A bionic mesh structure based on the micromorphology of collagen fiber tissue

Abstract

The present invention provides a bionic reticular structure based on the micromorphology of collagen fiber tissue, which belongs to the field of bionic structure design. The bionic reticular structure is formed by a spatial array of microscopic unit cells. The basic unit cell structure is realized by connecting the center points of the opposite faces of the cubic crystal system along the three crystal axis directions of the cubic crystal system through a microstructure that imitates the shape of collagen fiber tissue. The microstructure that imitates the shape of collagen fibers in the unit cell structure can be regarded as collagen fiber bundles with different curling morphologies and thicknesses. While the three collagen fiber bundles intersect and penetrate each other, their curling morphologies and thicknesses remain independent of each other. In the present invention, the macroscopic functional structure composed of the microscopic unit cell structure, the bionic reticular structure, can not only withstand large elastic deformation, but also flexibly adjust the stress-strain curve while providing a "J"-shaped stress-strain mechanical response, and has the unique mechanical properties of a negative Poisson's ratio effect within a certain range.

Description

Technical Field

[0001] The invention relates to the field of bionic structure design, in particular to a bionic reticular structure based on collagen fiber tissue micromorphology. Background Art

[0002] Biological structures usually have unique mechanical properties, and researchers often draw inspiration from them to design high-performance structures. Different biological structures have different mechanical properties. According to application requirements, we can learn from biological structures with corresponding functions, analyze their mechanisms of action, and design them according to their principles to obtain structures with similar functions. For example, in order to meet the requirements of both strength and toughness for mechanical structures, scholars used the cross-layered characteristics of the tough queen conch to prepare corresponding metamaterials; in order to design a mechanical structure with both high energy absorption and strong pressure resistance, scholars borrowed the characteristics of the layered cell structure of the thousand-eyed bodhi.

[0003] Mechanical metamaterials refer to a class of artificial structures with unique mechanical properties, showing strength and stiffness that are superior to traditional structures. Their different mechanical properties mainly come from the designed unit cell structure and the array stacking of countless unit cells, so the unit cell is called a periodic representative unit. Through the design of the unit cell, mechanical properties such as "negative Poisson's ratio" and "high specific stiffness" can be obtained. This mechanical property mainly comes from the unique design of the structure, not from the inherent properties of the material used.

[0004] The impact of high-intensity sports on human tendons and ligaments cannot be ignored. In my country, the number of people suffering from ligament injuries reaches one million each year, and surgical reconstruction is the main treatment method. The mechanical properties of artificial tendons or ligaments currently used in the commercial industry are not optimistic. Existing solutions focus on the preparation of applicable materials, but there is little research on the multi-level structure itself. Solutions involving multi-level characteristics are usually woven structures, and the manufacturing process is relatively complicated.

[0005] Collagen fibers in the human body have good mechanical properties when subjected to tensile loads, which is due to their multi-level structure and morphological characteristics. The triple helix structure of collagen molecules at the nanoscale, the cross-linking of collagen fibrils at the mesoscale, and the bundled collection and reticular distribution of collagen fibers at the microscale all lead to good tensile properties of tissues such as tendons and ligaments at the macroscale. Biological tissues such as collagen can provide a "J"-shaped stress-strain response because their microstructures show bending characteristics. When subjected to external tension, the deformation mode presents a transition from bending to straightening, which enables the tissue to withstand tensile deformation to a great extent and achieve the possibility of large deformation. The bundled collection and reticular distribution of collagen fibers are also conducive to the uniform distribution of stress. Drawing on the above characteristics of collagen fiber tissue is conducive to the design of structures with good tensile properties. Summary of the invention

[0006] In view of the fact that there are few artificial tendon or ligament solutions and the manufacturing is complicated, the present invention draws on the morphological characteristics and reticular distribution characteristics of collagen fibers to achieve a structure with good tensile performance, and proposes a bionic reticular structure that can not only withstand large elastic deformation, but also flexibly adjust the stress-strain curve while providing a "J"-shaped stress-strain mechanical response, and has unique mechanical properties with negative Poisson's ratio effect within a certain range. This structure belongs to the scope of mechanical metamaterials, and the mechanical properties can be flexibly adjusted by changing the geometric parameters of the microscopic unit cell and the mutual combination of the two-dimensional array network.

