阅读说明：本技术 一种双箭头型负泊松比结构体 (Double-arrow type negative Poisson ratio structure body ) 是由 王剑锋 杨娜 李卫华 刘逸群 赵汗青 于 2019-08-06 设计创作，主要内容包括：一种双箭头型负泊松比结构体,涉及空间点阵结构的结构体领域,包括双箭头型负泊松比结构单元,双箭头型负泊松比结构单元包括上横梁、下横梁、第一上斜撑杆、第二上斜撑杆、第一下斜撑杆、第二下斜撑杆、第一中斜撑杆和第二中斜撑杆,第一上斜撑杆、第二上斜撑杆、第一下斜撑杆和第二下斜撑杆的下端分别设有第一上连接座、第二上连接座、第一下连接座和第二下连接座,形成双箭头型负泊松比结构单元；双箭头型负泊松比结构单元在空间上以第一上连接座、第二上连接座、第一下连接座、第二下连接座上横梁和下横梁为连接件组合连接为立体结构的双箭头型负泊松比结构体。具有结构简单、稳定性高,单位空间内质量小,抗压和抗冲击能力强等优点。(A double-arrow negative Poisson ratio structural body relates to the field of structural bodies of space lattice structures and comprises a double-arrow negative Poisson ratio structural unit, wherein the double-arrow negative Poisson ratio structural unit comprises an upper cross beam, a lower cross beam, a first upper inclined stay bar, a second upper inclined stay bar, a first lower inclined stay bar, a second lower inclined stay bar, a first middle inclined stay bar and a second middle inclined stay bar, and the lower ends of the first upper inclined stay bar, the second upper inclined stay bar, the first lower inclined stay bar and the second lower inclined stay bar are respectively provided with a first upper connecting seat, a second upper connecting seat, a first lower connecting seat and a second lower connecting seat to form a double-arrow negative Poisson ratio structural unit; the double-arrow-shaped negative Poisson ratio structure unit is a double-arrow-shaped negative Poisson ratio structure body which is in a three-dimensional structure and is formed by combining and connecting a first upper connecting seat, a second upper connecting seat, a first lower connecting seat, a second lower connecting seat upper cross beam and a lower cross beam in space by using a connecting piece. The device has the advantages of simple structure, high stability, small mass in unit space, strong compression resistance and impact resistance and the like.)

1. A double-arrow type negative Poisson ratio structure body is characterized by comprising a double-arrow type negative Poisson ratio structure unit, wherein the double-arrow type negative Poisson ratio structure unit comprises an upper cross beam and a lower cross beam, a first upper inclined stay bar and a second upper inclined stay bar which incline downwards are respectively arranged at two ends of the upper cross beam, the first upper inclined stay bar and the second upper inclined stay bar form an upper arrow, a first lower inclined stay bar and a second lower inclined stay bar which incline downwards are respectively arranged at two ends of the lower cross beam, the first lower inclined stay bar and the second lower inclined stay bar form a lower arrow, a first middle inclined stay bar and a second middle inclined stay bar are respectively arranged between two ends of the upper cross beam and the lower ends of the first lower inclined stay bar and the second lower inclined stay bar, a first upper connecting seat, a second upper connecting seat, a first lower connecting seat and a second lower connecting seat are respectively arranged at the lower ends of the first upper inclined stay bar, the second upper inclined stay bar, forming a double-arrow type negative Poisson ratio structural unit;

The two double-arrow-head type negative Poisson ratio structural units are connected in a first direction to form a first structural component in a mode that a first upper connecting seat and a second upper connecting seat of the two adjacent double-arrow-head type negative Poisson ratio structural units are fixedly connected, and a first lower connecting seat and a second lower connecting seat of the two adjacent double-arrow-head type negative Poisson ratio structural units are fixedly connected;

The two first structural components are arranged in parallel with each other along a second direction, a double-arrow type negative Poisson ratio structural unit arranged in a third direction is arranged between two adjacent double-arrow type negative Poisson ratio structural units in the second direction (of two adjacent first structural components), and the middle part of the upper side of an upper beam and the middle part of the lower side of the double-arrow type negative Poisson ratio structural unit arranged in the third direction are respectively and fixedly connected with the middle part of the upper side of a lower beam and the middle part of the lower side of the lower beam of the two adjacent double-arrow type negative Poisson ratio structural units in the second direction to form a second structural component;

