Variable stiffness metamaterial and working method thereof

Abstract

According to the variable-stiffness metamaterial and the working method thereof, the variable-stiffness metamaterial comprises the bistable unit and the active control unit, the bistable unit is composed of the elastic structure, the elastic structure can be converted between two stable geometric configurations under different triggering conditions and has different stiffness characteristics in a stable state, and the active control unit is connected with the bistable unit. The active control unit can drive the bistable unit to be converted between two stable geometric configurations, and according to the variable-rigidity metamaterial provided by the invention, through accurate driving of the active control unit, state conversion of the bistable unit can be quickly realized, so that quick adjustment of the rigidity of the material is realized, and the rigidity of the material is improved. And certain application requirements sensitive to time, such as automobile collision protection, mechanical vibration control and the like, are met.

Description

Technical Field

[0001] The present application relates to the technical field of metamaterials, and in particular to a variable stiffness metamaterial and a working method thereof. Background Art

[0002] In many engineering and technological applications, there are diverse requirements for the stiffness properties of materials. The stiffness of traditional materials is usually fixed, which has great limitations in some scenarios where the structural performance needs to be flexibly adjusted according to different working conditions. For example, in aerospace structures, different flight phases (such as takeoff, cruising, and landing) have different requirements for the stiffness of the structure; in automobile collision safety design, it is expected that the material will maintain a certain flexibility during normal driving to provide comfort, and rapidly increase the stiffness at the moment of collision to provide better protection; in the biomedical field, materials implanted in the human body sometimes need to adjust the stiffness according to the body's movement state and stress conditions to achieve better adaptability and safety. Existing variable stiffness materials mostly use passive adjustment methods, such as changing the stiffness of the material through environmental factors such as temperature and humidity, but these methods are insufficient in adjustment speed, range, and accuracy, and lack active control capabilities.

[0003] Therefore, it is necessary to develop a new metamaterial with active stiffness adjustment characteristics and better performance. Summary of the invention

[0004] In view of this, the present invention provides a variable stiffness metamaterial and a working method thereof to overcome the shortcomings of existing variable stiffness materials such as slow adjustment speed, narrow range, low precision and lack of active control capability, and to achieve fast, precise, wide range and active control of material stiffness to meet the complex and varied engineering and application requirements in different fields.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] One of the purposes of this application is to provide a variable stiffness metamaterial, comprising:

[0007] A bistable unit, the bistable unit being composed of an elastic structure that can switch between two stable geometric configurations under different triggering conditions and having different stiffness characteristics in the stable state; and

[0008] An active control unit is connected to the bistable unit, and the active control unit can drive the bistable unit to switch between two stable geometric configurations.

[0009] In some of the embodiments, the elastic structure includes a thin plate, a rod structure or a micro-nano structure with pre-deformation.

[0010] In some of the embodiments, the active control unit includes a sensor, a controller and a driver. The sensor is used to sense external environmental information or receive external control instructions. The controller generates a driving signal based on the external environmental information or external instructions fed back by the sensor. The driver drives the state conversion of the bistable unit based on the driving signal.

[0011] In some of the embodiments, the external environment information includes stress or strain or temperature or electric field or magnetic field.

[0012] In some of the embodiments, the actuator is a driving device based on electromagnetic, piezoelectric, shape memory alloy, electrostatic hydraulic or other effects.

[0013] In some of the embodiments, a base material is further included, wherein the base material is used to support and carry the bistable unit.

[0014] In some embodiments, the matrix material includes polymer, metal, ceramic or composite material.

[0015] The second object of the present application is to provide a working method of the variable stiffness metamaterial, comprising the following steps:

[0016] The active control unit drives the bistable unit to switch between two stable geometric configurations according to external environmental information or external control instructions, and has different stiffness characteristics in a stable state.

[0017] This application adopts the above technical solution, and its beneficial effects are as follows:

[0018] The variable stiffness metamaterial and its working method provided by the present application include a bistable unit and an active control unit. The bistable unit is composed of an elastic structure. The elastic structure can be converted between two stable geometric configurations under different triggering conditions and has different stiffness characteristics in a stable state. The active control unit can drive the bistable unit to convert between the two stable geometric configurations. The variable stiffness metamaterial provided by the present application can quickly realize the state conversion of the bistable unit through the precise driving of the active control unit, thereby realizing rapid adjustment of the material stiffness and meeting some time-sensitive application requirements, such as automobile collision protection, mechanical vibration control, etc.

