent the first structural points connected sequentially by support rods (as shown by the purple lines in the figure), the second structural points connected sequentially (as shown by the green lines in the figure), and the first and second structural points located on the same plane connected (as shown by the blue lines in the figure). This identical design is applied to each design space to obtain a conch shell-like lattice unit cell. Figure 3 As shown.

[0014] The simulated conch shell lattice unit cells are arranged in an array along the Y direction to obtain a Y-shaped single-layer lattice bending specimen structure. The simulated conch shell lattice unit cells are then arranged in an array along the X direction to obtain an X-shaped single-layer lattice bending specimen structure. The Y-shaped and X-shaped single-layer lattice bending specimen structures are shown below. Figure 4 As shown; S2: Stack the y-type single-layer lattice bending specimen structure and / or the x-type single-layer lattice bending specimen structure layer by layer along the Z direction, as well as the mirror image of these two specimen structures, to obtain lattice structures with different configurations; in this embodiment, the constructed lattice structures include yxy type lattice structures, yyy type lattice structures, and xyx type lattice structures. Figure 5As shown, a schematic diagram of a yxy type lattice structure is given. The upper layer of the yxy type lattice structure is a y-type single-layer lattice bending sample structure, the middle layer is an x-type single-layer lattice bending sample structure, and the lower layer is a mirrored y-type single-layer lattice bending sample structure. By forming orientation differences through the different unit cell array forms between adjacent layers, a lattice structure with cross-layer characteristics is constructed.

[0015] S3: Single-sided pre-fabricated notches were introduced into lattice structures with different configurations to obtain corresponding experimental specimens. These pre-fabricated notches were located at the midpoint of the lattice structure's length and were used to induce crack initiation and propagation at the pre-set notch location. By controlling the consistency of lattice structure parameters across each layer, the overall relative density was kept constant, while the differences in interlayer configurations were utilized to achieve rigid-flexible coordinated deformation. In bending tests, these pre-fabricated notches were used to characterize the crack propagation behavior and fracture toughness of the lattice structure under bending loads.

[0016] S4: As Figure 6 As shown, a three-point bending test was performed on each experimental specimen to obtain the corresponding test data, and a corresponding finite element analysis model was constructed to obtain the corresponding finite element calculation results. In this embodiment, during the experiment, each test specimen was placed between two support rollers, and a displacement load was applied at the midpoint of its length to obtain the load-displacement response and failure characteristics of each specimen during the bending process. By controlling the loading rate and maintaining consistent boundary conditions, comparability between different test specimens was ensured. The finite element analysis model discretized each experimental specimen and assigned material constitutive relations and contact boundary conditions to simulate a three-point bending loading process. The stress distribution, deformation mode, and crack propagation trend of each experimental specimen were obtained through finite element analysis, and the experimental data were compared and verified to improve the reliability of the analysis results. The experimental and simulation methods are used to evaluate the mechanical response and fracture behavior of lattice structures under bending loads.

[0017] S5: Based on the experimental data and finite element calculation results of each experimental sample, perform quantitative analysis and calculation on each experimental sample, select the experimental sample with the best comparison results to fill the shoe sole, and obtain a 3D shoe sole printing scheme.

[0018] In this embodiment, the quantitative analysis calculation includes the stress intensity factor. and points Stress intensity factor It is a core indicator in linear elastic fracture mechanics that characterizes a material's resistance to crack propagation. It is applicable to Type I (opening) loading modes and reflects the intensity of the stress field at the crack tip under linear elastic conditions; integral As an important parameter in elastoplastic fracture mechanics, it characterizes the overall energy release near the crack tip. This parameter defines the energy required for crack propagation per unit area, and the specific formula is as follows: ; in, This represents the ultimate load in the elastic stage. The span of the sample. The width of the sample. For the sample thickness, The length of the pre-crack. This is a characteristic coefficient related to the pre-crack length and the sample thickness. ; ; in, For elastic components, , The Poisson's ratio of the material, The elastic modulus of the material, Plastic component, , The remaining portion of the total energy absorbed by the sample during loading after deducting the elastically recoverable energy, when using During calculation, Take 1.9.

[0019] To better illustrate the topological design method of the 3D printed shoe sole of this application, the applicant conducted the following experiments to demonstrate the design method.

[0020] Three sets of three-layer, single-sided notched bending specimens were prepared, including a yxy-type structure with interlayered cross-laminated layers resembling a conch shell, a yyy-type structure with no interlayer orientation difference, and an xyx-type structure with the x-type structure placed on the outside. Fracture behavior tests were conducted under the same relative density and loading conditions, and the crack initiation and propagation paths were characterized by combining the results of finite element analysis.