At least two second structure components are connected in a mode of fixedly connecting the first upper connecting seat and the second upper connecting seat and fixedly connecting the first lower connecting seat and the second lower connecting seat of two adjacent double-arrow-shaped negative Poisson ratio structure units arranged in the third direction to form a double-arrow-shaped negative Poisson ratio structure body.

2. The double-arrow negative poisson's ratio structural body of claim 1, wherein in the second structural assembly, a double-arrow negative poisson's ratio structural unit arranged in a third direction is arranged above or below the uppermost or lowermost double-arrow negative poisson's ratio structural unit in the second direction, and the middle of the lower side of the lower beam or the middle of the upper side of the upper beam of the double-arrow negative poisson's ratio structural unit arranged in the third direction is fixedly connected with the middle of the upper side of the upper beam or the middle of the lower side of the lower beam of the double-arrow negative poisson's ratio structural unit in the second direction.

3. The double-arrow-shaped negative Poisson ratio structure body of claim 1, wherein a third-direction reinforcing double-arrow-shaped negative Poisson ratio structure unit is arranged above the fixed connection position of the first upper connection seat and the second upper connection seat of two adjacent double-arrow-shaped negative Poisson ratio structure units arranged in the first direction in the double-arrow-shaped negative Poisson ratio structure body, and the middle part of the lower side of the lower beam of the third-direction reinforcing double-arrow-shaped negative Poisson ratio structure unit is fixedly connected with the fixed connection position of the first upper connection seat and the second upper connection seat; when the double-arrow type negative Poisson ratio structural unit arranged in the first direction is arranged above the reinforcing third-direction double-arrow type negative Poisson ratio structural unit, the middle part of the upper side of the upper beam of the reinforcing third-direction double-arrow type negative Poisson ratio structural unit is fixedly connected with the fixed connection part of the first lower connecting seat and the second lower connecting seat of the two adjacent double-arrow type negative Poisson ratio structural units arranged in the first direction above the upper beam; a first-direction double-arrow-head negative poisson ratio structure unit for reinforcing is arranged in a first direction above the fixed connection position of a first upper connection seat and a second upper connection seat of two adjacent double-arrow-head negative poisson ratio structure units arranged in a third direction in the double-arrow-head negative poisson ratio structure body, and the middle part of the lower side of a lower beam of the first-direction double-arrow-head negative poisson ratio structure unit for reinforcing is fixedly connected with the fixed connection position of the first upper connection seat and the second upper connection seat; when the double-arrow type negative Poisson ratio structural unit arranged in the third direction is arranged above the first-direction double-arrow type negative Poisson ratio structural unit for reinforcement, the first lower connecting seat and the second lower connecting seat of the upper beam middle part of the first-direction double-arrow type negative Poisson ratio structural unit for reinforcement and the adjacent two double-arrow type negative Poisson ratio structural units arranged in the third direction above the upper beam middle part are fixedly connected.

4. The double-arrow negative Poisson ratio structure of claim 1, wherein the middle part of the upper side of the upper beam and the middle part of the lower side of the lower beam of the double-arrow negative Poisson ratio structure unit are respectively provided with an upper clamping groove and a lower clamping groove which can enable the upper beam and the lower beam to be mutually crossed, inserted and embedded; the first upper connecting seat and the second upper connecting seat are fixedly connected and then are in an inverted lower cross beam shape, and the first lower connecting seat and the second lower connecting seat are fixedly connected and then are in an inverted upper cross beam shape; the upper sides of the outer ends of the first upper connecting seat and the second upper connecting seat of the double-arrow-head type negative Poisson ratio structural unit are provided with connecting notches, and the lower sides of the outer ends of the first lower connecting seat and the second lower connecting seat are provided with connecting notches.

