A switchable functional multi-stable nested composite dot matrix structure

Abstract

The present application relates to the technical field of new materials, and discloses a multi-stable nested composite lattice structure with switchable functions, which comprises a conversion unit and a bearing unit connected with the conversion unit, and the conversion unit and the bearing unit are arranged in extension in x, y and z directions to form a composite lattice structure. The multi-stable nested composite lattice structure is composed of the conversion unit and the bearing unit, the conversion unit provides a function switching component based on multi-stable geometry, so that the structure can have the function of a flexible body in one stable state to realize integrated vibration isolation and buffering, and have the function of a rigid body in another stable state to realize integrated bearing and energy absorption. The multi-stable structure and the bearing unit adopt a mutual nesting form, which expands the design range of the multi-stable structure and avoids jumping from one stable state to another stable state under load.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new materials, and particularly relates to a multi-stable nested composite lattice structure with switchable functions. BACKGROUND

[0002] In today's society, the development of lightweight materials and structures is driving the boundaries of human activities at an unprecedented speed, not only showing great potential in environmental protection, but also achieving a qualitative leap in improving the performance of engineering structures. On the one hand, by using lightweight materials such as high-performance alloys, advanced composite materials and innovative concrete, energy consumption and carbon emissions are effectively reduced, which contributes to sustainable development. On the other hand, lightweight structure design, with its excellent specific strength and specific stiffness characteristics, not only enhances the load-carrying capacity of the structure, but also significantly improves the safety performance, making grand buildings such as high-rise buildings and long-span bridges possible, greatly expanding the living and working space of human beings.

[0003] Because the lattice geometry design corresponding to different functions is quite different, the direct consolidation between multiple lattice units will obviously affect the realization of one or more functions, and there is also mutual contradiction between multiple functions. For example, there is a contradiction between vibration reduction / damping and load bearing. The design strategy of low stiffness helps to reduce the vibration of the device, but weakens the ability of the structure to resist deformation and load bearing. On the other hand, high stiffness often brings high load bearing, deformation stability and reliability, but is not conducive to the dissipation of vibration energy. How to design high-performance multifunctional lightweight materials and structures is a hot topic of widespread concern.

[0004] In recent years, structures with multi-stable performance have received continuous attention from academia and industry. Multi-stable structures, a class of structures with multiple stable states, can maintain multiple stable states under different external conditions (such as force, temperature, magnetic field, etc.). This characteristic enables them to switch functions in different application scenarios. For example, they can be used for vibration reduction and cushioning in a flexible state, and for load bearing and energy absorption in a rigid state. By designing different structural units and arrangement methods, multi-stable metamaterials can achieve a wide range of mechanical performance adjustment. This enables them to maintain excellent performance under various extreme conditions and have wide application prospects in aerospace, automotive and construction fields. These advantages make multi-stable design a key candidate for lightweight multifunctional material design. Taking a typical bistable structure as an example, based on the different performance of the two stable states, function switching is achieved through stable state switching, thereby realizing multifunctional and multi-scenario applications.

[0005] However, the current implementation of multi-stable structures is highly dependent on geometric configuration, with a small stable state space, and a large structure size is required to achieve multi-stability, which is difficult to meet the requirements of lightweight. Therefore, it is necessary to expand the design ideas of multi-stable structures. SUMMARY

[0006] In order to solve the problems in the prior art, the application provides a multi-stable nested composite lattice structure with switchable functions, which is composed of a conversion unit and a bearing unit, the conversion unit provides a function switching component based on a multi-stable geometry, so that the structure can have a flexible body function in one stable state to realize integrated vibration isolation and buffering, and can have a rigid body function in another stable state to realize integrated bearing and energy absorption, the multi-stable structure and the bearing unit are in a nested form, which expands the design range of the multi-stable structure and avoids jumping from one stable state to another stable state under load.

[0007] In order to achieve the above-mentioned purpose, the application is implemented by the following technical scheme:

[0008] The multi-stable nested composite lattice structure with switchable functions comprises a conversion unit and a bearing unit connected with the conversion unit, and the conversion unit and the bearing unit are arranged in extension in x, y and z directions to form a composite lattice structure.

[0009] The conversion unit comprises a multi-stable structure and a frame wrapped outside the multi-stable structure.

[0010] The bearing unit comprises a cubic square frame and a face-centered diagonal member.

[0011] The cubic square frame of the bearing unit has the same shape as the frame of the conversion unit.

[0012] The conversion unit and the bearing unit are connected through a connection point of a vertex of the multi-stable structure and a center of the face-centered diagonal member.

