Negative poisson's ratio tubular structures for energy absorption and methods of manufacture

Abstract

Disclosed are a negative Poisson's ratio tubular structure for buffering energy absorption and a manufacturing method, the negative Poisson's ratio tubular structure for buffering energy absorption is a tubular structure with a bidirectional reentrant cross section, four inner concave sharp corners of a four-corner star-shaped structure are replaced by four inner concave linear connection structures to obtain a bidirectional reentrant cross section, and holes are periodically and uniformly distributed in the transverse direction and the longitudinal direction of the tubular structure, the distance between adjacent holes is less than the wall thickness of the tubular structure, so that the tubular structure first appears hole collapse in the process of axial compression, and the tubular structure has a negative Poisson's ratio characteristic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of buffering and energy absorption, and particularly relates to a negative Poisson's ratio tubular structure for buffering and energy absorption and a manufacturing method. BACKGROUND

[0002] Impacts exist widely in the fields of traffic equipment, aerospace, marine equipment, etc., which pose a great threat to human safety and equipment reliability. Efficient and safe anti-impact and buffering and energy absorption devices have always been a hot research topic. Thin-walled tubular structures are energy absorption devices with simple structures, which are widely used in various anti-impact fields due to their simple structure, light weight, high energy absorption efficiency, simple manufacturing, and low cost. However, when the thin-walled tubular structure is subjected to axial compression, it expands transversely, and the peak stress is large. When the force bearing capacity of the protected object is limited, the protection and buffering will fail. In the case of limited space, the thin-walled tubular structure cannot deform smoothly, resulting in no buffering effect. Negative Poisson's ratio superstructures with the unconventional characteristics of tensile expansion and compressive contraction have great application potential in the field of buffering and energy absorption. However, most of the current research results are mainly concentrated in two-dimensional negative Poisson's ratio structures and three-dimensional negative Poisson's ratio structures with complex spatial configurations. In practical applications, three-dimensional negative Poisson's ratio structures have higher application value, but there are still few three-dimensional negative Poisson's ratio structures that can be practically applied. Although three-dimensional negative Poisson's ratio structures have excellent energy absorption capacity and buffering effect, the complex spatial configuration determines that they can only be processed and formed by means of additive manufacturing. The high cost, low efficiency, and low quality of manufacturing greatly restrict the application of negative Poisson's ratio structures in the field of buffering and energy absorption.

[0003] The information disclosed in the background section merely serves to enhance the understanding of the background of the present application, and therefore can include information that does not constitute prior art that is already known to those of ordinary skill in the art. SUMMARY

[0004] In view of the deficiencies or defects in the prior art, a negative Poisson's ratio tubular structure for buffering and energy absorption and a manufacturing method are provided, which are simple to manufacture and have a low peak stress, solving the problems of large peak stress of existing tubular structures and difficult manufacturing, high cost, and low efficiency of three-dimensional negative Poisson's ratio structures.

[0005] The purpose of the present application is achieved by the following technical solutions.

[0006] The negative Poisson's ratio tubular structure for buffering energy absorption is a tubular structure with a cross section of a bidirectional reentrant configuration, four inner concave sharp corners of a four-corner star-shaped structure are replaced by four inner concave linear connection structures to obtain a cross section of a bidirectional reentrant configuration, and the tubular structure is periodically and uniformly distributed with holes in the transverse and longitudinal directions, and the distance between adjacent holes is less than the wall thickness of the tubular structure, so that the tubular structure first appears hole collapse during axial compression, so that the tubular structure has a negative Poisson's ratio characteristic.

[0007] In the negative Poisson's ratio tubular structure for buffering energy absorption, the linear connection structure is disconnected and serves as a rivet connection to decompose the tubular structure with a cross section of a bidirectional reentrant configuration into four identical pre-bent perforated plates, and the negative Poisson's ratio tubular structure for buffering energy absorption is assembled from the four pre-bent perforated plates and rivets.

[0008] In the negative Poisson's ratio tubular structure for buffering energy absorption, the pre-bent perforated plate includes a corner structure of a four-corner star-shaped structure, the corner structure has a first plate and a second plate bent at a predetermined angle with the first plate, the first plate is bent at an end to form a linear plate of a linear connection structure, and the second plate is bent at an end to form a linear plate of another linear connection structure.

[0009] In the negative Poisson's ratio tubular structure for buffering energy absorption, a connecting rib is provided at the bent portion of the second plate and the first plate.