Technical Field

the invention relates to the field of structures of space lattice structures, in particular to a design and assembly process of a space lattice structure, and specifically relates to a double-arrow negative Poisson's ratio structure which is simple in structure, high in stability, small in mass (density) in unit space and strong in compression resistance and impact resistance.

Background

The lattice structure is known to be a novel lightweight structure, and compared with the traditional foam and honeycomb structures, the lattice structure has higher specific strength and specific rigidity, and the core has larger porosity inside, so that the lattice structure has wider prospects in the aspect of multifunctional structure application. The negative Poisson ratio structure has excellent mechanical property and good energy absorption capacity, has wide application prospect in the industrial design of automobiles, and can be applied to the structural design to improve the performance of parts and carry out lightweight design.

The space lattice structure is a novel laminated plate structure and is also a light-weight vehicle body structure. The mechanical characteristics of the space lattice structure are researched, and a model is established according to related experimental data, so that the method has important significance for automobile lightweight.

The negative poisson ratio structure has unique mechanical properties such as better energy absorption characteristic under external force impact due to the characteristic that the negative poisson ratio structure transversely shrinks when being compressed in the axial direction. The national intellectual property office 2014, 2, 12, publishes a negative poisson ratio structural component with the name of: 201310566039.5 which discloses an impact or cushioning member using a negative poisson's ratio structure, but the impact or cushioning member of this structure has the disadvantages of poor structural stability, pressure resistance and impact resistance; the double-arrow negative Poisson ratio structure has the defects of complex manufacturing method and higher cost, and limits the practical use and experimental research of the structure.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provide a double-arrow negative Poisson ratio structure which has excellent impact energy absorption characteristic, strong pressure resistance and impact resistance, simple manufacturing method, low cost and light weight of a real lattice structure.

The invention solves the defects of the prior art and adopts the technical scheme that:

A double-arrow type negative Poisson ratio structure body is characterized by comprising a double-arrow type negative Poisson ratio structure unit, wherein the double-arrow type negative Poisson ratio structure unit comprises an upper cross beam and a lower cross beam, a first upper inclined stay bar and a second upper inclined stay bar which incline downwards are respectively arranged at two ends of the upper cross beam, the first upper inclined stay bar and the second upper inclined stay bar form an upper arrow, a first lower inclined stay bar and a second lower inclined stay bar which incline downwards are respectively arranged at two ends of the lower cross beam, the first lower inclined stay bar and the second lower inclined stay bar form a lower arrow, a first middle inclined stay bar and a second middle inclined stay bar are respectively arranged between two ends of the upper cross beam and the lower ends of the first lower inclined stay bar and the second lower inclined stay bar, a first upper connecting seat, a second upper connecting seat, a first lower connecting seat and a second lower connecting seat are respectively arranged at the lower ends of the first upper inclined stay bar, the second upper inclined stay bar, forming a double-arrow type negative Poisson ratio structural unit;

The two double-arrow-head type negative Poisson ratio structural units are connected in a first direction to form a first structural component in a mode that a first upper connecting seat and a second upper connecting seat of the two adjacent double-arrow-head type negative Poisson ratio structural units are fixedly connected, and a first lower connecting seat and a second lower connecting seat of the two adjacent double-arrow-head type negative Poisson ratio structural units are fixedly connected;

The two first structural components are arranged in parallel with each other along a second direction, a double-arrow type negative Poisson ratio structural unit arranged in a third direction is arranged between two adjacent double-arrow type negative Poisson ratio structural units in the second direction (of two adjacent first structural components), and the middle part of the upper side of an upper beam and the middle part of the lower side of the double-arrow type negative Poisson ratio structural unit arranged in the third direction are respectively and fixedly connected with the middle part of the upper side of a lower beam and the middle part of the lower side of the lower beam of the two adjacent double-arrow type negative Poisson ratio structural units in the second direction to form a second structural component;

At least two second structure components are connected in a mode of fixedly connecting the first upper connecting seat and the second upper connecting seat and fixedly connecting the first lower connecting seat and the second lower connecting seat of two adjacent double-arrow-shaped negative Poisson ratio structure units arranged in the third direction to form a double-arrow-shaped negative Poisson ratio structure body.

