Design and reconstruction method of an environmentally aware paper-cut metamaterial with simplified shape memory effect

Abstract

A design of an environmentally-aware paper-cut metamaterial with a simplified shape memory effect and a reconstruction method thereof, specifically relates to the technical field of intelligent responsive shape memory metamaterials. The present invention aims to solve the problem that existing shape memory materials lack multi-shape memory capabilities and are often accompanied by undesirable rebound, resulting in insufficient precision, strong chemical dependence, and slow response speed. The paper-cut structure of the present invention includes a plurality of unit cells, each unit cell including two boundary units and a plurality of rotation units. The two boundary units are arranged relative to each other, and a cavity is formed between the two boundary units. The plurality of rotation units can move inside and outside the cavity between the two boundary units. The two boundary units and the plurality of rotation units are connected into an integral structure by a ligament assembly. The plurality of unit cells are arranged in sequence, and the adjacent boundary units between each two adjacent unit cells are fixedly connected.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent response shape memory metamaterials, and in particular to a design of an environment-aware paper-cut metamaterial with a simplified shape memory effect and a reconstruction method thereof. Background Art

[0002] In nature, biological materials exhibit a wide range of intelligent behaviors. These behaviors are often triggered and induced in response to external stimuli, such as the Venus flytrap's rapid response to touch, the opening and closing of pine cones in response to humidity fluctuations, and the color change of chameleons in response to their environment. These response mechanisms have inspired the development of smart materials, leading to a gradual shift in the design of mechanical metamaterials and shape memory materials that can respond to external stimuli. Among these materials, shape memory materials, which can recover from a temporary shape to a permanent one in response to external stimuli (such as temperature, light, or humidity), have become a hot topic of research. However, existing shape memory materials have significant limitations: First, most shape memory materials can only remember one or two shapes, making them difficult to achieve multi-shape memory. Second, these materials often experience undesirable rebound during recovery, resulting in insufficient shape recovery precision. Furthermore, these materials typically rely on chemical composition manipulation or complex thermomechanical programming to achieve memory, making the preparation process cumbersome and difficult to control. Therefore, to achieve a richer range of intelligent response properties, it is of great significance to develop metamaterials with simplified shape memory effects that are simple in structure, responsive, and reprogrammable. Summary of the Invention

[0003] To address the challenges of existing shape memory materials, which often suffer from insufficient multi-shape memory capabilities and are often accompanied by undesirable rebound, resulting in insufficient precision, strong chemical dependence, and slow response speed, this invention proposes a design and reconstruction method for an environmentally aware paper-kirigami metamaterial with a simplified shape memory effect. Through ingenious structural design and strategic combination of component materials, this invention achieves multi-shape memory effects and rapid response without relying on chemical manipulation, providing insights and guidance for a variety of intelligent applications, including smart cooling systems, temperature sensors, and fire alarm systems.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] An environmentally-aware paper-cut metamaterial design with a simplified shape memory effect includes multiple unit cells, each of which includes two boundary units and multiple rotation units. The two boundary units are arranged opposite to each other, forming a cavity between the two boundary units. The multiple rotation units can move in and out of the cavity between the two boundary units. The two boundary units and the multiple rotation units are connected into an integral structure through a ligament assembly. The multiple unit cells are arranged in sequence, and the adjacent boundary units between each two adjacent unit cells are fixedly connected.

[0006] Furthermore, the boundary unit is a frame with an open inner end.

[0007] Furthermore, the outer contours of the plurality of rotating units match the contour of the cavity between the two boundary units.

[0008] Furthermore, the ligament assembly includes a boundary ligament and a rotational ligament. The rotational unit is connected to the adjacent boundary unit via the boundary ligament, and every two adjacent rotational units are connected via the rotational ligament.

[0009] Furthermore, one end of the boundary ligament is connected to the side wall of the open end of the boundary unit, and the other end of the boundary ligament is connected to the adjacent inner corner of the adjacent rotation unit.

