Multi-stable thin conical shell compact arrangement energy absorption metamaterial and preparation method thereof

Abstract

The application discloses a multi-stable thin cone shell dense arrangement energy absorption metamaterial, which comprises a top plate and a bottom plate, and a plurality of arrayed thin cone shell cells are connected between the top plate and the bottom plate; the thin cone shell cells are made of high-elastic rubber and have a hollow structure; each thin cone shell cell is composed of an upper cone shell and an inverted lower cone shell which are sealingly connected; energy absorption unit shafts are arranged at the top of the upper cone shell and the bottom of the lower cone shell; second exhaust holes are formed in the middle of the energy absorption unit shafts and communicate with the inner cavities of the thin cone shell cells; first exhaust holes are formed in the top plate and the bottom plate and communicate with the second exhaust holes; and a preparation method of the multi-stable thin cone shell dense arrangement energy absorption metamaterial is also disclosed. D The energy absorption metamaterial is prepared by printing technology and has the characteristics of multi-stable equilibrium state and sustainable conversion between states, and can be repeatedly used.

Description

Technical Field

[0001] This invention belongs to the field of safety protection technology and relates to multistable thin conical shell densely packed energy-absorbing metamaterials and their preparation methods. Background Technology

[0002] Energy-absorbing materials are a class of materials capable of absorbing and dissipating external energy, thereby protecting systems or the human body from impact damage. When subjected to external impact, they can convert energy into a harmless form through deformation, structural collapse, or physicochemical processes, thus protecting the system from damage. These materials are typically lightweight, high-strength, and impact-resistant, and are widely used in the automotive, aerospace, construction, and sporting goods industries.

[0003] Existing energy-absorbing materials are mostly disposable and cannot be reused. Moreover, they have poor energy absorption effects and are prone to collapse. Summary of the Invention

[0004] One objective of this invention is to provide a multistable thin conical shell densely packed energy-absorbing metamaterial, which solves the problems of existing energy-absorbing materials being prone to collapse and not reusable.

[0005] Another objective of this invention is to provide a method for preparing multistable thin conical shell densely packed energy-absorbing metamaterials.

[0006] The first technical solution adopted in this invention is a multi-stable thin conical shell densely arranged energy-absorbing metamaterial, including a top plate and a bottom plate. Multiple arrayed thin conical shell cells are connected between the top plate and the bottom plate. The thin conical shell cells are made of highly elastic rubber and have a hollow internal structure. Each thin conical shell cell is composed of an upper conical shell and an inverted lower conical shell sealed together. Energy-absorbing unit shafts are provided at the top of the upper conical shell and the bottom of the lower conical shell. A second vent hole communicating with the inner cavity of the thin conical shell cell is opened in the middle of the energy-absorbing unit shaft. A first vent hole communicating with the second vent hole is opened inside the top plate and the bottom plate.

[0007] One or more thin conical shell cells connect the top plate and the bottom plate.

[0008] The bottom surface of the top plate is provided with multiple protruding frustums of cones, each frustum corresponding to a thin conical shell cell. The frustums of cones are inverted, and the bottom end of the frustums of cones is connected and fixed to the top end of the thin conical shell cell at the bottom. The shape of the frustums of cones is the same as that of the lower conical shell.

[0009] The base plate has multiple conical grooves inside, each corresponding to a thin conical shell cell. The top surface of the base plate is provided with a first conical shell that connects to the conical grooves. The top end of the first conical shell is connected and fixed to the bottom end of the top thin conical shell cell. The inner cavity of the conical groove has the same structure as the inner cavity of the lower conical shell, and the first conical shell has the same structure as the upper conical shell.

[0010] The upper and lower conical shells are sealed together by an outer support wall, the thickness of which is the same as the thickness of the lower conical shell.

[0011] It also includes interlayer slabs, which are parallel to the top and bottom slabs. The interlayer slabs are located on the outer side of the supporting outer wall, and the top surface of the interlayer slabs is flush with the top surface of the supporting outer wall.

[0012] The thickness at the joint between the upper and lower parts of the upper conical shell is less than the thickness of the conical shell itself. δ 1. Thickness of the lower conical shell δ 2 is greater than the thickness of the conical shell δ 1. Diameter of the energy-absorbing unit shaft d ≥ δ 2.