In the second structural assembly, a double-arrow type negative poisson ratio structural unit arranged in a third direction is arranged above or below the uppermost or lowermost double-arrow type negative poisson ratio structural unit in the second direction, and the middle part of the lower side of a lower cross beam or the middle part of the upper side of an upper cross beam of the double-arrow type negative poisson ratio structural unit arranged in the third direction is fixedly connected with the middle part of the upper side of an upper cross beam or the middle part of the lower side of a lower cross beam of the double-arrow type negative poisson ratio structural unit in the adjacent second direction.

a third-direction reinforcing double-arrow-head negative poisson ratio structural unit is arranged in a third direction above the fixed connection position of a first upper connecting seat and a second upper connecting seat of two adjacent double-arrow-head negative poisson ratio structural units arranged in the double-arrow-head negative poisson ratio structural body in the first direction, and the middle part of the lower side of a lower cross beam of the third-direction reinforcing double-arrow-head negative poisson ratio structural unit is fixedly connected with the fixed connection position of the first upper connecting seat and the second upper connecting seat; when the double-arrow type negative Poisson ratio structural unit arranged in the first direction is arranged above the reinforcing third-direction double-arrow type negative Poisson ratio structural unit, the middle part of the upper side of the upper beam of the reinforcing third-direction double-arrow type negative Poisson ratio structural unit is fixedly connected with the fixed connection part of the first lower connecting seat and the second lower connecting seat of the two adjacent double-arrow type negative Poisson ratio structural units arranged in the first direction above the upper beam; a first-direction double-arrow-head negative poisson ratio structure unit for reinforcing is arranged in a first direction above the fixed connection position of a first upper connection seat and a second upper connection seat of two adjacent double-arrow-head negative poisson ratio structure units arranged in a third direction in the double-arrow-head negative poisson ratio structure body, and the middle part of the lower side of a lower beam of the first-direction double-arrow-head negative poisson ratio structure unit for reinforcing is fixedly connected with the fixed connection position of the first upper connection seat and the second upper connection seat; when the double-arrow type negative Poisson ratio structural unit arranged in the third direction is arranged above the first-direction double-arrow type negative Poisson ratio structural unit for reinforcement, the first lower connecting seat and the second lower connecting seat of the upper beam middle part of the first-direction double-arrow type negative Poisson ratio structural unit for reinforcement and the adjacent two double-arrow type negative Poisson ratio structural units arranged in the third direction above the upper beam middle part are fixedly connected. The first upper connecting seat and the second upper connecting seat and the first lower connecting seat of the two adjacent reinforcing first-direction double-arrow-head negative Poisson ratio structural units are fixedly connected; the first upper connecting seat and the second upper connecting seat and the first lower connecting seat and the second lower connecting seat of the two adjacent reinforcing third-direction double-arrow-head negative poisson ratio structural units are fixedly connected; the joint of two adjacent reinforcing first-direction double-arrow-head negative Poisson ratio structural units is fixedly connected with the joint of two adjacent reinforcing third-direction double-arrow-head negative Poisson ratio structural units crossed with the joint. . After the first-direction double-arrow-head negative Poisson ratio structural unit for reinforcement and the third-direction double-arrow-head negative Poisson ratio structural unit for reinforcement are additionally arranged, the number of cell elements is increased under the condition that the double-arrow-head negative Poisson ratio structural body has the same volume and the same mass as the original double-arrow-head negative Poisson ratio structural body, the stability of the structure is improved, the deformation is greatly reduced, the structure is more stable, and the shock resistance is better; the strength and the rigidity are improved, and the safety and the stability are better.