[0010] In the negative Poisson's ratio tubular structure for buffering energy absorption, the rivet connection of the linear plate is provided with a reserved hole for connecting the rivet, and the linear plates of the adjacent linear connection structures are connected by rivets based on the reserved hole after the pre-bent perforated plates are combined to form a negative Poisson's ratio tubular structure for buffering energy absorption with a cross section of a bidirectional reentrant configuration.

[0011] In the negative Poisson's ratio tubular structure for buffering energy absorption, the pre-bent perforated plate is a stainless steel flat plate.

[0012] In the negative Poisson's ratio tubular structure for buffering energy absorption, the long axis and the short axis of the adjacent holes are orthogonal.

[0013] In the negative Poisson's ratio tubular structure for buffering energy absorption, the hole shape includes an ellipse, a rhombus, or a hexagon.

[0014] In the negative Poisson's ratio tubular structure for buffering energy absorption, the negative Poisson's ratio tubular structure for buffering energy absorption is a symmetrical structure.

[0015] The manufacturing method of the negative Poisson's ratio tubular structure for buffering energy absorption includes the following steps,

[0016] According to the overall size and the cross-sectional size of the negative Poisson's ratio tubular structure for buffering and energy absorption, the size of the pre-bent perforated plate is obtained, and according to the overall size, Poisson's ratio and response stress level of the negative Poisson's ratio tubular structure for buffering and energy absorption, the hole size on the pre-bent perforated plate and the distance between adjacent holes are obtained,

[0017] According to the size of the pre-bent perforated plate and the hole size on the pre-bent perforated plate and the distance between adjacent holes, the pre-perforated plate is cut by laser cutting or die cutting on a flat plate, and the pre-bent perforated plate is bent at a predetermined angle at a predetermined bending position to obtain four pre-bent perforated plates,

[0018] The pre-bent perforated plates are combined in staggered arrangement, the rivet holes are aligned for riveting, and the tubular structure with a bidirectional reentrant configuration in the cross section is obtained.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] In the axial compression, the present application forms a plastic hinge at the connection of the elliptical hole, replaces the yield and buckling of the tubular structure, reduces the peak stress of the tubular structure in the buffering process, and improves the safety of the protected object; by uniformly arranging the orthogonal elliptical holes on the plate, the tubular structure presents a transverse contraction phenomenon in the axial compression, so that the structure has a negative Poisson's ratio characteristic, and the application scene of the tubular buffering structure which originally produces transverse expansion in the axial compression is widened to the engineering scene with limited space; the base material of the present application is a plate, and various sizes of negative Poisson's ratio tubular structures for buffering and energy absorption can be customized within the processing allowable range, and negative Poisson's ratio buffering tubes of any size can be designed and manufactured according to different application conditions; by laser cutting, die forming, combination assembly and riveting, a 3D negative Poisson's ratio tubular structure for buffering and energy absorption with a complex cross-sectional configuration is manufactured, the present application scheme is reasonable, simple to manufacture, low in cost, and can mass-produce 3D negative Poisson's ratio buffering devices.

[0021] The description is only a summary of the technical scheme of the present application, in order to make the technical means of the present application more clear and understandable, to the extent that the content of the description can be implemented by the person skilled in the art, and in order to make the said and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are exemplified below. BRIEF DESCRIPTION OF DRAWINGS

[0022] Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiment. The accompanying drawings are included to provide a better understanding of the preferred embodiment, and are not intended to limit the scope of the application. It should be readily understood that the drawings are not to scale, and are merely intended to depict the general structure of the application. It should also be appreciated that the drawings described below represent only some embodiments of the application, and that numerous other embodiments can be derived from these drawings without departing from the scope of the application.

[0023] In the drawings:

[0024] Figure 1 is a structural schematic diagram of the present application;

[0025] Figure 2 is a structural schematic diagram of the present application;

[0026] Figure 3 is a pre-bent perforated plate schematic diagram of the present application;

[0027] Figure 4 is a pre-bent perforated plate schematic diagram of the present application;

[0028] Figure 5 is a pre-bent perforated plate schematic diagram of the present application;

[0029] Figure 6 is a schematic diagram of an extended structure of the present application.

[0030] The present application will be further explained with reference to the drawings and the following examples. DETAILED DESCRIPTION

[0031] Embodiments of the present application will now be described in detail with reference to the drawings. Although the present application is illustrated and described in connection with specific embodiments, it will be appreciated that the application is not limited to these embodiments. Rather, the present application is intended to cover all alternatives, modifications and equivalents falling within the scope of the present application. It should be appreciated that those skilled in the art will be able to devise numerous alternative arrangements which, although not explicitly described herein, embody the principles of the application and are thus within its spirit and scope.

