A three-dimensional double-arrow negative Poisson's ratio material and its manufacturing method

Abstract

The present invention provides a three-dimensional double-arrow negative Poisson's ratio material and method, comprising: a double-arrow structural unit, wherein the double-arrow structural unit is interconnected along the x-axis, y-axis, and z-axis in three-dimensional space to form an array structure; the double-arrow structural unit comprises two arrow-shaped frame structures pointing in opposite directions, wherein the arrow-shaped frame structure comprises an upper rod, two oblique rods symmetrically connected to the ends of the upper rod, and two bottom rods connected between the two oblique rods, wherein the other ends of the two bottom rods are connected and tilted toward one side of the upper rod to form a concave structure; the two arrow-shaped frame structures pointing in opposite directions are vertically connected at the connection position of the two bottom rods. The negative Poisson's ratio effect of the present invention is superior to that of traditional negative Poisson's ratio metamaterials. The double-arrow directions of the present invention are mutually opposite and orthogonal to each other. When under pressure, the arrows at both ends are compressed, and the tail of the middle arrow shrinks toward the middle, which has a better effect. The negative Poisson's ratio effect of the structure responds faster.

Description

Technical Field

[0001] The present invention relates to the technical field of negative Poisson's ratio metamaterial energy absorption technology, and in particular to a three-dimensional double-arrow negative Poisson's ratio material and a manufacturing method thereof. Background Art

[0002] At present, production and construction are constantly developing, and the requirements for engineering technology are also increasing. The applicability of traditional mechanical materials in some fields has gradually decreased and can no longer meet the needs of people's production and life. Therefore, some materials with extraordinary mechanical properties are needed to be applied to engineering technology.

[0003] Negative Poisson's ratio metamaterials have the mechanical property of contracting when compressed and expanding when tensile. This gives them superior shear resistance, specific energy absorption, specific strength, and impact resistance compared to traditional mechanical metamaterials. Currently, negative Poisson's ratio metamaterials are widely used in vehicles, ships, aerospace, medical devices, and other fields, playing an important role.

[0004] At present, researchers have proposed some structural models of metamaterials with double-arrow negative Poisson's ratio, but there is little research on three-dimensional double-arrow negative Poisson's ratio metamaterials. Most of the existing double-arrow negative Poisson's ratio metamaterials are not lightweight enough, the negative Poisson's ratio effect is not significant enough, and the initial stress is too high and the stability is poor when subjected to impact load and pressure. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a three-dimensional double-arrow negative Poisson's ratio material and a manufacturing method thereof. Compared with previous double-arrow negative Poisson's ratio metamaterials, the present invention has a better customizable negative Poisson's ratio effect and is more lightweight. It is of great significance in improving the negative Poisson's ratio performance of materials and enhancing structural stability and universality.

[0006] The present invention provides a three-dimensional double-arrow negative Poisson's ratio material, comprising: double-arrow structural units, which are interconnected along the x-axis, y-axis, and z-axis directions in three-dimensional space to form an array structure; the double-arrow structural units include two arrow-shaped frame structures pointing in opposite directions, the arrow-shaped frame structures include an upper rod, two oblique rods symmetrically connected to the two ends of the upper rod, and two bottom rods connected between the two oblique rods, the other ends of the two bottom rods are connected and inclined toward one side of the upper rod to form a concave structure; the two arrow-shaped frame structures pointing in opposite directions are vertically connected at the connection position of the two bottom rods; the outer side of the connection position between the oblique rod and the bottom rod has a connecting section, in the x-axis and y-axis directions, two adjacent double-arrow structural units are connected to each other through the connecting section; in the z-axis direction, two adjacent double-arrow structural units are connected to each other through the upper rod.

[0007] Furthermore, the length of the bottom rod is greater than the length of the upper rod.

[0008] Furthermore, a lower rod is connected to the position where the bottom rod is connected, and the lower rod is parallel to the upper rod.

[0009] Furthermore, the length of the lower rod is equal to that of the upper rod.

[0010] Furthermore, the angle between the oblique rod and the bottom rod is an acute angle.

[0011] Furthermore, the connecting section is a square.

[0012] Furthermore, two adjacent connection sections are seamlessly connected.