The middle part of the upper side of an upper beam and the middle part of the lower side of a lower beam of the double-arrow negative Poisson ratio structural unit are respectively provided with an upper clamping groove and a lower clamping groove which can enable the upper beam and the lower beam to be mutually crossed, spliced and embedded; the first upper connecting seat and the second upper connecting seat are fixedly connected and then are in an inverted lower cross beam shape, and the first lower connecting seat and the second lower connecting seat are fixedly connected and then are in an inverted upper cross beam shape; the upper sides of the outer ends of the first upper connecting seat and the second upper connecting seat of the double-arrow-head type negative Poisson ratio structural unit are provided with connecting notches, and the lower sides of the outer ends of the first lower connecting seat and the second lower connecting seat are provided with connecting notches. The assembly and the connection are more convenient and stable, the manufacture is simple and convenient, and the cost is reduced.

In the double-arrow type negative Poisson's ratio structural unit, the height of the upper beam is the same as that of the lower beam; the first upper diagonal brace and the second upper diagonal brace are respectively parallel to the first lower diagonal brace and the second lower diagonal brace; the length of the upper beam is N, the vertical distance between the upper end surface of the upper beam and the lower end surface of the first lower connecting seat is H, the height of the double-arrow type negative Poisson's ratio structural unit is H, the included angle between the first middle inclined stay bar and the vertical direction is, and the included angle between the first lower inclined stay bar and the vertical direction is; the distance between first connecting seat and second connecting seat (left and right) both ends face is width (span) L of double arrow type negative poisson's ratio constitutional unit down, wherein, N: l =1:6-10, 30-60 degrees, 40-70 degrees; preferably 40 degrees to 50 degrees, preferably 55 degrees to 65 degrees.

According to the invention, the structure of the double-arrow type negative Poisson ratio structural unit is changed, so that the double-arrow type negative Poisson ratio structural body is changed into an assembled type, the design of the lattice structure has flexibility and operability, the structure is convenient to disassemble and assemble, and meanwhile, the whole design process is simplified. The double-arrow negative Poisson ratio structural body has the variable rigidity characteristic, the rigidity of the structure becomes larger and larger along with the action of external force, and the deformation resistance is stronger and stronger; the structure of the double-arrow type negative Poisson ratio structural unit reduces gaps on the premise of ensuring the performance, reduces the relative density of a lattice structure, lightens the weight and realizes light weight. The invention has the advantages of excellent impact energy absorption characteristic, strong pressure resistance and impact resistance, simple manufacturing method, low cost, realization of light lattice structure and the like.

Drawings

FIG. 1 is a schematic structural diagram of a double-arrow type negative Poisson's ratio structural unit in the present invention.

Fig. 2 is a schematic perspective view of a double-arrow type negative poisson's ratio structural unit according to the present invention.

fig. 3 is a schematic perspective view of a double-arrow negative poisson's ratio structure according to the present invention.

fig. 4 is a schematic top view of a double-arrow type negative poisson's ratio structure according to the present invention.

Fig. 5 is a schematic perspective view of the double-arrow-head negative poisson ratio structure of the present invention after a third-direction double-arrow-head negative poisson ratio structural unit for reinforcement and a first-direction double-arrow-head negative poisson ratio structural unit for reinforcement are added.

Fig. 6 is a schematic top view of the double-arrow type negative poisson's ratio structure of the present invention with the reinforcing third-direction double-arrow type negative poisson's ratio structural unit and the reinforcing first-direction double-arrow type negative poisson's ratio structural unit added.

FIG. 7 is a schematic view of the construction of a laminate of the present invention after connecting the upper and lower connecting plates.

Detailed Description

The double-arrow type negative poisson ratio structural body shown in fig. 3 and 4 comprises a double-arrow type negative poisson ratio structural unit shown in fig. 1 and 2, the double-arrow type negative poisson ratio structural unit comprises an upper beam 8 and a lower beam 9 which are arranged in parallel, a first upper inclined strut 4 and a second upper inclined strut 10 which incline downwards (left and right) are respectively arranged at the left end and the right end of the upper beam 8, the first upper inclined strut 4 and the second upper inclined strut 10 form an upper arrow with the upper end being the upper beam, a first lower inclined strut 6 and a second lower inclined strut 12 which incline downwards (left and right) are respectively arranged at the left end and the right end of the lower beam 9, the first lower inclined strut 6 and the second lower inclined strut 12 form a lower arrow with the upper end being the lower beam, the two ends of the upper beam 8 are respectively fixedly connected with the lower ends of the first lower inclined strut 6 and the second lower inclined strut 12 through a first middle inclined strut 5 and a second inclined strut 11, the lower ends of the first upper inclined stay 4, the second upper inclined stay 10, the first lower inclined stay 6 and the second lower inclined stay 12 are respectively provided with a first upper connecting seat 2, a second upper connecting seat 13, a first lower connecting seat 3 and a second lower connecting seat 14 which are horizontal, so that a double-arrow type negative poisson's ratio structural unit is formed.