[0032] It should be noted that some terms are used in the description and claims to refer to particular components. One skilled in the art will understand that the same component can be referred to by different terms. This description and claims are not intended to be limited to the terms used. The description and claims are intended to cover all functional equivalents of the components. The description that follows is intended to illustrate preferred embodiments of the present application and is not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims.

[0033] In order to facilitate the understanding of the embodiments of the present application, the following will be further explained and described with several specific examples in conjunction with the accompanying drawings, and each drawing does not constitute a limitation on the embodiments of the present application.

[0034] In order to better understand, as shown in Figures 1 to 6 The negative Poisson's ratio tubular structure for buffering and energy absorption is a tubular structure with a bidirectional reentrant cross section, four inner concave linear connection structures are used to replace four inner concave sharp corners of the four-corner star-shaped structure to obtain a bidirectional reentrant cross section, and the pores in the tubular structure are periodically and uniformly distributed in the transverse and longitudinal directions, and the distance between adjacent pores is less than the wall thickness of the tubular structure, so that the pores collapse first during the axial compression of the tubular structure, and the tubular structure has a negative Poisson's ratio characteristic.

[0035] In the preferred embodiment of the negative Poisson's ratio tubular structure for buffering and energy absorption, the linear connection structure is disconnected and used as a rivet connection to decompose the tubular structure with a bidirectional reentrant cross section into four identical pre-bent perforated plates 1, and the negative Poisson's ratio tubular structure for buffering and energy absorption is assembled by four pre-bent perforated plates 1 and a plurality of rivets 2.

[0036] In the preferred embodiment of the negative Poisson's ratio tubular structure for buffering and energy absorption, the pre-bent perforated plate 1 includes a corner structure of a four-corner star-shaped structure, the corner structure has a first plate and a second plate bent at a predetermined angle with the first plate, the first plate is bent at an end to form a linear plate of a linear connection structure, and the second plate is bent at an end to form a linear plate of another linear connection structure.

[0037] In the preferred embodiment of the negative Poisson's ratio tubular structure for buffering and energy absorption, a connecting rib is arranged at the bent portion of the second plate and the first plate.

[0038] In the preferred embodiment of the negative Poisson's ratio tubular structure for energy absorption and buffering, the rivet connection of the linear plates is provided with a reserved hole for connecting the rivet, and the linear plates of the adjacent linear connection structure are riveted to form a negative Poisson's ratio tubular structure with a bidirectional reentrant cross-section based on the reserved hole after the combination of the pre-bent perforated plates 1.

[0039] In the preferred embodiment of the negative Poisson's ratio tubular structure for energy absorption and buffering, the pre-bent perforated plate 1 is a stainless steel flat plate.

[0040] In the preferred embodiment of the negative Poisson's ratio tubular structure for energy absorption and buffering, the long axis and the short axis of the adjacent pores are orthogonal.

[0041] In the preferred embodiment of the negative Poisson's ratio tubular structure for energy absorption and buffering, the pore shape includes an ellipse, a rhombus, or a hexagon.

[0042] In the preferred embodiment of the negative Poisson's ratio tubular structure for energy absorption and buffering, the negative Poisson's ratio tubular structure for energy absorption and buffering is a symmetric structure.

[0043] The manufacturing method of the negative Poisson's ratio tubular structure for energy absorption and buffering includes the following steps,

[0044] According to the overall size and cross-sectional size of the negative Poisson's ratio tubular structure for energy absorption and buffering, the size of the pre-bent perforated plate is obtained, and according to the overall size, Poisson's ratio, and response stress level of the negative Poisson's ratio tubular structure for energy absorption and buffering, the pore size on the pre-bent perforated plate and the distance between adjacent pores are obtained,

[0045] According to the size of the pre-bent perforated plate and the pore size on the pre-bent perforated plate and the distance between adjacent pores, the pre-perforated plate is cut on the flat plate by laser cutting or die pressing, and the pre-bent perforated plate is bent at a predetermined angle at a predetermined bending position to obtain four pre-bent perforated plates,

[0046] The pre-bent perforated plates are arranged in an interleaved manner, and the rivet holes are aligned for riveting to obtain a tubular structure with a bidirectional reentrant cross-section.