[0013] The angle between the lateral surface of the lower conical shell and the horizontal plane is... α The angle between the side surface of the upper conical shell and the horizontal plane is also... α The angle between the lower connection of the upper conical shell and the vertical direction is... β , β ≥ 2 α .

[0014] The length of the lower connection of the upper conical shell is a 1. The length of the connection point on the lower conical shell is... a 2, a 1 ≤a 2. And supports outer wall height h > a 2+ δ 1+ δ 2 / cosα .

[0015] The second technical solution adopted in this invention is a method for preparing multistable thin conical shell densely packed energy-absorbing metamaterials, using thermoplastic polyurethane rubber through 3 D It is manufactured using printing technology.

[0016] The beneficial effect of this invention is that the multistable thin conical shell densely packed energy-absorbing metamaterial is composed of a top plate, a bottom plate, and multiple arrayed thin conical shell cells connected together, and the whole is made of thermoplastic polyurethane rubber through 3 D Fabricated using printing technology, this integrally molded thin conical shell cell consists of an upper conical shell and an inverted lower conical shell sealed together, enabling multi-stable states. This energy-absorbing metamaterial comprises multiple arrayed thin conical shell cells, possessing the characteristics of multiple stable equilibrium states and sustainable transitions between states, and also boasts the advantage of high reusability. Due to the ordered and dense arrangement of the hollow thin conical shells, it also combines lightweight and high energy absorption performance. The unique design and deformation mechanism of this thin conical shell cell successfully resolves the contradiction between repeatability and high energy absorption in traditional energy-absorbing materials. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the multi-stable thin conical shell densely packed energy-absorbing metamaterial of the present invention;

[0018] Figure 2 This is a schematic longitudinal section of the multi-stable thin conical shell densely packed energy-absorbing metamaterial of the present invention; Figure 3 This is a schematic diagram of the thin cone shell cell structure in the multistable thin cone shell densely packed energy-absorbing metamaterial of the present invention; Figure 4 This is a schematic longitudinal section of the thin cone shell cell in the multistable thin cone shell densely packed energy-absorbing metamaterial of the present invention.

[0019] Figure 5 This is a load-displacement diagram of a single thin cone shell cell in the multistable thin cone shell densely packed energy-absorbing metamaterial of this invention; Figure 6 This is a displacement-strain energy curve of a single thin cone shell cell in the multistable thin cone shell densely packed energy-absorbing metamaterial of the present invention; Figure 7 The angle between the side surface of different thin cone shell cells and the horizontal plane in the multistable thin cone shell densely packed energy-absorbing metamaterial of this invention is shown. α The corresponding load-displacement curve; Figure 8 Axial load-displacement curve of an energy-absorbing metamaterial consisting of a three-layer single-row thin conical shell cell array; Figure 9 This is a schematic diagram of the axial compression deformation of a single-row multi-thin conical shell cell.

[0020] In the figure, 1. First vent, 2. Top plate, 3. Frustum, 4. Interlayer plate, 5. Bottom plate, 6. Thin conical shell cell, 7. Conical groove, 8. First conical shell, 9. Energy absorption unit shaft, 10. Supporting outer wall, 11. Second vent, 61. Upper conical shell, 62. Lower conical shell. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 See Figure 1 and Figure 2A multistable, densely packed thin conical shell energy-absorbing metamaterial includes a top plate 2 and a bottom plate 5. Two layers of thin conical shell cells 6 connect the top plate 2 and the bottom plate 5. Each thin conical shell cell 6 is equivalent to one energy-absorbing unit. Each layer has 19 arrayed thin conical shell cells, arranged in 5 rows. The first and fifth rows are symmetrical, each containing 3 cells; the second and fourth rows are symmetrical, each containing 4 cells; the third row contains 5 cells. The density of each layer of thin conical shell cells... The thin conical shell cells are distributed alternately in the previous and next rows. Each thin conical shell cell 6 is made of high elastic rubber. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Energy-absorbing unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second exhaust hole 11 that communicates with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy-absorbing unit shaft 9. A first exhaust hole 1 that communicates with the second exhaust hole 11 is opened inside the top plate 2 and the bottom plate 5.