[0013] Further, the multi-stable structure comprises at least two sub-stable state structure units, and the sub-stable state structure units are perpendicular to each other and intersect at a point at the top.

[0014] Further, the sub-stable state structure unit comprises a horizontal rod, vertical rods are arranged at both ends of the horizontal rod in the same direction, inclined rods are arranged at the ends of the vertical rods, respectively, and the two inclined rods intersect at a point.

[0015] Further, the length of the horizontal rod is l1, the thickness of the vertical rod is t1, the thickness of the inclined rod is t0, the height of the inclined rod to the intersection point is h0, and the shape of the multi-stable structure is determined by l1, t1, t0 and h0.

[0016] Further, the multi-stable structure of one face of the conversion unit not connected with the bearing unit is embedded inside the frame.

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

[0018] 1. The present application is combined by a switching unit and a bearing unit, the switching unit provides a function switching component based on a multi-stable geometry, so that the structure can have a flexible body function in one stable state, realizing integrated vibration isolation and buffering; and has the function of a rigid body in another stable state, realizing integrated bearing and energy absorption, the multi-stable structure and the bearing unit adopt a nested form, which expands the design range of the multi-stable state and avoids jumping from one stable state to another stable state under load.

[0019] 2. The present application comprehensively considers the mutual switching of multiple functions such as vibration isolation, buffering, bearing and energy absorption, fully considers the feasibility of additive manufacturing, and realizes the application requirements of multi-scene, multi-object and multi-target rapid switching; the structure has a complete performance control strategy, different functions can be designed independently, the geometric design of the switching unit and the bearing unit has a large control space, which meets the multi-performance application requirements, has high adaptability, and overcomes the isolated corresponding limitations of single structure and single function.

[0020] 3. Based on the structure, a multifunctional integrated lightweight structure material with excellent performance such as high adaptability, high reliability, high portability and reusability can be designed, which has a very important application prospect in the fields of rescue, building of buildings and transportation. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the switching process of the block-shaped nested composite lattice structure of the present application; Figure 1 Figure 2 is a schematic diagram of the switching process of the strip-shaped nested composite lattice structure of the present application;

[0022] Figure 3 is a schematic diagram of the switching process of the block-shaped nested composite lattice structure of the present application; Figure 2 Figure 4 is a schematic diagram of the switching process of the strip-shaped nested composite lattice structure of the present application;

[0023] Figure 5 is a schematic diagram of the switching process of the block-shaped nested composite lattice structure of the present application; Figure 3 Figure 6 is a schematic diagram of the switching process of the strip-shaped nested composite lattice structure of the present application;

[0024] Figure 7 is a schematic diagram of the switching process of the block-shaped nested composite lattice structure of the present application; Figure 4 Figure 8 is a schematic diagram of the switching process of the strip-shaped nested composite lattice structure of the present application;

[0025] Figure 5 Figure 9 is a schematic diagram of the connection of four different forms of bearing units and switching units. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. In addition, it should be understood that those skilled in the art can make various modifications or modifications to the present application after reading the content taught by the present application, and these equivalent forms also fall within the scope defined by the present application.

[0027] This invention proposes a switchable multistable nested composite lattice structure. The designed switchable lattice structure is composed of switching units and load-bearing units. The switching units provide functional switching components based on multistable geometry, enabling the structure to function as a flexible body in one steady state, achieving integrated vibration isolation and buffering; and as a rigid body in another steady state, achieving integrated load-bearing and energy absorption. The multistable structure and load-bearing units are nested together, expanding the design range of multistable states and avoiding jumps from one steady state to another under load. The lattice structure is a three-dimensional geometric structure composed of repeating cells, typically consisting of nodes and rods connecting these nodes. They possess high geometric complexity and optimized topology. Face-centered cubic lattice structure: A face-centered cubic lattice structure is a lattice structure connecting the center of each face to each vertex.

[0028] Specifically, such as Figures 1-2 As shown, a multi-stable nested composite lattice structure with switchable functions includes a conversion unit 2 and a support unit 3 connected to the conversion unit 2. The conversion unit 2 and the support unit 3 are extended and arranged in the x, y, and z directions to form a composite lattice structure.