[0047] In one embodiment, the tubular structure with a cross section of a two-way reentrant configuration has periodic and uniform orthogonal distribution of holes in the transverse and longitudinal directions of the wall surface. The tubular structure with a cross section of a two-way reentrant configuration is decomposed into four identical parts, and the four identical parts can be assembled to form the designed negative Poisson's ratio tubular structure for energy absorption. The two-way reentrant configuration cross section is evolved from a four-point star structure, and the four concave corners of the four-point star structure are replaced by linear connection structures, and the two-way reentrant configuration is obtained. Then, the reentrant configuration is disconnected at the linear connection, and the linear connection is used as a rivet connection, and the two-way reentrant configuration is decomposed into four identical bending configurations. The negative Poisson's ratio tubular structure for energy absorption can be obtained by assembling four pre-bending perforated plates 1 and a plurality of rivets.

[0048] The pre-bending perforated plate 1 is obtained by perforating and bending a flat plate of a suitable size. The holes on the plate are periodically distributed, the long axis and the short axis of the adjacent holes are orthogonal, and a certain distance is reserved between the holes. The shape of the holes on the plate can be elliptical, rhombic, hexagonal, etc. The invention selects elliptical holes. At the same time, connecting ribs are added at the bending part to facilitate bending without affecting the stability of the structure during compression deformation. A circular hole is reserved at the center of the unit at the rivet connection of the plate. After the pre-bending perforated plate 1 is assembled, the parts are connected by rivets to form a complete negative Poisson's ratio tubular structure with a cross section of a two-way reentrant configuration for energy absorption. Rubber, resin and other materials are often used as the matrix material of negative Poisson's ratio metamaterials, but their carrying capacity, impact resistance and energy absorption capacity are weak. Metal-based negative Poisson's ratio metamaterials have higher carrying capacity and impact resistance, and therefore have greater application value. The substrate in the invention is a stainless steel flat plate.

[0049] The manufacturing method of the negative Poisson's ratio tubular structure for energy absorption includes the following steps:

[0050] (1) According to the overall size of the required tubular structure, the cross-sectional size of the structure is designed to obtain the size of the pre-bending perforated plate 1. According to the overall size of the plate and the required Poisson's ratio and response stress level, the size of the elliptical hole on the plate and the distance between adjacent holes are designed, and bending ribs are reserved at the bending part. At the same time, according to the overall size, the size of the rivet is selected, and the rivet holes are reserved at the center of each solid unit at the rivet connection part.

[0051] (2) According to the designed size, four identical flat plates are selected, and the material at the designed hole is removed on the flat plate by laser cutting or die pressing to obtain a pre-perforated plate. Then, the pre-perforated plate is bent at the predetermined bending part by die pressing to obtain a pre-bending perforated plate 1.

[0052] (3) The obtained pre-bent perforated plate 1 is combined in staggered arrangement, the rivet holes are matched, rivets with appropriate size and material are selected to rivet the combined tubular structure, and a negative Poisson's ratio tubular structure with bidirectional reentrant section for buffering and energy absorption is obtained. The deformation mode, mechanical response, Poisson's ratio and energy absorption performance of the structure can be obtained through axial compression test.

[0053] In one embodiment, the negative Poisson's ratio tubular structure for buffering and energy absorption includes a pre-bent perforated plate 1 and a rivet 2. The four inner concave corners of the four-star structure are replaced by linear connection structures, and the reentrant structure is obtained. The reentrant structure is disconnected at the linear connection, and the linear connection is used as the rivet connection, so that the bidirectional reentrant structure can be decomposed into four identical bent structures, as shown in Figure 2 The negative Poisson's ratio tubular structure for buffering and energy absorption can be obtained by assembling four pre-bent perforated plates and a plurality of rivets. According to the overall size of the tubular structure, including length L, width W, height H and plate thickness T, as shown in Figure 1 The cross-sectional size of the structure is designed, and the size of the pre-bent perforated plate, including length l and height h, is calculated. In this embodiment, the overall size of the tubular structure is selected as follows: length L is 63 mm, width W is 63 mm, height H is 95 mm, and plate thickness T is 2 mm; the size of the flat plate is selected as follows: length 1 is 82 mm, and height h is 95 mm.