[0010] Furthermore, the plurality of rotating units can rotate inside and outside the cavity of the boundary unit by mechanical loading, and the plurality of rotating units can rotate and return to their initial positions by external stimulation.

[0011] Furthermore, the boundary unit is made of material A, which is a material sensitive to external stimuli; the rotation unit is made of material B, which is a material insensitive to external stimuli; and the elastic modulus of material A is greater than the elastic modulus of material B under initial conditions.

[0012] Furthermore, the external stimulus includes one or more of temperature, humidity, light or magnetic field.

[0013] A reconstruction method for the design of an environmentally aware kirigami metamaterial with simplified shape memory effect includes the following steps:

[0014] Under initial conditions, mechanical loading is used to induce the rotation of the rotation unit, resulting in the shape reconstruction of the unit cell. Since the elastic modulus of material A applied to the boundary unit is higher than that of material B applied to the rotation unit under initial conditions, the boundary unit can provide constraints to maintain the reconstructed geometry, thereby realizing the programmable morphology of the unit cell.

[0015] When the external stimulus input changes, the elastic modulus of material A applied to the boundary unit decreases when it reaches a critical value, causing the boundary unit with material A as the component material to become soft and the constraint ability to decrease. The reconstructed rotation unit will restore the shape before reconstruction to achieve the shape memory effect.

[0016] Furthermore, the mechanical loading includes one or more of stretching, compression or bending.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Simplified multi-shape memory effect: No complex chemical composition adjustment is required, and multi-shape programming and switching can be achieved through simple geometric structure design and strategic combination of commercially available materials;

[0019] 2. Composite deformation mode: It can realize a variety of mechanical deformations, including stretching, bending, compression, etc., and can achieve shape recovery in multiple directions;

[0020] 3. Multifunctionality: The structure has the characteristics of environmental change-induced shape recovery and mechanical property switching, and can be applied to flexible robots, adaptive sensors and self-powered drives. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the stretching process of the paper-kirigami metamaterial unit cell when the rotating unit is a square in the present invention;

[0022] Figure 2 It is a structural schematic diagram of the compression process of the paper-kirigami metamaterial unit cell when the rotation unit is a square in the present invention;

[0023] Figure 3 It is a structural schematic diagram of the stretching process of the paper-kirigami metamaterial unit cell when the rotation unit is a triangle in the present invention;

[0024] Figure 4 It is a structural schematic diagram of the compression process of the paper-kirigami metamaterial unit cell when the rotation unit is a triangle in the present invention;

[0025] Figure 5 This is a structural diagram of the bending process of the paper-cut metamaterial unit cell when the rotating unit is an irregular shape in the present invention. Figure 1 ;

[0026] Figure 6 This is a structural diagram of the bending process of the paper-cut metamaterial unit cell when the rotating unit is an irregular shape in the present invention. Figure 2 ;

[0027] Figure 7 Schematic diagram of shape change of multi-shape memory in the present invention;

[0028] Figure 8 is a graph showing the relationship between the elastic modulus of the component materials and temperature;

[0029] Figure 9 This is a diagram illustrating an embodiment of the programmable morphology and shape memory effect of an axially deformable unit-cell kirigami structure;

[0030] Figure 10 This is a diagram illustrating an embodiment of the programmable morphology and shape memory effect of a bent and deformed unit-cell kirigami structure;

[0031] Figure 11This is a diagram showing an embodiment of the programmable morphology and shape memory effect of a multicellular kirigami structure;

[0032] Figure 12 It is a schematic diagram of an environmentally aware, shrinkable, multicellular paper-cut structure in a planar configuration;

[0033] Figure 13 It is a schematic diagram of an environmentally aware expandable multi-cellular paper-cut structure in a planar configuration;

[0034] Figure 14 This is a schematic diagram of another type of environmentally aware shrinkable multicellular paper-cut structure in a planar configuration;