[0029] The conversion unit 2 includes a multistable structure 1 and a frame 2-2 enclosing the multistable structure 1 to fix the multistable structure. Figures 1-4 This is merely one feasible design pattern; the frame 2-2 can be a tetrahedron, square prism, hexagonal prism, octahedron, or dodecahedron, etc. The multistable structure 1 includes two sub-stable structure units 1-2, which are perpendicular to each other and intersect at vertex 1-1. Each sub-stable structure unit 1-2 includes a horizontal bar, with vertical bars perpendicularly arranged at both ends of the horizontal bar. Diagonal bars are respectively provided at the ends of the two vertical bars, and the two diagonal bars intersect at a single point. The length of the horizontal bar is l1, the thickness of the vertical bar is t1, the thickness of the diagonal bar is t0, and the height of the diagonal bar to the intersection point is h0. The shape of the multistable structure 1 is determined by l1, t1, t0, and h0.

[0030] The supporting unit 3 includes a cubic frame 3-2 and a face-center diagonal member 3-3; the shape of the cubic frame 3-2 of the supporting unit 3 is the same as the shape of the frame 2-2 of the conversion unit 2; the cubic frame 3-2 can also have various shapes. Figure 1 This is just one type of cubic load-bearing unit composed of a cubic frame and diagonally opposite face members. (Attached) Figures 1-4Only one design mode can be implemented, the carrier can be composed of cubic frame and face center diagonal member, cubic frame and body center diagonal member, face center diagonal member, body center diagonal member, etc. The center connection point 3-1 of each face of the carrier unit is connected with the vertex 1-1 of the multi-stable structure 1. Thus a basic unit composed of a conversion unit and a carrier unit is formed, as shown in Figure 2 Each conversion unit and carrier unit has six connection points, so an infinite array in three-dimensional space can be realized to meet the application requirements of various scales. Specifically, the conversion unit 2 and the carrier unit 3 are connected through the vertex 1-1 of the multi-stable structure 1 and the center connection point 3-1 of the face center diagonal member 3-3.

[0031] When the carrier function is needed, that is, high stiffness and high strength are needed, the multi-stable structure 1 of one side of the conversion unit 2 not connected with the carrier unit 3 is embedded inside the frame 2-2.

[0032] From the perspective of function switching, this design can realize the switching between flexible state and rigid state. For the flexible state shown on the left, Figure 2 The function is mainly determined by the multi-stable structure of the conversion unit. In this state, the conversion unit and the carrier unit are only connected through the multi-stable structure, and the overall stiffness and strength performance of the multi-stable structure is low, and the deformation is strong, which can realize flexible functions such as vibration reduction, vibration isolation and buffering according to the requirements of working conditions. These performances can be adjusted by adjusting the related geometric parameters of the multi-stable structure. By applying external force and other methods, the multi-stable structure produces large deformation and enters another stable state. This stable state can still be maintained after the external load is removed, and the load for realizing stable state transition can be changed according to different materials, such as applying external force, changing environmental temperature, magnetic field environment, etc. After the stable state conversion, the design scheme proposed in this patent enables the multi-stable structure to be embedded into the carrier unit, the main purpose of which is to ensure the docking accuracy and stable state maintenance. This nesting method avoids the situation that the non-deformation part of the multi-stable structure is insufficient in stiffness during the pressing process, which leads to the lack of stable state, so as to overcome the limitations of the conventional multi-stable structure design. After the stable state conversion, the peripheral frame of the conversion unit contacts with the carrier unit, and the overall stiffness and strength of the structure are greatly improved, so it has high carrying capacity and energy absorption capacity. The performance of this part is determined by the carrier unit and the non-stable execution component of the conversion unit. The two stable state switching processes realize the function switching, so as to have the effect of integrated vibration reduction, isolation, buffering, carrying and energy absorption.

[0033] Embodiment 1: The embodiment provides a block-shaped nested composite lattice structure

[0034] As shown in Figure 3The diagram presents a block-shaped nested composite lattice structure, consisting of a 3×3×3 array of 27 cubic lattice cells, with 14 conversion units 2 and 13 load-bearing units 3 arranged in the array. Each conversion unit comprises 6 multistable structures. In the flexible functional state, the conversion units and load-bearing units are connected only through the multistable structures. These multistable structures have relatively low overall stiffness and strength, but high deformability, and can perform flexible functions such as vibration reduction, vibration isolation, and buffering according to the requirements of the working conditions. Therefore, the designed composite nested lattice structure can effectively prevent the protected object from harmful effects such as vibration. Simultaneously, due to the relatively low stiffness and strength of the multistable structures, the buffering effect on brittle objects (such as eggs) is more effective in the flexible state. After applying a certain load, the multistable structure enters another stable state. Due to this new stable state, the outer frame of the conversion unit contacts the load-bearing unit, significantly improving the overall stiffness and strength of the structure, thus exhibiting high load-bearing capacity and energy absorption capacity. Therefore, in the rigid state, the designed composite nested lattice can effectively support the protected object above. Meanwhile, the rigid structure is more effective at cushioning heavy / hard objects (such as iron blocks). This block-like nested composite lattice structure has great application potential in protective devices for transportation vehicles and the construction of large-scale stabilization platforms.