[0023] Example 2 A multi-stable thin conical shell densely packed energy-absorbing metamaterial includes a top plate 2 and a bottom plate 5. Two layers of thin conical shell cells 6 are connected between the top plate 2 and the bottom plate 5. Each thin conical shell cell 6 is equivalent to one energy-absorbing unit. Each layer has 19 thin conical shell cells arranged in an array. Each thin conical shell cell 6 is made of highly elastic rubber. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Energy-absorbing unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second exhaust hole 11 communicating with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy-absorbing unit shaft 9. A first exhaust hole 1 communicating with the second exhaust hole 11 is opened inside the top plate 2 and the bottom plate 5.

[0024] The bottom surface of the top plate 2 is provided with multiple protruding frustums 3. The frustums 3 correspond one-to-one with the thin conical shell cell 6. The frustums are inverted. The bottom end of the frustum is connected and fixed to the top end of the thin conical shell cell 6 at the bottom. The shape of the frustum is the same as that of the lower conical shell 62.

[0025] Example 3 A multi-stable thin conical shell densely packed energy-absorbing metamaterial includes a top plate 2 and a bottom plate 5. Two layers of thin conical shell cells 6 are connected between the top plate 2 and the bottom plate 5. Each thin conical shell cell 6 is equivalent to one energy-absorbing unit. Each layer has 19 thin conical shell cells arranged in an array. Each thin conical shell cell 6 is made of highly elastic rubber. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Energy-absorbing unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second exhaust hole 11 communicating with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy-absorbing unit shaft 9. A first exhaust hole 1 communicating with the second exhaust hole 11 is opened inside the top plate 2 and the bottom plate 5.

[0026] The bottom surface of the top plate 2 is provided with multiple protruding frustums 3. The frustums 3 correspond one-to-one with the thin conical shell cell 6. The frustums are inverted. The bottom end of the frustum is connected and fixed to the top end of the thin conical shell cell 6 at the bottom. The shape of the frustum is the same as that of the lower conical shell 62.

[0027] The bottom plate 5 has multiple conical grooves 7 inside, and each conical groove 7 corresponds to a thin conical shell cell 6. The top surface of the bottom plate 5 is provided with a first conical shell 8 that is sealed and connected to the conical groove. The top end of the first conical shell 8 is connected and fixed to the bottom end of the top thin conical shell cell 6. The inner cavity of the conical groove has the same structure as the inner cavity of the lower conical shell 62, and the first conical shell has the same structure as the upper conical shell 61.

[0028] The upper conical shell 61 and the lower conical shell 62 are sealed together by the outer support wall 10, and the thickness of the support wall 10 is the same as the thickness of the lower conical shell 62.

[0029] Example 4 A multi-stable thin conical shell densely packed energy-absorbing metamaterial includes a top plate 2, a bottom plate 5, and two interlayer plates 4. The interlayer plates 4 are parallel to the top plate 2 and the bottom plate 5. Two layers of thin conical shell cells 6 are connected between the top plate 2 and the bottom plate 5. Each thin conical shell cell 6 is equivalent to one energy-absorbing unit. Each layer has 19 thin conical shell cells arranged in an array. Each thin conical shell cell 6 is made of highly elastic rubber. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Energy-absorbing unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second vent hole 11 communicating with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy-absorbing unit shaft 9. A first vent hole 1 communicating with the second vent hole 11 is opened in the interior of the top plate 2 and the bottom plate 5.

[0030] The bottom surface of the top plate 2 is provided with multiple protruding frustums 3. The frustums 3 correspond one-to-one with the thin conical shell cell 6. The frustums are inverted. The bottom end of the frustum is connected and fixed to the top end of the thin conical shell cell 6 at the bottom. The shape of the frustum is the same as that of the lower conical shell 62.

[0031] The bottom plate 5 has multiple conical grooves 7 inside, and each conical groove 7 corresponds to a thin conical shell cell 6. The top surface of the bottom plate 5 is provided with a first conical shell 8 that is sealed and connected to the conical groove. The top end of the first conical shell 8 is connected and fixed to the bottom end of the top thin conical shell cell 6. The inner cavity of the conical groove has the same structure as the inner cavity of the lower conical shell 62, and the first conical shell has the same structure as the upper conical shell 61.

[0032] The upper conical shell 61 and the lower conical shell 62 are sealed together by the outer support wall 10, and the thickness of the support wall 10 is the same as the thickness of the lower conical shell 62.

[0033] Interlayer plate 4 is located on the outer side of the supporting outer wall 10. The interlayer plate connects the same thin conical shell cell 6 into a whole. The top surface of the interlayer plate 4 is flush with the top surface of the supporting outer wall 10.