[0035] Figure 15 It is another schematic diagram of an environmentally aware expandable multi-cellular paper-cut structure in a planar configuration;

[0036] Figure 16 It is a schematic diagram of a three-dimensional axially expanded (contracted) multi-cellular paper-cut structure in a cubic configuration;

[0037] Figure 17 It is a schematic diagram of a three-dimensional axially expanded (contracted) multi-cellular paper-cut structure configured as a cylinder;

[0038] Figure 18 It is a schematic diagram of a three-dimensional non-axially expanded (contracted) multi-cellular paper-cut structure in a cubic configuration;

[0039] Figure 19 It is a schematic diagram of a three-dimensional non-axially expanded (contracted) multi-cellular paper-cut structure configured as a cylinder;

[0040] Figure 20 This is an embodiment diagram of the temperature rising alarm process of a temperature alarm device based on a rotating square paper-cut structure unit cell;

[0041] Figure 21 This is an example diagram of the early warning process of a temperature alarm based on a rotating square paper-cut structure unit cell approaching a fire source;

[0042] Figure 22 This is an example diagram of the throwing process of a thrower based on a rotating triangle paper-cut structure unit cell;

[0043] Figure 23 This is an example diagram of the robot grasping process based on the multi-cellular paper-kirigami structure;

[0044] Figure 24 This is an example diagram of the release process of a robot based on a multi-cellular paper-kirigami structure. DETAILED DESCRIPTION

[0045] Specific implementation method 1: Combination Figures 1 to 24To describe this embodiment, an environmentally-aware paper-cut metamaterial design with a simplified shape memory effect described in this embodiment includes a plurality of unit cells, wherein the unit cell includes two boundary units 1 and a plurality of rotation units 2. The two boundary units 1 are arranged opposite to each other, and a cavity is formed between the two boundary units 1. The plurality of rotation units 2 can move in and out of the cavity between the two boundary units 1. The two boundary units 1 and the plurality of rotation units 2 are connected into an integral structure through a ligament assembly. The plurality of unit cells are arranged in sequence, and the adjacent boundary units 1 between each two adjacent unit cells are fixedly connected.

[0046] The core of the present invention lies in the structural design and the strategic matching of component materials. In terms of structural design, the present invention proposes a variety of paper-cut structures, which are composed of single or multiple dual / multi-stable geometric modules and can present rich geometric shapes in plane and spatial forms. In terms of the strategic combination of component materials, the structure adopts two commercially available materials with different environmentally dependent elastic moduli, realizes the switching of different shapes through environmental changes, and performs stability transition in multiple mechanical modes (such as stretching, bending, compression, etc.), realizing multifunctional applications such as shape recovery, stiffness switching and rapid response.

[0047] Specifically, the kirigami structure is composed of a boundary unit 1 that provides boundary constraints and a modular rotation unit 2 with rotation characteristics. It should be noted that the boundary unit 1 and the rotation unit 2 are only exemplary, and their geometric shapes can be freely selected. Figures 1 to 6 As shown, the boundary unit 1 can include various geometric shapes such as rectangles and triangles, and the rotation unit 2 can include various geometric shapes such as squares, triangles, and irregular shapes. Through symmetrical or asymmetrical designs, various deformation modes such as stretching, compression, and bending can be achieved in bi- / multi-stable switching.

[0048] Another necessary condition for achieving the programmable morphology of the paper-cut structure is the strategic combination of component materials. The present invention uses two materials with different environment-dependent elastic moduli to construct the paper-cut structure, and these two materials are material A and material B. The selection of the two materials is not specific, but must meet the following requirements: the two materials have different sensitivities to the same stimulus (such as temperature, humidity, light, etc.). Specifically, material A should be sensitive to stimuli, and changes in stimulus input can cause significant changes in the elastic modulus of the material (the elastic modulus decreases rapidly when the environmental change reaches a critical value). On the contrary, material B should be a material that is insensitive to stimuli, and the elastic modulus of the material will not change significantly when the stimulus input changes. Moreover, under initial conditions, the elastic modulus of material A should be greater than the elastic modulus of material B. Of the two materials, material A is applied to boundary unit 1 and material B is applied to rotation unit 2.