[0019] The variable stiffness metamaterial and its working method provided by the present application, the active control unit includes a sensor, a controller and a driver, the sensor is used to sense external environmental information or receive external control instructions, the controller generates a driving signal according to the external environmental information or external instructions fed back by the sensor, and the driver drives the state conversion of the bistable unit according to the driving signal. The present application utilizes the precise feedback of the sensor and the intelligent algorithm of the controller to accurately control the change in material stiffness, and can adjust the stiffness to the required precise value according to different working conditions and requirements, thereby improving the adaptability and performance of the material under various complex working conditions.

[0020] The variable stiffness metamaterial and its working method provided by the present application can achieve a wide range of stiffness adjustment and a leap-forward transition from a relatively soft state to a relatively rigid state, since the bistable unit has significantly different stiffness characteristics in different stable states, and is suitable for a variety of application scenarios from flexible structures to rigid structures.

[0021] The variable stiffness metamaterial and its working method provided in the present application can actively adjust the stiffness of the material according to real-time changes in the external environment or active instructions of the user, rather than relying on passive environmental factors, which greatly expands the application flexibility and applicability of the material and can be used in various occasions that require dynamic adjustment of structural performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a schematic diagram of the rigid support structure in the bistable unit of the present invention;

[0024] Figure 2 It is a schematic diagram of the elastic structure (laser cutting diagram) in the bistable unit of the present invention;

[0025] Figure 3 This is a schematic diagram of the first stable state of the metamaterial unit cell of the present invention;

[0026] Figure 4 This is a schematic diagram of the second stable state of the metamaterial unit cell of the present invention;

[0027] Figure 5 This is a schematic diagram of the first stable state of the metamaterial unit cells connected in series in one direction (x direction) according to the present invention;

[0028] Figure 6This is a schematic diagram of the second stable state of the metamaterial unit cells connected in series in one direction (x direction) according to the present invention;

[0029] Figure 7 This is a schematic diagram of the bidirectional (x and y directions) series connection structure of the metamaterial unit cell of the present invention;

[0030] Figure 8 It is a schematic diagram of the three-dimensional (x, y, and z directions) series structure of the metamaterial unit cell of the present invention. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0032] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0033] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0034] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0035] See also Figure 1 and Figure 2 , is a schematic diagram of the structure of the variable stiffness metamaterial provided by the embodiment of the present application, including a bistable unit 100 and an active control unit 200. The technical solution for its implementation is described in detail below.

[0036] In this embodiment, the bistable unit 100 can switch between two stable geometric configurations under different triggering conditions, and has different stiffness characteristics in the stable state, such as Figure 1 The A state is one of the stable geometric configurations, and the B state is another stable geometric configuration. It switches between the A state and the B state under different triggering conditions, and has different stiffness characteristics in the A state and the B state.

[0037] In this embodiment, the active control unit 200 is connected to the bistable unit 100 , and the active control unit 200 can drive the bistable unit 100 to switch between two stable geometric configurations.

[0038] See also Figure 3 The bistable unit 100 is composed of an elastic structure 110, which can be switched between two stable geometric configurations under different triggering conditions and has different stiffness characteristics in a stable state, such as Figure 4 Schematic diagram of the rigid support structure 120 in a bistable unit in a stable state.

[0039] It should be noted that the bistable unit 100 is composed of elastic structures, which have two stable geometric configurations and can switch between the two stable states under different triggering conditions. This bistable property is the basis for realizing the change of material stiffness. By changing the state of the bistable unit, the overall stiffness of the material can be significantly changed.

[0040] See also Figures 5 to 8 The bistable unit 100 can be implemented in various forms, such as by elastic components of specific shapes (for example, thin plates with pre-deformation, rod structures or micro-nano structures, etc.), which can be transformed from one stable state to another stable state under force or other external excitations, and have different stiffness characteristics in the stable state.

[0041] It can be understood that the variable stiffness metamaterial provided in this embodiment has significantly different stiffness characteristics in different stable states. Therefore, the metamaterial of the present invention can achieve a wide range of stiffness adjustment, and can achieve a leap from a relatively soft state to a relatively rigid state. It is suitable for a variety of application scenarios from flexible structures to rigid structures, and can achieve a wide range of adjustment.

[0042] The active control unit 200 is connected to the bistable unit 100 , and the active control unit 200 can drive the bistable unit 100 to switch between two stable geometric configurations.