[0034] Example 5 A multi-stable thin conical shell densely packed energy-absorbing metamaterial includes a top plate 2, a bottom plate 5, and two interlayer plates 4. The interlayer plates 4 are parallel to the top plate 2 and the bottom plate 5. One or more layers of thin conical shell cells 6 are connected between the top plate 2 and the bottom plate 5. Each thin conical shell cell 6 is made of highly elastic rubber and is equivalent to one energy-absorbing unit. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Energy-absorbing unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second vent hole 11 communicating with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy-absorbing unit shaft 9. A first vent hole 1 communicating with the second vent hole 11 is opened inside the top plate 2 and the bottom plate 5.

[0035] The bottom surface of the top plate 2 is provided with multiple protruding frustums 3. The frustums 3 correspond one-to-one with the thin conical shell cell 6. The frustums are inverted. The bottom end of the frustum is connected and fixed to the top end of the thin conical shell cell 6 at the bottom. The shape of the frustum is the same as that of the lower conical shell 62.

[0036] The bottom plate 5 has multiple conical grooves 7 inside, and each conical groove 7 corresponds to a thin conical shell cell 6. The top surface of the bottom plate 5 is provided with a first conical shell 8 that is sealed and connected to the conical groove. The top end of the first conical shell 8 is connected and fixed to the bottom end of the top thin conical shell cell 6. The inner cavity of the conical groove has the same structure as the inner cavity of the lower conical shell 62, and the first conical shell has the same structure as the upper conical shell 61.

[0037] The upper conical shell 61 and the lower conical shell 62 are sealed together by the outer support wall 10, and the thickness of the support wall 10 is the same as the thickness of the lower conical shell 62.

[0038] Interlayer plate 4 is located on the outer side of the supporting outer wall 10. The interlayer plate connects the same thin conical shell cell 6 into a whole. The top surface of the interlayer plate 4 is flush with the top surface of the supporting outer wall 10.

[0039] See Figure 3 and Figure 4 The length of the upper conical shell is l The thickness at the connection between the upper and lower parts of the upper conical shell 61 is less than the thickness of the conical shell itself. δ 1. Forming a flexible connection or hinge-like connection; lower conical shell thickness 62. δ 2 is greater than the thickness of the conical shell δ 1. To ensure that the upper half of the thin conical shell cell (i.e., the energy-absorbing unit) deforms while the lower half remains unchanged. The diameter of the energy-absorbing unit shaft 9. d ≥ δ 2. The angle between the side surface of the lower conical shell 62 and the horizontal plane is... α The angle between the side surface of the upper conical shell 61 and the horizontal plane is also... α The angle between the lower connection of the upper conical shell 61 and the vertical direction is... β , β ≥2 α .

[0040] The length of the lower connection of the upper conical shell 61 is a 1. The length of the connection point on the lower conical shell 62 is... a 2, a 1 ≤a 2. And supports an outer wall height of 10. h > a 2+ δ 1+ δ 2 / cosα .

[0041] Example 6 A method for fabricating a multistable thin-conical-shell densely packed energy-absorbing metamaterial involves using thermoplastic polyurethane rubber to create a single, integrally molded structure. First, a three-dimensional digital model of the multistable thin-conical-shell densely packed energy-absorbing metamaterial is created on a computer. Then, using thermoplastic polyurethane rubber as the raw material, the entire multistable thin-conical-shell densely packed energy-absorbing metamaterial is formed by layer-by-layer printing. Thermoplastic polyurethane rubber, also known as thermoplastic polyurethane elastomer or TPU for short, has properties between plastics and rubber, exhibiting a unique "soft-hard" multi-segment structure with excellent elasticity, abrasion resistance, tear resistance, and chemical resistance.

[0042] The multi-stable thin conical shell densely packed energy-absorbing metamaterial structure includes a top plate 2, a bottom plate 5, and two interlayer plates 4. The interlayer plates 4 are parallel to the top plate 2 and the bottom plate 5. One or more arrays of thin conical shell cells 6 are connected between the top plate 2 and the bottom plate 5. According to actual needs, the size, number, and stacking of single-layer transverse thin conical shell cells can be designed, and the connection between multiple conical shells is stable.