[0049] Its mechanism of action is as follows: under initial conditions, mechanical loading can induce the rotation of the rotation unit 2, resulting in shape reconstruction. Because the elastic modulus of material A applied to the boundary unit 1 is higher than that of material B applied to the rotation unit 2 under initial conditions, the boundary unit 1 can provide a sufficiently strong constraint to maintain the reconstructed geometry, thereby achieving a programmable morphology. When the external stimulus input changes, the elastic modulus of material A decreases rapidly when it reaches a critical value, causing the boundary unit 1 composed of material A to gradually soften and its constraint capacity to gradually decrease. The reconstructed rotation unit 2 restores its pre-reconstruction shape to achieve a shape memory effect.

[0050] Its multi-shape memory is reflected in that compared with traditional shape memory materials, the multi-stable structure of the present invention has rich shape and geometric changes through the orderly arrangement of unit cells. Figure 7 As shown in the figure, examples of polyhedral forms of kirigami structures and some of their programmable forms are provided. Based on the above mechanism, these programmable forms can return to their original shapes through external stimulation, thus achieving shape memory effect.

[0051] Its simplified shape memory effect is reflected in the following: Compared with traditional shape memory materials, this invention achieves the shape memory effect through structural design and a strategic combination of commercially available materials, avoiding complex chemical composition control and multi-step thermomechanical programming. Specifically, in terms of chemical composition control, traditional shape memory materials generally rely on changes in the material's chemical composition to achieve response, often requiring the introduction of special chemical components within the material or a complex synthesis process to adjust the memory properties. In contrast, the present invention only uses two commercially available materials with different environmentally dependent elastic moduli, without changing the material's chemical properties, and can achieve shape recovery through the material's physical properties. This method avoids the tedious process of chemical control, making the material preparation simpler and suitable for large-scale production. In terms of multi-step mechanical programming, traditional shape memory materials generally require a complex programming process involving multiple steps of heating, cooling, and external force application to achieve a single or limited shape memory effect. However, the paper-kirigami structure of the present invention uses a dual-material combination with different sensitivity responses to environmental changes. In the absence of external stimulation, the structural morphology can be adjusted by external force to form a stable temporary shape, eliminating the need for multiple heating and external force reprogramming. After the introduction of external stimulation, the balance of the temporary shape is destroyed due to the change in the elastic modulus of the component materials in the structure, triggering the automatic recovery of the shape, thus realizing the shape memory effect, providing an efficient and low-cost design method for shape memory metamaterials.

[0052] Specific implementation method 2: Combination Figures 1 to 19 In this embodiment, the boundary unit 1 is a frame with an open inner end. The undisclosed technical features of this embodiment are the same as those of the first embodiment.

[0053] Specific implementation method three: Combination Figures 1 to 19 In this embodiment, the outer contours of the plurality of rotating units 2 match the contours of the cavity between the two boundary units 1. The undisclosed technical features of this embodiment are the same as those of the second embodiment.

[0054] Specific implementation method four: Combination Figures 1 to 19 This embodiment describes the ligament assembly, which includes a boundary ligament 3 and a rotational ligament 4. A rotational unit 2 is connected to an adjacent boundary unit 1 via a boundary ligament 3, and each adjacent rotational unit 2 is connected via a rotational ligament 4. The undisclosed technical features of this embodiment are the same as those of the third embodiment.

[0055] Specific implementation method five: Combination Figures 1 to 19 In this embodiment, one end of the boundary ligament 3 is connected to the side wall of the open end of the boundary unit 1, and the other end of the boundary ligament 3 is connected to the adjacent inner corner of the adjacent rotation unit 2. The undisclosed technical features of this embodiment are the same as those of the fourth embodiment.