[0021] like Figures 7-10 As shown, the influence of cross-laminated orientation on the bending response of the structure is analyzed by comparing its deformation mode with that of the traditional Octet lattice structure. The results show that by introducing a flexible intermediate layer with high deformation capacity and good nodal connectivity, the load can be redistributed within the structure, resulting in a more uniform stress field. This fundamentally changes the mechanical behavior of traditional structures, where stress is typically concentrated below the indenter and near pre-existing cracks. This mechanism effectively alleviates stress concentration, significantly prolongs the stable deformation stage, and delays crack initiation and propagation, thereby improving the fracture toughness of the structure.

[0022] Table 1 shows the fracture properties of lattice structures with different configurations:

[0023] The results, as shown in Table 1, demonstrate that the proposed conch shell-like cross-lamellar lattice structure significantly enhances the fracture toughness of the lattice structure. This is manifested in the bending response characteristic, which delays structural fracture failure by dispersing stress concentration and altering internal stress transmission paths, as well as a significant increase in the J-integral in fracture performance. At a relative density of 22.50%, the J-integral of the yxy structure reaches 8.45 kJ / m², more than 20 times higher than the traditional Octet lattice structure and several times higher than other configurations. This performance improvement is attributed to the stress redistribution and multi-path energy dissipation mechanism introduced by the multi-layer cross-lamellar configuration in the structure.

[0024] In summary, this application introduces a conch shell-like cross-lamellar configuration to construct a three-dimensional structure with intralayer cross-lamellar and interlayer connectivity features within the lattice unit cell. During the multi-layer array process, orientation differences are formed through interlayer rotation, thereby constructing a lattice structure with layered characteristics and structural anisotropy. Through the differences in layered stiffness and structural anisotropy, stress redistribution can be achieved within the structure under load, forming a more uniform stress field. The cross-lamellar configuration can delay crack propagation at the interlayer interfaces, thus changing the traditional failure mode of rapid crack penetration.

[0025] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing the topology of a 3D-printed shoe sole, characterized in that: The steps are as follows, performed sequentially: S1: Construct a cubic envelope space, and divide the envelope space into multiple design spaces at equal intervals along the length direction; Using one square face of the design space as the first design face and the other face as the second design face, the first design face has a first diagonal and the second design face has a second diagonal. The first diagonal and the second diagonal are arranged perpendicular to each other. The two endpoints of the first diagonal are offset counterclockwise and clockwise along the first design face to obtain four first construction points. The two endpoints of the second diagonal are offset counterclockwise and clockwise along the second design face to obtain four second construction points. The first construction points and the second construction points are connected in sequence using support rods. The first construction points and the second construction points located on the same face are connected. The same design is performed on each design space to obtain a conch shell lattice unit cell. The simulated conch shell lattice unit cells are arranged in an array along the Y direction to obtain a Y-shaped single-layer lattice bending sample structure. The simulated conch shell lattice unit cells are arranged in an array along the X direction to obtain an X-shaped single-layer lattice bending sample structure. S2: Stack the y-type single-layer lattice bending specimen structure and / or the x-type single-layer lattice bending specimen structure layer by layer along the Z direction, as well as the mirror image of these two specimen structures. Different orientation differences are formed by the different forms of the single-layer lattice bending specimen structures between adjacent layers, thus obtaining lattice structures with different configurations. S3: A single-sided pre-fabricated notch is introduced on the lattice structure with different configurations to obtain the corresponding experimental specimen. The pre-fabricated notch is located at the midpoint of the length direction of the lattice structure and is used to induce crack initiation and propagation at the pre-fabricated notch position. S4: Perform three-point bending tests on each experimental specimen, obtain the corresponding test data, construct the corresponding finite element analysis model, and obtain the corresponding finite element calculation results; S5: Based on the experimental data and finite element calculation results of each experimental sample, perform quantitative analysis and calculation on each experimental sample, select the experimental sample with the best comparison results to fill the shoe sole, and obtain a 3D shoe sole printing scheme.

2. The topology design method for 3D printed shoe soles as described in claim 1, characterized in that: The lattice structures constructed in step S2 include yxy type lattice structures, yyy type lattice structures, and xyx type lattice structures.

3. The topology design method for 3D printed shoe soles as described in claim 2, characterized in that: The quantitative analysis calculation includes stress intensity factor. and points The specific formula is as follows: ； in, This represents the ultimate load in the elastic stage. The span of the sample. The width of the sample. For the sample thickness, The length of the pre-crack. This is a characteristic coefficient related to the pre-crack length and the sample thickness. ； ； in, For elastic components, , The Poisson's ratio of the material, The elastic modulus of the material, Plastic component, , The remaining portion of the total energy absorbed by the sample during loading after deducting the elastically recoverable energy, when using During calculation, Take 1.9.

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