As shown in fig. 3 and 4, the simplest double-arrow negative poisson ratio structure constructed by using 16 double-arrow negative poisson ratio structural units has a specific structure that: the two double-arrow-head type negative poisson ratio structural units are connected in a first direction (X direction and left-right direction) to form a first structural component in a mode that a first upper connecting seat and a second upper connecting seat of the two adjacent double-arrow-head type negative poisson ratio structural units are fixedly connected, and a first lower connecting seat and a second lower connecting seat of the two adjacent double-arrow-head type negative poisson ratio structural units are fixedly connected; the two first structural components are arranged in parallel with each other along a second direction (Y direction, up-down direction), a double-arrow type negative Poisson ratio structural unit arranged in a third direction (Z direction, front-back direction) is arranged between two adjacent double-arrow type negative Poisson ratio structural units of two adjacent first structural components in the second direction, the middle part of the upper side of an upper beam and the middle part of the lower side of the double-arrow type negative Poisson ratio structural unit arranged in the third direction (Z direction) are respectively and fixedly connected with the middle part of the upper side of a lower beam and the middle part of the lower side of the lower beam of two adjacent double-arrow type negative Poisson ratio structural units in the second direction (two adjacent first structural components), a double-arrow type negative Poisson ratio structural unit arranged in the third direction (Z direction) is arranged above the double-arrow type negative Poisson ratio structural unit (of the first structural components) at the top in the second direction (Y direction), the middle part of the lower side of the lower cross beam of the double-arrow type negative Poisson ratio structural unit arranged in the third direction (Z direction) is fixedly connected with the middle part of the upper side of the upper cross beam of the double-arrow type negative Poisson ratio structural unit in the adjacent second direction; forming a second structural component. The two second structural components are arranged in parallel in the third direction (Z direction), and the first upper connecting seat and the second upper connecting seat and the first lower connecting seat and the second lower connecting seat of the two adjacent double-arrow-shaped negative Poisson ratio structural units arranged in the third direction (Z direction) are fixedly connected to form a double-arrow-shaped negative Poisson ratio structural body with the minimum unit. The double-arrow type negative Poisson ratio structural units are additionally arranged on the periphery and the upper part and the lower part of the double-arrow type negative Poisson ratio structural body with the minimum unit in the above connection mode, and the double-arrow type negative Poisson ratio structural bodies with different target specifications can be obtained.