[0056] Specific implementation method six: combination Figures 1 to 19 In this embodiment, the plurality of rotating units 2 can be rotated within and outside the cavity of the boundary unit 1 by mechanical loading, and the plurality of rotating units 2 can be rotated back to their initial positions by external stimulation. The undisclosed technical features of this embodiment are the same as those of the first embodiment.

[0057] Specific implementation method seven: combination Figures 1 to 19 To describe this embodiment, the boundary element 1 is made of material A, which is sensitive to external stimuli, and the rotation element 2 is made of material B, which is insensitive to external stimuli. Under initial conditions, the elastic modulus of material A is greater than the elastic modulus of material B. The undisclosed technical features of this embodiment are the same as those of the sixth embodiment.

[0058] Specific implementation method eight: combination Figures 1 to 19 In this embodiment, the external stimulus includes one or more of temperature, humidity, light, or magnetic field. The undisclosed technical features in this embodiment are the same as those in the seventh embodiment.

[0059] Specific implementation method nine: Combination Figures 1 to 19 This embodiment describes a reconstruction method for an environment-aware paper-cut metamaterial design with a simplified shape memory effect, including the following steps:

[0060] Under initial conditions, mechanical loading is used to induce the rotation of the rotation unit 2, resulting in the reshaping of the unit cell. Since the elastic modulus of material A applied to the boundary unit 1 is higher than that of material B applied to the rotation unit 2 under initial conditions, the boundary unit 1 can provide a sufficiently strong constraint to maintain the reconstructed geometry, thereby realizing the programmable morphology of the unit cell.

[0061] When the external stimulus input changes, the elastic modulus of material A applied to the boundary unit 1 decreases when it reaches a critical value, causing the boundary unit 1 with material A as a component material to become soft and the constraint ability to decrease. The reconstructed rotation unit 2 will restore the shape before reconstruction to achieve the shape memory effect.

[0062] Specific implementation method ten: Combination Figures 1 to 19 In this embodiment, the mechanical loading includes one or more of stretching, compression, and bending. The undisclosed technical features in this embodiment are the same as those in the ninth embodiment.

[0063] In all the examples provided below, temperature stimulation is used as the environmental input. Material A is a temperature-sensitive material, and the commercially available TOP 31B (black) is selected. Material B is a temperature-insensitive material, TPU 90A (white). The elastic modulus curves of the two materials as they change with temperature are shown in Figure 2. Figure 8 As shown in the figure, material A is applied to the boundary element 1, and material B is applied to the rotation element 2. It should be noted that the temperature stimulation and material selection here are exemplary. As long as the design principles of the present invention are followed, the paper-cut structure of the present invention can be applied to other stimuli (such as humidity, light, magnetic field, etc.) using different material combinations to achieve shape memory effect.

[0064] Example 1: Multistability and shape memory effect of a single-cell kirigami structure

[0065] This embodiment takes the rotating square unit as an example to demonstrate the multistability and shape memory effect of the single-cell kirigami structure. Figure 9 and Figure 10 As shown in Figure 2, two examples of unit cell design are given. The difference between the two unit cells is that different deformation modes are achieved by controlling the number of rotational ligaments (by controlling whether there are gaps between adjacent squares). This specifically includes two aspects:

[0066] (1) Programmable morphology at low temperatures

[0067] In a low temperature environment (such as room temperature), the shape of the single-cell kirigami structure is programmed by gradually applying external force. Specifically, the rotation of the rotation unit 2 is realized by the external force to form a temporary shape, and the boundary unit 1 composed of material A provides high rigidity support to maintain the temporary shape and complete the shape reconstruction. For example, Figure 9The stretched shape of the unit cell under the action of axial tensile external force. Figure 10 The bending deformation of the unit cell under the action of external bending force.