[0043] In each layer of thin conical shell cells 6, the thin conical shell cells are distributed in a cross pattern in the front and back rows. Each thin conical shell cell 6 is composed of an upper conical shell 61 and an inverted lower conical shell 62 sealed together. The interior of the thin conical shell cell 6 is a hollow structure. Each thin conical shell cell 6 is equivalent to one energy absorption unit. Energy absorption unit shafts 9 are provided at the top of the upper conical shell 61 and the bottom of the lower conical shell 62. A second exhaust hole 11 that communicates with the inner cavity of the thin conical shell cell 6 is opened in the middle of the energy absorption unit shaft 9. A first exhaust hole 1 that communicates with the second exhaust hole 11 is opened inside the top plate 2 and the bottom plate 5.

[0044] The bottom surface of the top plate 2 is provided with multiple protruding frustums 3, each corresponding to a thin conical shell cell 6. The frustums are inverted, and their bottom ends are connected and fixed to the top ends of the bottom thin conical shell cell 6. The shape of the frustums is the same as that of the lower conical shell 62. The bottom plate 5 has multiple conical grooves 7 inside, each corresponding to a thin conical shell cell 6. The top surface of the bottom plate 5 is provided with a first conical shell 8 that is sealed and connected to the conical grooves. The top end of the first conical shell 8 is connected and fixed to the bottom end of the top thin conical shell cell 6. The inner cavity of the conical groove is the same as that of the lower conical shell 62, and the first conical shell is the same as that of the upper conical shell 61.

[0045] The upper conical shell 61 and the lower conical shell 62 are sealed together by the outer supporting wall 10, the thickness of which is the same as the thickness of the lower conical shell 62. The interlayer plate 4 is located on the outer surface of the supporting wall 10, and the interlayer plate connects the same thin conical shell cell 6 into a whole. The top surface of the interlayer plate 4 is flush with the top surface of the supporting wall 10.

[0046] The thickness of the upper and lower joint of the upper conical shell 61 is less than the thickness of the conical shell. δ 1. Lower conical shell, 62mm thickness δ 2 is greater than the thickness of the conical shell δ 1. Diameter of the energy-absorbing unit shaft 9 d ≥ δ 2. The angle between the side surface of the lower conical shell 62 and the horizontal plane is... α The angle between the side surface of the upper conical shell 61 and the horizontal plane is also... α The angle between the lower connection of the upper conical shell 61 and the vertical direction is... β , β ≥2 α The length of the lower connection point of the upper conical shell is... a1. The length of the connection point on the lower conical shell is... a 2, a 1 ≤a 2. And supports outer wall height h > a 2+ δ 1+ δ 2 / cosα .

[0047] Except for 3 D In addition to the integrated printing technology, the multi-stable thin conical shell densely packed energy-absorbing metamaterial of this invention can also be prepared by other methods. For example, the upper conical shell can be made of a highly elastic rubber material, and the lower conical shell and the supporting outer wall can be made of a rigid material (hard plastic, stainless steel plate). The upper conical shell, the lower conical shell, and the supporting outer wall are connected and fixed by adhesive.

[0048] Figure 5 This is a load-displacement diagram of a single thin conical shell cell in the multistable thin conical shell densely packed energy-absorbing metamaterial of this invention. As can be seen from the diagram, the force-displacement curve of the thin conical shell cell intersects the displacement axis at three points: the origin, ... C Dot and E The origin is the initial stable state of a cell when it is not under load, i.e., the first stable state. C The point corresponds to an unstable equilibrium state that occurs during the steady-state transition of a buckling step in a conical shell. In this state, the cell has a local maximum potential energy and cannot remain stable. E The point corresponds to the second stable state reached by the cone-shell cell after completing the buckling step. D The point corresponds to the critical force of the second stable state of the cone-shell cell. When the reverse force (tension) acting on the cell in the second stable state exceeds... D The cell will only return to its initial stable state when the load corresponding to the point is applied.

[0049] Figure 6 This is a displacement-strain energy curve of a single thin cone shell cell in the multi-stable thin cone shell densely packed energy-absorbing metamaterial of this invention, showing the strain energy of the thin cone shell cell from the first stable equilibrium state to the unstable equilibrium state. E 1 and strain energy from the second stable equilibrium state to the unstable equilibrium state E 2. Reset performance coefficient η =16.8% ( η = E 2 / E 1×100%, used to analyze the ease with which a cell can recover to its first stable state (the smaller the η value, the easier the reset performance), exhibiting the advantages of high energy absorption and easy recovery to the initial state.