[0043] In this embodiment, the active control unit 200 includes a sensor, a controller and a driver. The sensor is used to sense external environmental information (such as stress, strain, temperature, electric field, magnetic field, etc.) or receive external control instructions. The controller determines the driving signal for the bistable unit through a preset algorithm based on the information fed back by the sensor or the external instruction, and the driver is responsible for driving the state conversion of the bistable unit 100 according to the driving signal.

[0044] Specifically, the driver can be a driving device based on electromagnetic, piezoelectric, shape memory alloy, electrostatic (hydraulic) or other effects, which is selected and designed according to different application scenarios and requirements to achieve fast and precise driving of the bistable unit.

[0045] It can be understood that the variable stiffness metamaterial provided in this embodiment can actively adjust the stiffness of the material according to real-time changes in the external environment or active instructions of the user, rather than relying on passive environmental factors, which greatly expands the application flexibility and applicability of the material and can be used in various occasions that require dynamic adjustment of structural performance.

[0046] In this embodiment, the variable stiffness metamaterial further includes a matrix material. The matrix material, as a medium for supporting and carrying the bistable units, plays a role in protecting and connecting the bistable units, and also has a certain influence on the overall performance of the material.

[0047] Furthermore, the matrix material may be a polymer, a metal, a ceramic or a composite material, and a suitable matrix material is selected according to specific application requirements to ensure its compatibility and cooperative working ability with the bistable unit.

[0048] For example, the matrix material can be carbon fiber, Kevlar, fiberglass, aluminum alloy, 3D printing metal, PLA, ABS, etc.

[0049] The present application also provides a working method of a variable stiffness metamaterial, comprising the following steps: the active control unit 200 can drive the bistable unit 100 to switch between two stable geometric configurations according to external environmental information or external control instructions, and have different stiffness characteristics in a stable state.

[0050] The variable stiffness metamaterial and its working method provided by the above embodiment of the present application are composed of a bistable unit, an active control unit and a matrix material. The bistable unit is the core, and its structure has two stable geometric configurations, which can switch states under different trigger conditions, laying the foundation for stiffness changes. The active control unit includes a sensor, a controller and a driver. The sensor senses external environmental information or receives instructions, and the controller controls the driver through a preset algorithm accordingly, and the driver drives the state conversion of the bistable unit. The matrix material is used to carry and connect the bistable unit. This metamaterial overcomes the shortcomings of the existing variable stiffness materials, such as slow adjustment speed, narrow range, low precision and lack of active control ability, and can achieve fast, accurate, wide range and active adjustment of material stiffness, and is suitable for many fields such as active health medical equipment, aerospace, automobile industry, machinery manufacturing, construction engineering, biomedicine and intelligent structure. There are various application examples in different fields, such as different flight stages of wings in aerospace, state adjustment of bumpers and frames in the automotive industry during driving and collision, and adaptation of implanted structures to human activities in biomedicine, etc., which provide innovative solutions for dynamic adjustment of structural performance in various fields, showing broad application prospects and important practical value.

[0051] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A variable stiffness metamaterial, characterized in that: include: A bistable unit, the bistable unit being composed of an elastic structure that can be switched between two stable geometric configurations under different triggering conditions and having different stiffness characteristics in the stable state; and An active control unit is connected to the bistable unit, and the active control unit can drive the bistable unit to switch between two stable geometric configurations.

2. The variable stiffness metamaterial according to claim 1, characterized in that: The elastic structure includes a pre-deformed thin plate, a rod structure or a micro-nano structure.

3. The variable stiffness metamaterial according to claim 1, characterized in that: The active control unit includes a sensor, a controller and a driver. The sensor is used to sense external environmental information or receive external control instructions. The controller generates a driving signal according to the external environmental information or external instructions fed back by the sensor. The driver drives the state conversion of the bistable unit according to the driving signal.

4. The variable stiffness metamaterial according to claim 3, characterized in that: The external environment information includes stress or strain or temperature or electric field or magnetic field.

5. The variable stiffness metamaterial according to claim 3, characterized in that: The driver is a driving device based on electromagnetic, piezoelectric, shape memory alloy, electrostatic hydraulic or other effects.

6. The variable stiffness metamaterial according to claim 1, characterized in that: Also included is a base material, which is used to support and carry the bistable unit.

7. The variable stiffness metamaterial according to claim 6, characterized in that: The matrix material includes polymer, metal, ceramic or composite material.

8. A method for operating the variable stiffness metamaterial as claimed in claim 1, characterized in that: The steps include: The active control unit drives the bistable unit to switch between two stable geometric configurations according to external environmental information or external control instructions, and has different stiffness characteristics in a stable state.

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