[0068] (2) Shape memory effect under temperature response

[0069] When the external temperature rises to a critical value (the critical temperature that causes a significant change in the elastic modulus of material A), the elastic modulus of material A decreases significantly, and the rigid support of boundary unit 1 weakens, triggering the morphological recovery of the paper-kirigami structure. It specifically includes two stages: the first stage: before the temperature reaches the glass transition temperature of material A, the elastic modulus of material A gradually decreases, the boundary constraint force gradually decreases, and the internal structure begins to transition from a temporary form to an initial form. The second stage: when the temperature reaches the glass transition temperature, the elastic modulus of material A decreases rapidly, the boundary unit 1 softens rapidly, and the entire structure returns to its original form, completing the restoration of the memory shape.

[0070] Example 2: Multistability and shape memory effect of multicellular paper-kirigami structures

[0071] Based on the first embodiment, the second embodiment shows a multi-cell paper-cut structure composed of multiple single-cell paper-cut units arranged and combined in an orderly manner. Compared with the single-cell paper-cut structure, the multi-cell paper-cut structure has richer programmable forms, such as Figure 11 As shown in Figure 1 . It also includes two processes: programmable morphology at room temperature and temperature-responsive shape recovery. However, unlike single cells, multi-cell assemblies offer greater deformation freedom and multistability, enabling local or global morphological reconstruction, such as loading processes ① to ⑤, and temperature-dependent stepwise deformation recovery (processes ⑥ and ⑦), providing richer and more interesting shape changes and functional applications.

[0072] In addition to the above-mentioned multi-cell paper-cut structure, the present invention also provides some cases that can be used for the design of expandable (contractible) structures, such as Figures 12 to 19 As shown. Among them, Figures 12 to 15 The team demonstrated two multicellular structures with two-dimensional expansion (contraction) configurations. Through the orderly arrangement and combination of multiple unit cells, a wide range of expansion and contraction functions are achieved on the plane. At room temperature, such structures can be stretched or compressed to the desired state by external forces, making them suitable for applications requiring flat coverage or protection. Furthermore, under temperature fluctuations, the structure can automatically expand or contract, thereby acting as a dynamic sunshade, providing temperature-dependent shading or light transmission adjustments. Figure 16 and Figure 17Examples of three-dimensionally expanded multicellular kirigami structures are provided, including cubic and cylindrical multicellular kirigami structures. The cubic multicellular structure has directional symmetry and can expand or contract in three dimensions under temperature changes. It is suitable for structures that need to expand or contract in all directions, such as retractable storage devices or space filling materials. The cylindrical multicellular structure has the characteristics of axial expansion and is suitable for applications such as flexible conveying pipes and telescopic support columns. For non-axial expansion, Figure 18 and Figure 19 A multicellular structure composed of rotating triangular units was demonstrated. This structure, through the geometric configuration of the rotating triangular units, can achieve more complex asymmetric morphological changes, suitable for structural requirements requiring non-axial adjustment. Under temperature stimulation, the triangular units in this structure can expand or contract through rotational deformation, resulting in highly programmable and complex morphological changes.

[0073] Example 3: Temperature alarm based on rotating square paper-cut structure unit cell

[0074] In this embodiment, a temperature alarm based on a single-cell paper-kirigami structure is designed. Figure 20 and Figure 21 As shown. Its working principle is that, first, the shape of the unit cell is reconstructed under low temperature conditions and placed in the circuit connected to the alarm in the form of a disconnected circuit. When the temperature rises (fire occurs or is close to the fire source) to the glass transition temperature of material A in the paper-cut structure, the shape memory effect of the structure is triggered, and the structure restores its initial shape to connect the circuit, thereby activating the alarm. In addition, it should be noted that the key to whether the structure triggers the shape memory effect and deforms is whether material A reaches the glass transition temperature. Therefore, the selection of material A with different glass transition temperatures can achieve customization of the alarm temperature and even the design of a graded alarm device.