[0050] When the top plate is subjected to a normal impact, the impact load causes the upper conical shell 61 to deform axially through the energy-absorbing unit shaft, thereby storing external energy in the form of deformation energy. When the angle between the generatrix of the thin conical shell and its bottom surface... α Not exceeding the critical angle α cr As the impact load continues to increase, the deformation of the upper conical shell 61 continues to increase and at a certain moment it suddenly buckles and becomes unstable, rapidly deforming to a symmetrical position of its initial shape (at the inner wall of the lower conical shell 62), reaching the second stable equilibrium state (see...). Figure 5 and Figure 7 ).when α Angle exceeding the critical angle α cr At this time, a new stable equilibrium state will appear between the two stable equilibrium states mentioned above: as the axial impact load increases, the deformation of the upper conical shell 61 continues to increase and suddenly buckles and becomes unstable at a certain moment, rapidly deforming to a new equilibrium state, but without compressing and deforming to the antisymmetric position, which is called the second stable equilibrium state; if the load is terminated at this time, the thin conical shell maintains this second stable state; thereafter, the load is continuously applied, deforming to the antisymmetric position, and finally the upper conical shell 61 contacts the inner wall of the lower conical shell 62, reaching the third stable equilibrium state.

[0051] Figure 7 Showing the angle between the lateral side of the thin conical shell cell and the horizontal plane. α The effect on the load-displacement curve, when α At ≤45°, this cell exhibits obvious bistable mechanical properties. With... α As the angle increases, the peak load of energy absorbed in the first steady state of the cell ( F A The increase in displacement of the unstable equilibrium point indicates an overall shift in the structural initial resistance to deformation and improved first-steady-state stability. This means that the cell requires greater compressive deformation to achieve a steady-state transition. Simultaneously, within the load region... E 2 and critical rebound load (load valley value) F D The number of cells in the brain also increased significantly, indicating that... α The corner also affects the energy absorption and recovery capabilities of the cell. Its recovery performance coefficient... η Follow α The increases were 16.8%, 23.3%, 26.7%, 25.2%, and 23.2% respectively. Based on this, appropriate sizes can be designed according to different working conditions. α horn.

[0052] Figure 8 This is an axial load-displacement curve of a three-layer, single-row thin conical shell cell array energy-absorbing metamaterial. The area enclosed by this curve and the horizontal displacement axis represents the strain energy stored throughout the process. Figure 9This is a schematic diagram of the axial compressive deformation of a single-row multi-thin conical shell cell. The thickness of the upper conical shell of this row of multi-thin conical shell cells is... δ 1. From top to bottom, the deformation gradually decreases, so when the top is compressed and deformed, the deformation first occurs in the thinnest conical shell cell at the bottom (the thinnest upper conical shell), and finally in the thinnest conical shell cell at the top (the thickest upper conical shell). (Combined with...) Figure 8 and Figure 9 As can be seen, the energy absorption effect of the array structure energy-absorbing metamaterial is proportional to the number of thin conical shell cell layers within it.

[0053] In this invention, the energy-absorbing metamaterial with a densely packed, multi-stable thin-conical shell structure comprises thin-conical shell cells. Each cell consists of an upper conical shell 61 and an inverted lower conical shell 62, sealed together. When fully compressed to the reverse position (i.e., the upper conical shell 61 deforms to its symmetrical position from its initial shape, with the upper conical shell 61 contacting the inner wall of the lower conical shell 62), it enters another stable state. This energy-absorbing metamaterial includes multiple arrayed thin-conical shell cells, possessing multiple stable equilibrium states and the ability to sustain transitions between states, and exhibiting the advantage of high reusability. Furthermore, due to the ordered, densely packed structure of the hollow thin-conical shells, it also combines lightweight design with high energy absorption performance. Furthermore, by setting the upper conical shell wall thickness of each layer of thin conical shell cells in a densely packed, multi-stable thin conical shell energy-absorbing metamaterial to vary in a regular manner, the deformation sequence can also be controlled. For example, if the top surface of the energy-absorbing metamaterial is the stress-bearing surface, and the upper conical shell wall thickness of the thin conical shell cells gradually decreases from top to bottom, then when the top surface is compressed, the bottom thin conical shell cells deform first, followed by deformation upwards. Conversely, if the upper conical shell wall thickness of the thin conical shell cells gradually increases from top to bottom, then when the top surface is compressed, the top thin conical shell cells deform first, followed by deformation downwards. This unique design and deformation mechanism of the thin conical shell cells successfully resolves the contradiction between repeatability and high energy absorption in traditional energy-absorbing materials, providing a core solution for protection technology.