[0007] To achieve the above-mentioned invention object, the technical solution provided by the present invention is as follows: a bionic reticular structure based on the micromorphology of collagen fiber tissue, characterized in that it is formed by unit cells through a spatial array;

[0008] The unit cell structure is realized by connecting the center points of opposite faces of the cubic crystal system along the three crystal axis directions of the cubic crystal system through a microstructure imitating the shape of collagen fiber tissue;

[0009] The curling morphology of the microstructure that mimics the shape of collagen fiber tissue is controlled by the centerline shape, and its centerline equation is:

[0010]

[0011] Among them, H represents the curl amplitude, L represents the period length, χ represents the waviness, and ω represents the number of inflection points.

[0012] Furthermore, the microstructures in the unit cell structure that mimic the shape of collagen fibers can be regarded as collagen fiber bundles with different curling morphologies and thicknesses. While the three collagen fiber bundles intersect and penetrate each other, their curling morphologies and thicknesses remain independent of each other.

[0013] Furthermore, the bionic mesh structure can be applied to the design of artificial tendons, ligaments, etc. that require good tensile properties.

[0014] Furthermore, the bionic structure design method includes the following:

[0015] S1, a regular hexahedron that meets the requirements of the cubic crystal system, whose unit cell constant is set to the period length of the microstructure of the shape of the collagen fiber tissue along the crystal axis direction;

[0016] S2, constructing three intersecting unit cell structures of microstructures imitating the shape of collagen fiber tissue along the crystal axis direction of the cubic crystal system;

[0017] S3. The curling morphology of the microstructure imitating the shape of collagen fiber tissue is controlled by the centerline shape, and its centerline equation is:

[0018]

[0019] Among them, H represents the curl amplitude, L represents the period length; χ represents the waviness; ω represents the number of inflection points;

[0020] S4, the cross section of the microstructure imitating the shape of collagen fiber tissue is a circular cross section, and the thickness of the microstructure is controlled by the diameter d of the circular cross section;

[0021] S5, periodically arranging the three-dimensional unit cells along the three crystal axis directions of the regular hexahedron to form a size-controllable bionic network structure;

[0022] Furthermore, the unit cell in step S2 can be first arranged in a plane, and another unit cell is designed to be arranged in the same plane and then spliced ​​with the former. The microstructure in the unit cell used for splicing is required to have the same morphology and thickness, while the other two microstructures are not required.

[0023] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0024] 1. Different from the traditional structure, this structure presents a negative Poisson's ratio effect within a certain range. When subjected to axial tensile loading, the lateral dimension becomes thicker and the structure becomes more stable.

[0025] 2. The overall mechanical properties can be directly controlled by designing the unit cell geometric parameters, and the combination and splicing of unit cell planar arrays can directly realize diverse structural modeling, which is flexible and simpler than the current weaving scheme.

[0026] 3. It can withstand large elastic deformation, realize nonlinear stress-strain relationship, and is less likely to reach the damage limit stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a flow chart for modeling the bionic mesh structure in the present invention.

[0029] Figure 2 It is a schematic diagram of the three-dimensional unit cell structure, the planar network structure, and the bionic network structure in the present invention.

[0030] Figure 3 It is a schematic diagram of two different unit cell planar arrays spliced ​​together in the present invention.

[0031] Figure 4It is the stress-strain curve of the finite element analysis result of the bionic mesh structure in the present invention and the front view comparison diagram before and after deformation. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0034] This embodiment provides a bionic mesh structure based on the micromorphology of collagen fiber tissue.

[0035] like Figure 1 As shown, the bionic mesh structure is formed by microscopic unit cells arranged in space;

[0036] The unit cell structure is realized by connecting the center points of opposite faces of the cubic crystal system along the three crystal axes of the cubic crystal system with microstructures imitating the shape of collagen fiber tissue;

[0037] The structural design method comprises the following steps:

[0038] S1. A regular hexahedron that meets the requirements of the cubic system, whose unit cell constant is set to the period length of the microstructure of the shape of the collagen fiber tissue along the crystal axis direction. In this embodiment, the period length L is selected to be 10 mm.