[0075] Compared with traditional electronic alarms based on complex, highly integrated circuits, paper-cut temperature alarms, which focus on mechanical structures, have the following advantages: (1) Low power consumption: Traditional electronic alarms require real-time power supply to detect changes in ambient temperature, while paper-cut temperature alarms rely on the direct response of materials to temperature and do not require continuous power support. (2) Simple structure: The design of paper-cut temperature alarms is relatively simple, with low manufacturing costs and suitable for large-scale production. In comparison, the integrated circuit design and manufacturing process of electronic alarms are complex, involving multiple electronic components (such as sensors, control chips, batteries, etc.), requiring higher manufacturing precision and more complex processes. (3) High reliability and strong anti-interference ability: The paper-cut structure is based on the principle of mechanical response and is not affected by electromagnetic interference or signal interference. It is particularly suitable for environments that resist electromagnetic radiation or other electrical interference. For example, in heavy industry, steel mills or environments with high electromagnetic interference, electronic alarms may cause false alarms or failures due to external signal interference, while paper-cut alarms can maintain a stable working state due to mechanical response and have high reliability. (4) Wide operating temperature range: The paper-cut structure alarm sets the response threshold through the glass transition temperature of the material to adapt to the working requirements under extreme high temperature conditions, while traditional electronic alarms may damage the circuit or components due to the high temperature environment. The paper-cut alarm can adapt to various temperature conditions more flexibly in terms of material selection and structural design. Especially in high-temperature fires, its response is more reliable and not easy to damage. (5) Gradual alarm: The paper-cut alarm can achieve multi-level alarms at different temperatures by combining materials with different glass transition temperatures. In fire warning, the paper-cut structure can be gradually expanded according to the temperature to achieve phased and graded alarms, while traditional electronic alarms can often only set a single alarm temperature threshold or it is difficult to achieve complex graded alarm functions.

[0076] Example 4: Thrower based on rotating triangle paper-cut structure unit cell

[0077] This embodiment shows a thrower device based on a rotating triangle paper-cut structure. Figure 22 As shown. Its working process includes three main steps: (1) Accumulation of elastic potential energy (standby state): Under low temperature conditions, the paper-cut unit cell is reshaped. Due to the high rigidity constraint of the boundary unit 1, the energy stored in the shape reconstruction process is mechanically locked, thereby realizing elastic energy storage. (2) Trigger release: After the preset trigger condition is met (reaching the specified temperature), the boundary unit 1 composed of material A softens, the mechanical lock is released, the paper-cut structure is rapidly unfolded, and the stored elastic potential energy is released instantly, ejecting the object to hit the target. (3) Energy storage again: After the throwing is completed, the paper-cut structure can be restored to its initial state, and energy storage is realized again by external force loading and preparing for a second throw, realizing multiple service.

[0078] Similarly, throwers based on mechanical response also have many advantages. Specifically, they include: (1) Energy efficiency and stable properties: using the elastic potential energy of the paper-cut structure to throw objects, no complex electric drive is required, and it is suitable for outdoor or power-free environments. (2) Precise control: through the temperature trigger mechanism, the throwing time can be precisely controlled to meet the needs of emergency and unmanned operation. (3) Multiple reuse: the paper-cut structure can be restored to its original shape through temperature stimulation and allowed to be reconstructed to store energy, achieving multiple repeated throwing and improving the efficiency of the device.