The invention is further improved, a third-direction double-arrow-head negative poisson ratio structure unit for reinforcing is arranged in a third direction (the double-arrow-head negative poisson ratio structure unit is inverted up and down) above the fixed connection position of a first upper connection seat and a second upper connection seat of two adjacent double-arrow-head negative poisson ratio structure units arranged in the first direction in the double-arrow-head negative poisson ratio structure body shown in the figures 3 and 4, and the middle part of the lower side (or the upper side) of a lower cross beam of the third-direction double-arrow-head negative poisson ratio structure unit for reinforcing is fixedly connected with the fixed connection position of the first upper connection seat and the second upper connection seat of the two adjacent double-arrow-head negative poisson ratio structure units arranged in the first direction; when a double-arrow-head type negative poisson ratio structure unit (fixedly connected with two first upper connecting seats and a second upper connecting seat) arranged in the first direction is arranged above the reinforcing third-direction double-arrow-head type negative poisson ratio structure unit, fixedly connecting the first lower connecting seats and the second lower connecting seats of the two adjacent double-arrow-head type negative poisson ratio structure units arranged in the first direction above the middle part of the upper cross beam (or the lower side of the lower cross beam) of the reinforcing third-direction double-arrow-head type negative poisson ratio structure unit; a first direction double-arrow-head type negative poisson ratio structure unit for reinforcing is arranged above a fixed connection position of a first upper connection seat and a second upper connection seat of two adjacent double-arrow-head type negative poisson ratio structure units arranged in a third direction in the double-arrow-head type negative poisson ratio structure body, wherein the first direction double-arrow-head type negative poisson ratio structure unit for reinforcing is arranged in the first direction (the double-arrow-head type negative poisson ratio structure unit is inverted up and down), and the fixed connection position of the first upper connection seat and the second upper connection seat of the lower beam (or the upper side of the upper beam) of the first direction double-arrow-head type negative poisson ratio structure unit for reinforcing is fixedly connected with the fixed connection position of the first upper connection seat and the second upper connection seat of the two adjacent double-arrow-head; when the double-arrow-head type negative poisson ratio structure unit (fixedly connected with the two first upper connecting seats and the second upper connecting seat) arranged in the third direction is arranged above the first-direction double-arrow-head type negative poisson ratio structure unit for reinforcement, the first lower connecting seats and the second lower connecting seats of the two adjacent double-arrow-head type negative poisson ratio structure units are fixedly connected at the fixed connection position of the middle part of the upper cross beam upper side (lower cross beam lower side) of the first-direction double-arrow-head type negative poisson ratio structure unit and the third direction arranged above the upper cross beam upper side (lower cross beam lower side). The first upper connecting seat and the second upper connecting seat and the first lower connecting seat of the two adjacent reinforcing first-direction double-arrow-head negative Poisson ratio structural units are fixedly connected; the first upper connecting seat and the second upper connecting seat and the first lower connecting seat and the second lower connecting seat of the two adjacent reinforcing third-direction double-arrow-head negative poisson ratio structural units are fixedly connected; the joint of two adjacent reinforcing first-direction double-arrow-head negative Poisson ratio structural units is fixedly connected with the joint of two adjacent reinforcing third-direction double-arrow-head negative Poisson ratio structural units crossed with the joint. As can be seen from fig. 1 to 6, the upper middle part of the upper beam and the lower middle part of the lower beam of the double-arrow type negative poisson ratio structural unit are respectively provided with an upper clamping groove 7 and a lower clamping groove 16 which can be used for mutually (cross) cross inserting, embedding and clamping the upper beam (of one double-arrow type negative poisson ratio structural unit) and the lower beam (of the other double-arrow type negative poisson ratio structural unit); the first upper connecting seat and the second upper connecting seat (of two adjacent double-arrow-head type negative Poisson ratio structural units) are fixedly connected and then are in an inverted lower beam shape, and the first lower connecting seat and the second lower connecting seat are fixedly connected and then are in an inverted upper beam shape; the upper sides of the outer ends of a first upper connecting seat and a second upper connecting seat of the double-arrow-head type negative poisson ratio structural unit are provided with an upper connecting gap 1, and the lower sides of the outer ends of a first lower connecting seat and a second lower connecting seat are provided with a lower connecting gap 15, and the upper connecting gaps of the first upper connecting seat and the second upper connecting seat (of two adjacent double-arrow-head type negative poisson ratio structural units) are combined into a clamping groove which can be mutually (cross) crossly inserted, embedded and clamped with an upper clamping groove 7, a lower clamping groove 16 and two clamping grooves; the first lower connecting seat (of two adjacent double-arrow-head negative Poisson ratio structural units) and the second lower connecting seat are fixedly connected, and then the lower connecting gaps are combined into a clamping groove which can be mutually (cross) crossly inserted, embedded and clamped with the upper clamping groove 7, the lower clamping groove 16 and the two clamping grooves. The double-arrow negative poisson ratio structural body shown in fig. 5 and 6 is the double-arrow negative poisson ratio structural body after the third-direction double-arrow negative poisson ratio structural unit for reinforcement and the first-direction double-arrow negative poisson ratio structural unit for reinforcement are added in the double-arrow negative poisson ratio structural body shown in fig. 3 and 4; the third-direction double-arrow-head type negative Poisson ratio structure unit for reinforcement and the first-direction double-arrow-head type negative Poisson ratio structure unit for reinforcement are both double-arrow-head type negative Poisson ratio structure units which are arranged in an up-down inverted mode, an upper clamping groove 7 of each double-arrow-head type negative Poisson ratio structure unit arranged in an up-down inverted mode is in clamping fit with clamping grooves formed by two opposite upper connecting gaps below the upper clamping groove, and a lower clamping groove 16 of each double-arrow-head type negative Poisson ratio structure unit is in clamping fit or suspended with clamping grooves formed by two opposite lower connecting gaps above the lower clamping groove. Go up joint groove, lower joint groove, go up the setting of connection breach and connection breach down, not only make the equipment connection more convenient, firm, make simple and convenient, reduce cost, and under the prerequisite of retention ability, reduced the whole height of double arrow point type negative poisson ratio structure, go up joint groove, lower joint groove and last connection breach and the junction structural strength of the joint groove of connecting the breach constitution down unchangeably. The fixed connection in the invention is bonding, welding or clamping through a convex-concave structure.