[0035] Example 2: This example provides a strip-shaped nested composite lattice structure.

[0036] like Figure 4 The strip-shaped nested composite lattice structure shown consists of 10 units, arranged as 5 conversion units 2 and 5 load-bearing units 3. In the flexible state, the conversion units and load-bearing units are connected only through a multistable structure. The multistable structure has low overall stiffness and strength but high deformation capacity; a small load at the midpoint of the span can achieve a large deflection. In this state, flexible functions such as vibration reduction and buffering are achieved according to the requirements of the working conditions, such as buffering brittle objects (e.g., eggs). After applying a certain load, the multistable structure enters another stable state. Due to the new stable state, the outer frame of the conversion unit and the load-bearing unit come into contact, and the overall stiffness and strength of the structure are greatly improved. In the rigid state, a large load must be applied at the midpoint of the span to achieve a large deflection, which can be used for bearing / buffering heavy / hard objects. The strip-shaped composite nested lattice structure can be stowed in the flexible state and can achieve unsupported large-span load-bearing in the rigid state, showing great application potential in the rigid-flexible operation of robotic arms, disaster relief and rescue, and bridge construction.

[0037] The switchable multi-stable nested composite lattice structure design scheme comprehensively considers the mutual switching of multiple functions of vibration reduction / isolation, buffering, bearing, and energy absorption, fully considers the feasibility of additive manufacturing, and realizes the application requirements of multi-scene, multi-object, and multi-target rapid switching. The proposed switchable multi-stable nested composite lattice structure design scheme has a complete performance regulation strategy, different functions can be independently designed, the geometric design of the switching unit and the bearing unit has a large regulation space, and the application requirements of multiple performances are met. The proposed structure design scheme has high adaptability, and overcomes the isolated corresponding limitation of single structure and single function.

[0038] In the actual process, the required functions can be summarized according to one or more specified working conditions, customized design is realized according to the required functions, and the feasibility of the preparation process and function realization of the designed composite lattice structure is analyzed. If they are all met, the design is completed and enters the preparation and production link; if not, it is returned to the customized design stage and iteratively designed and verified. According to the use requirements of multiple scenes, there is a large controllable range.

[0039] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change within the technical range disclosed by the present application according to the technical scheme and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A switchable functional multi-stable nested compound lattice structure, characterized in that: The application relates to a composite lattice structure, which comprises a conversion unit (2) and a bearing unit (3) connected with the conversion unit (2), wherein the conversion unit (2) and the bearing unit (3) are arranged in extension in x, y and z directions to form the composite lattice structure. The conversion unit (2) comprises a multi-stable structure (1) and a frame (2-2) wrapped outside the multi-stable structure (1); the bearing unit (3) comprises a cubic frame (3-2) and a face-centered diagonal component (3-3); the shape of the cubic frame (3-2) of the bearing unit (3) is the same as that of the frame (2-2) of the conversion unit (2); the conversion unit (2) and the bearing unit (3) are connected through a vertex (1-1) of the multi-stable structure (1) and a center connecting point (3-1) of the face-centered diagonal component (3-3); The multi-stable structure (1) comprises two sub-stable structure units (1-2), and the two sub-stable structure units are perpendicular to each other and intersect at the vertex (1-1) at the top. The sub-stable structure unit (1-2) comprises a horizontal rod, vertical rods arranged in the same direction at both ends of the horizontal rod, and inclined rods arranged at the ends of the vertical rods respectively, and the two inclined rods intersect at a point.

2. The switchable functional multi-stable nested complex lattice structure according to claim 1, wherein: The length of the horizontal rod is l1, the thickness of the vertical rod is t1, the thickness of the inclined rod is t0, the height of the inclined rod to the intersection point is h0, and the shape of the multi-stable structure (1) is determined by l1, t1, t0 and h0.

3. The switchable functional multi-stable nested composite plasmonic lattice structure of claim 1, wherein: The multi-stable structure (1) of one side of the conversion unit (2) not connected with the bearing unit (3) is embedded in the frame (2-2).

Images