[0079] Example 5: Robotic arm based on multicellular paper-kirigami structure

[0080] This embodiment shows a flexible manipulator device based on a multicellular paper-kirigami structure. Figure 23 and Figure 24 As shown. Each "finger" in the manipulator is composed of a combination of unit cells with axial and bending deformations. At room temperature, through shape reconfiguration, the manipulator can have a variety of programmable shapes, allowing the manipulator to remain stable at different angles and curvatures, thereby flexibly adjusting the opening and closing states of its "fingers" to accommodate objects of different shapes and sizes. When the manipulator needs to grasp or release an object, it can use the shape memory effect of the multi-cell kirigami structure to achieve automatic shape transformation through temperature triggering. Specifically, during the operation of the grasping manipulator, when the ambient temperature rises or reaches the glass transition temperature of material A through artificial heating, the elastic modulus of material A significantly decreases, the boundary constraints of each unit cell in the manipulator's "fingers" are weakened, and the unit cells with compressed and unbent reconfigured shapes are released, prompting each unit cell to rotate, causing the "fingers" to elongate and bend and gradually close, completing the grasping action. During the release operation of the manipulator, environmental changes cause the unit cells with stretched and bent reconfigured shapes to be released, prompting each unit cell to rotate, causing the "fingers" to return from the closed state to the initial state, completing the release action. In addition, as a type of multicellular paper-kirigami structure, the robot also has all the advantages of the above-mentioned mechanical response, which will not be elaborated here.

[0081] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A design of an environmentally aware paper-kirigami metamaterial with simplified shape memory effect, characterized by: The invention comprises a plurality of unit cells, wherein the unit cells comprise two boundary units (1) and a plurality of rotation units (2), the two boundary units (1) are arranged relative to each other, a chamber is formed between the two boundary units (1), the plurality of rotation units (2) can move inside and outside the chamber between the two boundary units (1), the two boundary units (1) and the plurality of rotation units (2) are connected to form an integral structure via a ligament assembly, the plurality of unit cells are arranged in sequence, and the adjacent boundary units (1) between each two adjacent unit cells are fixedly connected; The ligament assembly comprises a boundary ligament (3) and a rotational ligament (4); the rotational unit (2) is connected to the adjacent boundary unit (1) via the boundary ligament (3); and each two adjacent rotational units (2) are connected via the rotational ligament (4); The boundary unit (1) is made of material A, which is a material sensitive to external stimuli; the rotation unit (2) is made of material B, which is a material insensitive to external stimuli; and the elastic modulus of material A is greater than the elastic modulus of material B under initial conditions.

2. The environmentally-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 1, characterized in that: The boundary unit (1) is a frame designed with an open inner end.

3. The environmentally-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 2, characterized in that: The outer profiles of the plurality of rotating units (2) match the profile of the cavity between the two boundary units (1).

4. The environmentally-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 3, characterized in that: One end of the boundary ligament (3) is connected to the side wall of the open end of the boundary unit (1), and the other end of the boundary ligament (3) is connected to the adjacent inner corner of the adjacent rotation unit (2).

5. The environmentally-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 1, characterized in that: The plurality of rotating units (2) can rotate inside and outside the cavity of the boundary unit (1) through mechanical loading, and the plurality of rotating units (2) can rotate and return to their initial positions through external stimulation.

6. The environmentally-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 5, characterized in that: The external stimulus includes one or more of temperature, humidity, light or magnetic field.

7. The reconstruction method of a context-aware paper-kirigami metamaterial design with a simplified shape memory effect according to any one of claims 1 to 6, characterized in that: The method includes the following steps: Under initial conditions, the rotation of the rotation unit (2) is induced by mechanical loading, resulting in the shape reconstruction of the unit cell; since the elastic modulus of the material A applied to the boundary unit (1) is higher than that of the material B applied to the rotation unit (2) under initial conditions, the boundary unit (1) can provide constraints to maintain the reconstructed geometric shape, thereby realizing the programmable morphology of the unit cell; When the external stimulus input changes, the elastic modulus of the material A applied to the boundary unit (1) decreases when it reaches a critical value, causing the boundary unit (1) with material A as a component material to become soft and the constraint ability to decrease. The reconstructed rotation unit (2) will restore the shape before reconstruction to achieve a shape memory effect.

8. The reconstruction method of the environment-aware paper-kirigami metamaterial design with simplified shape memory effect according to claim 7, characterized in that: The mechanical loading includes one or more of tension, compression or bending.

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