[0013] The present invention provides a method for manufacturing a three-dimensional double-arrow negative Poisson's ratio material, comprising:

[0014] S1, draw a 2D sketch of the single-arrow structure on the front view datum plane;

[0015] S2, based on the 2D sketch of the single-arrow structure, offset it in two directions with equal distance, and then stretch it in two directions with equal distance to form a 3D sketch of the single-arrow structure;

[0016] S3, cut a connecting section at the connection between the oblique rod and the bottom rod to form a three-dimensional model of the upper half of the double-arrow structural unit;

[0017] S4, mirroring the three-dimensional model of the upper half of the double-arrow structural unit with a reference plane passing through the axis of the lower rod and perpendicular to the front reference plane as a mirror plane, then rotating the mirrored three-dimensional model 90° around the reference axis perpendicular to the lower rod, and combining the two parts to form a double-arrow structural unit;

[0018] S5, seamlessly connect each double-arrow structural unit in the horizontal direction through the connecting section, and seamlessly connect the upper rod of the previous double-arrow structural unit with the upper rod of the next double-arrow structural unit in the vertical direction, so as to array each double-arrow structural unit in the horizontal and vertical directions to form a three-dimensional double-arrow negative Poisson's ratio material.

[0019] Furthermore, in step S2, the bidirectional equidistant offset is performed by t / 2, and then the bidirectional stretching is performed by t / 2.

[0020] Furthermore, in step S3, the connection section is a square with a side length of t.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The three-dimensional double-arrow negative Poisson's ratio metamaterial proposed in the present invention has a negative Poisson's ratio effect that is superior to traditional negative Poisson's ratio metamaterials. The double arrows in the present invention are in opposite directions and orthogonal to each other. When compressed, the arrows at both ends are compressed, and the tail of the middle arrow contracts toward the middle, achieving a better effect. The negative Poisson's ratio effect of the structure also responds faster than traditional negative Poisson's ratio metamaterials.

[0023] 2. In the traditional three-dimensional arrow re-entrant structure, the arrows are designed in the same direction and are orthogonal to each other. This design method causes the structures to contact each other too early when loaded, and the structure enters the dense stage too early, resulting in less than ideal energy absorption effect. In the present invention, the design of a unit cell is formed by making the double arrows mutually inverse and orthogonal to each other, so as to better improve the specific energy absorption effect of the structure in a limited space.

[0024] 3. The structure of the present invention has adjustable Poisson's ratio. By changing the length ratio of the diagonal rod and the bottom rod and the angle between the two rods, the Poisson's ratio of the structure can be adjusted. At the same time, the response speed of the Poisson's ratio can also be adjusted, which is convenient for application in various scenarios.

[0025] 4. The connection of the lattice structure in the present invention is designed to be seamlessly connected through the connection section, which can improve the energy absorption effect of the structure, effectively reduce the stress concentration phenomenon, and improve the stability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of a double-arrow structural unit according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the array structure of the three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention;

[0029] Figure 3 This is a front view of a three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention;

[0030] Figure 4 A top view of a three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the two-dimensional dimensions of the double-arrow structural unit according to an embodiment of the present invention;

[0032] Figure 6Schematic diagram of the three-dimensional dimensions of the double-arrow structural unit according to an embodiment of the present invention;

[0033] Figure 7 This is a deformation process diagram of a three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention;

[0034] Figure 8 This is a force-displacement curve diagram of a three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention;

[0035] Figure 9 This is a strain-specific energy absorption curve of a three-dimensional double-arrow negative Poisson's ratio material according to an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1: Upper rod; 2: Diagonal rod; 3: Bottom rod; 4: Connecting section; 5: Lower rod. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0041] like Figure 2 As shown, the embodiment of the present invention provides a three-dimensional double-arrow negative Poisson's ratio material, including: double-arrow structural units, which are interconnected along the x-axis, y-axis, and z-axis directions in three-dimensional space to form an array structure. Figure 1 As shown, the double-arrow structural unit includes two arrow-shaped frame structures pointing in opposite directions, and the arrow-shaped frame structure includes an upper rod 1, two oblique rods 2 symmetrically connected at both ends of the upper rod 1, and two bottom rods 3 connected between the two oblique rods 2. The other ends of the two bottom rods 3 are connected and tilted toward one side of the upper rod 1 to form a concave structure. The two arrow-shaped frame structures pointing in opposite directions are vertically connected at the connection position of the two bottom rods 3. Preferably, in a specific embodiment, the position where the bottom rods 3 are connected is connected with a lower rod 5, and the lower rod 5 is parallel to the upper rod 1. The two arrow-shaped frame structures pointing in opposite directions are vertically connected through the lower rod 5. The outer side of the connection position between the oblique rod 2 and the bottom rod 3 has a connecting section 4. In the x-axis and y-axis directions, the two adjacent double-arrow structural units are connected through the connecting section 4; in the z-axis direction, the two adjacent double-arrow structural units are connected through the upper rod 1.