[0054] This invention relates to a multistable, thin-shell, densely packed energy-absorbing metamaterial that can be used in buffering, impact protection, and other protective applications. When the protected object is subjected to a collision impact, the energy generated by the impact load can be effectively absorbed layer by layer by this stacked device, achieving energy dissipation at each stage, thereby reducing equipment damage, minimizing personal injury, or protecting equipment from damage.

Claims

1. A multistable thin conical shell densely packed energy-absorbing metamaterial, characterized in that, It includes a top plate (2) and a bottom plate (5). Multiple thin conical shell cells (6) are connected between the top plate (2) and the bottom plate (5). The thin conical shell cells (6) are made of high elastic rubber and have a hollow structure inside. Each thin conical shell cell (6) is composed of an upper conical shell (61) and an inverted lower conical shell (62) sealed together. The top of the upper conical shell (61) and the bottom of the lower conical shell (62) are provided with energy-absorbing unit shafts (9). The middle part of the energy-absorbing unit shaft (9) is provided with a second exhaust hole (11) that communicates with the inner cavity of the thin conical shell cell (6). The top plate (2) and the bottom plate (5) are provided with a first exhaust hole (1) that communicates with the second exhaust hole (11).

2. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 1, characterized in that, One or more thin conical shell cells (6) are connected between the top plate (2) and the bottom plate (5).

3. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 1, characterized in that, The bottom surface of the top plate (2) is provided with multiple protruding frustums (3). The frustums (3) correspond one-to-one with the thin conical shell cell (6). The frustums (3) are inverted. The bottom end of the frustums (3) is connected and fixed to the top end of the thin conical shell cell (6) at the bottom. The shape of the frustums (3) is the same as that of the lower conical shell (62).

4. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 1 or 3, characterized in that, The bottom plate (5) has multiple conical grooves (7) inside, and the conical grooves (7) correspond one-to-one with the thin conical shell cells (6). The top surface of the bottom plate (5) is provided with a first conical shell (8) connected to the conical grooves (7). The top end of the first conical shell (8) is connected and fixed to the bottom end of the top thin conical shell cell (6). The inner cavity of the conical groove (7) has the same structure as the inner cavity of the lower conical shell (62), and the first conical shell (8) has the same structure as the upper conical shell (61).

5. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 1, characterized in that, The upper conical shell (61) and the lower conical shell (62) are sealed together by an outer support wall (10), the thickness of which is the same as the thickness of the lower conical shell (62).

6. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 5, characterized in that, It also includes an interlayer plate (4), which is parallel to the top plate (2) and the bottom plate (5). The interlayer plate (4) is located on the outer side of the supporting outer wall (10), and the top surface of the interlayer plate (4) is flush with the top surface of the supporting outer wall (10).

7. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 6, characterized in that, The thickness of the upper conical shell (61) at the connection between the upper and lower parts is less than the thickness of the conical shell itself. δ 1. Thickness of the lower conical shell (62) δ 2 is greater than the thickness of the conical shell δ 1. Diameter of the energy-absorbing unit shaft (9) d ≥ δ 2.

8. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 7, characterized in that, The angle between the side surface of the lower conical shell (62) and the horizontal plane is: α The angle between the side surface of the upper conical shell (61) and the horizontal plane is also... α The angle between the lower connection of the upper conical shell (61) and the vertical direction is... β , β ≥2 α .

9. The multistable thin conical shell densely packed energy-absorbing metamaterial according to claim 8, characterized in that, The length of the lower connection of the upper conical shell (61) is a 1. The length of the connection point on the lower conical shell (62) is a 2, a 1 ≤a 2, and supports the height of the outer wall (10). h > a 2+ δ 1+ δ 2 / cos α .

10. The method for preparing the multistable thin conical shell densely packed energy-absorbing metamaterial according to any one of claims 1 to 9, characterized in that, Thermoplastic polyurethane rubber is used through 3 D It is manufactured using printing technology.

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