[0054] As shown in Figure 3 The long axis of the elliptical hole on the plate is a, the short axis is b, and the distance between adjacent holes is c. It is worth noting that the distance c between the holes is less than the plate thickness T, so as to ensure that the structure first collapses during axial compression, rather than lateral buckling of the tube, thereby ensuring that the structure has a negative Poisson's ratio characteristic. A bending rib r is reserved at the bending position to facilitate bending processing without affecting the stability of the structure during compression deformation. At the same time, rivets with appropriate size are selected according to the overall size, and rivet holes with diameter d are reserved at the center of each solid unit. In this embodiment, the long axis a of the elliptical hole is 12 mm, the short axis b is 4 mm, and the distance between adjacent holes is 1.5 mm; the bending rib length r is 2 mm; and the rivet hole diameter d is 2.5 mm. According to the designed size, four identical flat plates are selected, and the material at the designed hole position on the flat plate is removed by laser cutting or molding to obtain a pre-perforated plate, as shown in Figure 3 Further, the pre-perforated plate is bent at the predetermined bending position by a designed angle a and β by molding to obtain a pre-bent perforated plate, as shown in Figure 4 and Figure 5 In this embodiment, the base plate is a 2 mm thick 316L stainless steel plate, and the bending angles a and β are designed to be 30° and 150°, respectively.

[0055] The obtained pre-bent perforated plate is combined in staggered arrangement, the rivet holes are aligned, rivets with appropriate size and material are selected to rivet the combined tubular structure, and a negative Poisson's ratio tubular structure with a bidirectional reentrant cross section for buffering and energy absorption is obtained, as shown in Figure 1 In this embodiment, the structural substrate is 316L stainless steel, so the rivet is made of 304 stainless steel with similar material properties, and the rivet specification is M2.4x6mm. The deformation mode, mechanical response, Poisson's ratio and energy absorption performance of the structure can be obtained by axial compression test. The structure can change the ratio of the hole length in the horizontal and vertical directions to design the effective compression strain range and the Poisson's ratio, and change the distance between adjacent holes, the size and number of holes, the thickness of the substrate, the cross-sectional size, and the overall size of the tubular structure to design the mechanical response and energy absorption capacity of the structure. According to the specific engineering application scene, a multi-objective optimization method can be used to design a negative Poisson's ratio tubular structure with strong energy absorption performance and low peak stress for buffering and energy absorption to complete the task of impact protection and buffering, and ensure the protection object is not damaged.

[0056] The above describes the basic principles of the present application in combination with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above disclosed specific details are only for the purpose of example and understanding, and are not limited to the above specific details. The above description does not limit the application to the above specific details.

[0057] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although the above has discussed a plurality of example aspects and embodiments, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations.

Claims

1. A negative Poisson's ratio tubular structure for energy absorption and cushioning, characterized by, It is a tubular structure with a cross section of a bidirectional reentrant configuration, replacing the four concave corners of the four-corner star-shaped structure with four concave linear connection structures to obtain a cross section of a bidirectional reentrant configuration, periodic uniform orthogonal distribution of pores in the transverse and longitudinal directions of the tubular structure, the distance between adjacent pores is less than the wall thickness of the tubular structure, so that the tubular structure first appears pore collapse during axial compression, so that the tubular structure has a negative Poisson's ratio characteristic, the linear connection structure is disconnected and serves as a rivet connection to decompose the tubular structure with a cross section of a bidirectional reentrant configuration into four identical pre-bent perforated plates, a negative Poisson's ratio tubular structure for energy absorption is obtained by assembling four pre-bent perforated plates and a number of rivets, wherein the obtained pre-bent perforated plates are staggered and combined, the rivet holes are aligned, and the rivets are riveted to obtain a negative Poisson's ratio tubular structure for energy absorption with a bidirectional reentrant cross section, the structure changes the pore length ratio of the transverse and longitudinal axes to design the compression strain range and Poisson's ratio size.

2. A negative Poisson's ratio tubular structure for cushioning and energy absorption as claimed in claim 1, wherein, The pre-bent perforated plate includes a corner structure of a four-corner star-shaped structure, the corner structure has a first plate and a second plate bent at a predetermined angle with the first plate, the first plate is linearly extended at a predetermined angle to form a linear plate of a linear connection structure, and the second plate is linearly extended at a predetermined angle to form a linear plate of another linear connection structure.

3. A negative Poisson's ratio tubular structure for cushioning and energy absorption as claimed in claim 1, wherein, The pre-bent perforated plate is a stainless steel flat plate.

4. A negative Poisson's ratio tubular structure for cushioning and energy absorption according to claim 1, wherein, The long axis and the short axis of the adjacent pores are orthogonal.

5. A negative Poisson's ratio tubular structure for cushioning and energy absorption according to claim 1, wherein, The pore shape includes an ellipse, a rhombus, or a hexagon.

6. A negative Poisson's ratio tubular structure for cushioning and energy absorption according to claim 1, wherein, The negative Poisson's ratio tubular structure for energy absorption is a symmetrical structure.

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