[0042] It should be noted that the upper rod 1, the oblique rod 2, the bottom rod 3, and the lower rod 5 in the present invention are all made of deformable and elastic materials, such as metal materials, synthetic materials, etc. The three-dimensional double-arrow negative Poisson's ratio metamaterial proposed in the present invention has a negative Poisson's ratio effect that is better than that of traditional negative Poisson's ratio metamaterials. The directions of the double arrows in the present invention are mutually opposite and orthogonal to each other. When under pressure, the arrows at both ends are compressed and the tail of the middle arrow shrinks toward the middle, which has a better effect. The negative Poisson's ratio effect response speed of the structure is also faster than that of traditional negative Poisson's ratio metamaterials. Moreover, the design of the double-arrow structural unit formed by the double arrows being mutually opposite and orthogonal to each other in the present invention can better improve the specific energy absorption effect of the structure in a limited space.

[0043] Preferably, the length of the bottom rod 3 is greater than that of the upper rod 1, the length of the lower rod 5 is equal to that of the upper rod 1, and the angle between the diagonal rod 2 and the bottom rod 3 is an acute angle. It should be noted that the length of the bottom rod 3 relative to the upper rod 1, as well as the angle between the diagonal rod 2 and the bottom rod 3 in the present invention can be adjusted according to specific needs, so that the structure of the present invention has Poisson's ratio adjustability. By changing the length ratio of the diagonal rod 2 to the bottom rod 3 and the angle between the two rods in the structure, the Poisson's ratio of the structure can be adjusted, and the response speed of the Poisson's ratio can also be adjusted, which is convenient for application in various scenarios.

[0044] In a preferred embodiment of the present invention, Figure 6 As shown, the connecting section 4 is square. Two adjacent connecting sections 4 are seamlessly connected. The seamless connection design of the connecting sections 4 can improve the energy absorption effect of the structure, effectively reduce stress concentration, and enhance the stability of the structure.

[0045] An embodiment of the present invention further provides a method for manufacturing a three-dimensional double-arrow negative Poisson's ratio material, comprising:

[0046] Step S1, draw a two-dimensional sketch of a single arrow structure on the front reference plane. Figure 5 As shown, the length of the upper rod 1 is d; the length of the inclined rod 2 is L; the length of the lower rod 5 is d; and the angle between the inclined rod 2 and the bottom rod 3 is θ.

[0047] Step S2: Based on the two-dimensional sketch of the single-arrow structure, perform bidirectional equidistant offset and bidirectional equidistant stretching to form a three-dimensional sketch of the single-arrow structure. Preferably, perform bidirectional equidistant offset by t / 2 and then bidirectional stretching by t / 2.

[0048] Step S3: Cut a connecting section 4 at the connection between the oblique rod 2 and the bottom rod 3 to form a three-dimensional model of the upper half of the double-arrow structural unit. Preferably, the connecting section 4 is a square with a side length of t.

[0049] Step S4, mirror the three-dimensional model of the upper half of the double-arrow structural unit with the reference plane passing through the axis of the lower rod and perpendicular to the front view reference plane as the mirror plane, and then rotate the mirrored three-dimensional model 90° around the reference axis perpendicular to the lower rod, and combine the two parts to form a double-arrow structural unit.

[0050] Step S5: seamlessly connect the double-arrow structural units in the horizontal direction through the connecting section 4, and seamlessly connect the upper rod 1 of the previous double-arrow structural unit with the upper rod 1 of the next double-arrow structural unit in the vertical direction, thereby arraying the double-arrow structural units in the horizontal and vertical directions to form a three-dimensional double-arrow negative Poisson's ratio material.