[0039] S2. Construct three intersecting unit cell structures of microstructures imitating the shape of collagen fiber tissue along the crystal axis direction of the cubic crystal system.

[0040] S3. The curling morphology of the microstructure imitating the shape of collagen fiber tissue is controlled by the centerline shape, and its centerline equation is:

[0041]

[0042] In this example, H = 2 mm, χ = 0.2 mm, ω = 4;

[0043] S4. The cross section of the microstructure that mimics the shape of collagen fiber tissue is a circular cross section, and the thickness of the microstructure is controlled by the diameter d of the circular cross section. In this embodiment, d is selected as 0.5 mm. The microscopic unit cell constructed by the above parameters is as follows: Figure 2 (a) shown.

[0044] S6. Arrange the three-dimensional unit cells periodically along the three crystal axes of the regular hexahedron to form a size of (30*30*30) mm. 3 The bionic mesh structure. Figure 2 (c) as shown.

[0045] The unit cells in step S2 can first be arrayed in a vertical plane, such as Figure 2 (b) As shown. Another unit cell can be designed to be arrayed in the same plane and then spliced ​​with the former. The microstructures used for splicing in the two unit cells are required to have the same morphology and thickness, while the other two microstructures are not required. In this embodiment, the cross-sectional diameter of the two microstructures of the other unit cell is 0.8 mm.

[0046] The structure after splicing two unit cells is as follows Figure 3 shown.

[0047] The stress-strain curve of the finite element analysis results of the bionic mesh structure in the actual design and the front view comparison diagram before and after deformation are shown in the figure. Figure 4 shown.

[0048] The bionic mesh structure can be applied to the design of artificial tendons, ligaments, etc., which require good tensile properties.

[0049] There are a few points to note:

[0050] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention, and other structures may refer to the general design.

[0051] (2) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0052] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A bionic reticular structure based on the micromorphology of collagen fiber tissue, characterized in that: It is formed by unit cells through spatial array; The unit cell structure is realized by connecting the center points of opposite faces of the cubic crystal system along the three crystal axis directions of the cubic crystal system through microstructures imitating the shape of collagen fiber tissue; the unit cell can be arranged in a plane first, and another unit cell is designed to be arranged in the same plane and then spliced ​​with the former, and the microstructure used for splicing in the unit cell is required to have the same morphology and thickness, while the other two microstructures are not required; The curling morphology of the microstructure that mimics the shape of collagen fiber tissue is controlled by the centerline shape, and its centerline equation is: Wherein, H represents the curl amplitude, L represents the unit cell constant, which is set as the period length of the microstructure of the shape of the collagen fiber organization along the crystal axis; χ represents the waviness; ω represents the number of inflection points; The microstructures in the unit cell structure that mimic the shape of collagen fibers are regarded as collagen fiber bundles with different curling morphologies and thicknesses. While the three collagen fiber bundles intersect and penetrate each other, their curling morphologies and thicknesses remain independent of each other.

2. The bionic reticular structure based on collagen fiber tissue micromorphology according to claim 1, characterized in that: The bionic mesh structure can be applied to the design of artificial tendons, ligaments and other parts requiring good tensile properties.

3. The bionic reticular structure based on collagen fiber tissue micromorphology according to claim 1, characterized in that: The bionic structure design method comprises the following steps: S1, a regular hexahedron that meets the requirements of the cubic crystal system, whose unit cell constant is set to the period length of the microstructure of the shape of the collagen fiber tissue along the crystal axis direction; S2, constructing three intersecting unit cell structures of microstructures imitating the shape of collagen fiber tissue along the crystal axis direction of the cubic crystal system; S3. The curling morphology of the microstructure mimicking the shape of collagen fiber tissue is controlled by the shape of the center line, where The equation of the centerline is: Among them, H represents the curl amplitude, L represents the period length; χ represents the waviness; ω represents the number of inflection points; S4, the cross section of the microstructure imitating the shape of collagen fiber tissue is a circular cross section, and the thickness of the microstructure is controlled by the diameter d of the circular cross section; S5. The three-dimensional unit cells are periodically arranged along the three crystal axis directions of the regular hexahedron to form a size-controllable bionic network structure.

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