[0051] like Figure 3 and Figure 4As shown, the overall height of the three-dimensional double-arrow negative Poisson's ratio metamaterial is H; the overall width is V; the height of the double-arrow structural unit is n; and the width of the double-arrow structural unit is m. In a specific embodiment, the construction parameters can refer to the following data: d = 2 (mm); L = 26 (mm); θ = 48°; t = 2 (mm); H = 122 (mm); V = 123.2 (mm); m = 42 (mm); n = 30.8 (mm). The three-dimensional double-arrow negative Poisson's ratio metamaterial made with these parameters was subjected to deformation experiments, and its deformation process is shown in the figure below. Figure 7 As shown, at the same time, Figure 8 The force-displacement curve of the three-dimensional double-arrow negative Poisson's ratio material of the present invention is shown. Figure 9 A strain-specific energy absorption curve for the three-dimensional double-arrow negative Poisson's ratio material of the present invention is shown. The curve demonstrates that the negative Poisson's ratio effect of the present invention is superior to that of conventional negative Poisson's ratio metamaterials. The double arrows in the present invention are both orthogonal and opposite in direction. When compressed, the arrows at both ends contract toward the center, achieving a more effective negative Poisson's ratio response. The negative Poisson's ratio effect of the structure also responds more quickly than conventional negative Poisson's ratio metamaterials.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-dimensional double-arrow negative Poisson's ratio material, characterized in that: include: Double-arrow structural units, wherein the double-arrow structural units are interconnected along the x-axis, y-axis, and z-axis directions in three-dimensional space to form an array structure; The double-arrow structural unit comprises two arrow-shaped frame structures pointing in opposite directions, the arrow-shaped frame structure comprising an upper rod (1), two oblique rods (2) symmetrically connected to both ends of the upper rod (1), and two bottom rods (3) connected between the two oblique rods (2), the other ends of the two bottom rods (3) being connected and inclined toward one side of the upper rod (1) to form a concave structure; the two arrow-shaped frame structures pointing in opposite directions are vertically connected at the connection position of the two bottom rods (3); The outer side of the connection position of the oblique rod (2) and the bottom rod (3) is provided with a connection section (4); in the x-axis and y-axis directions, two adjacent double-arrow structural units are connected via the connection section (4); in the z-axis direction, two adjacent double-arrow structural units are connected via the upper rod (1); the length of the bottom rod (3) is greater than the length of the upper rod (1); the position where the bottom rod (3) is connected is connected to a lower rod (5), and the lower rod (5) is parallel to the upper rod (1).

2. The three-dimensional double-arrow negative Poisson's ratio material according to claim 1, characterized in that: The length of the lower rod (5) is equal to that of the upper rod (1).

3. The three-dimensional double-arrow negative Poisson's ratio material according to claim 1, characterized in that: The angle between the oblique rod (2) and the bottom rod (3) is an acute angle.

4. The three-dimensional double-arrow negative Poisson's ratio material according to claim 1, characterized in that: The connecting section (4) is a square.

5. The three-dimensional double-arrow negative Poisson's ratio material according to any one of claims 1 to 4, characterized in that: Two adjacent connection sections (4) are seamlessly connected.

6. A method for manufacturing the three-dimensional double-arrow negative Poisson's ratio material according to any one of claims 1 to 5, characterized in that: include: S1, draw a 2D sketch of the single-arrow structure on the front view datum plane; S2, based on the 2D sketch of the single-arrow structure, offset it in two directions with equal distance, and then stretch it in two directions with equal distance to form a 3D sketch of the single-arrow structure; S3, cut a connecting section at the connection between the oblique rod and the bottom rod to form a three-dimensional model of the upper half of the double-arrow structural unit; S4, mirroring the three-dimensional model of the upper half of the double-arrow structural unit with a reference plane passing through the axis of the lower rod and perpendicular to the front reference plane as a mirror plane, then rotating the mirrored three-dimensional model 90° around the reference axis perpendicular to the lower rod, and combining the two parts to form a double-arrow structural unit; S5, seamlessly connect each double-arrow structural unit in the horizontal direction through the connecting section, and seamlessly connect the upper rod of the previous double-arrow structural unit with the upper rod of the next double-arrow structural unit in the vertical direction, so as to array each double-arrow structural unit in the horizontal and vertical directions to form a three-dimensional double-arrow negative Poisson's ratio material.

7. The method for manufacturing the three-dimensional double-arrow negative Poisson's ratio material according to claim 6, characterized in that: In step S2, the two-way equidistant offset is performed by t / 2, and then the two-way stretching is performed by t / 2.

8. The method for manufacturing the three-dimensional double-arrow negative Poisson's ratio material according to claim 7, characterized in that: In step S3, the connection section is a square with a side length of t.

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