In the double-arrow negative poisson ratio structure unit (a structure with symmetrical vertical centerlines of the upper cross beam and the lower cross beam), the heights (in the up-down direction) of the upper cross beam and the lower cross beam are the same (the shape and the size of the first upper connecting seat and the second upper connecting seat after being fixedly connected are the same as those of the inverted lower cross beam, and the shape and the size of the first lower connecting seat and the second lower connecting seat after being fixedly connected are the same as those of the inverted upper cross beam); the first upper diagonal brace and the second upper diagonal brace are respectively parallel to the first lower diagonal brace and the second lower diagonal brace; the length of the upper beam is N, the vertical distance between the upper end surface of the upper beam and the lower end surface of the first lower connecting seat (or the second lower connecting seat) is H, the height of the double-arrow type negative Poisson ratio structural unit is H, the included angle between the first middle diagonal brace (and the second middle diagonal brace) and the vertical direction (up and down) is, and the included angle between the first lower diagonal brace (and the second lower diagonal brace) and the vertical direction (up and down) is; the distance between first connecting seat and second connecting seat (left and right) both ends face is width (span) L of double arrow type negative poisson's ratio constitutional unit down, wherein, N: l =1:6-10, 30-60 degrees, 40-70 degrees; preferably 40 degrees to 50 degrees, preferably 55 degrees to 65 degrees.

The simulation experiment was performed by selecting the double-arrow type negative poisson ratio structure shown in fig. 3 and 4 and the double-arrow type negative poisson ratio structure shown in fig. 5 and 6, and the experimental data of the double-arrow type negative poisson ratio structure shown in fig. 3 and 4 before embedding and the experimental data of the double-arrow type negative poisson ratio structure shown in fig. 5 and 6 after embedding, and the specific experiment was as follows:

(1) the panels are provided on both upper and lower sides of the double-arrow type negative poisson's ratio structural body, and as shown in fig. 7, the panels added to both are the same.

(2) In the following simulation, the panel material was structural steel and the double-arrow negative poisson's ratio structural material was 6061 aluminum alloy.

(3) The two double-arrow negative poisson ratio structures have the same mass. The double-arrow type negative poisson's ratio structural body shown in fig. 5 and 6 has a larger number of double-arrow type negative poisson's ratio structural units, but has a smaller thickness, so that the two types of double-arrow type negative poisson's ratio structural bodies have the same mass.

(4) And (3) increasing the pressure with the same value to one side panel of the two double-arrow type negative Poisson ratio structures, and adding fixed constraint to the other side of the two double-arrow type negative Poisson ratio structures for simulation.

TABLE 1 stress analysis and comparison table for two double-arrow type negative Poisson ratio structural bodies

in the double-arrow type negative poisson's ratio structure shown in fig. 5 and 6, when the volume and the mass are the same as those of the double-arrow type negative poisson's ratio structure shown in fig. 3 and 4, that is, when the relative density is the same, the number of double-arrow type negative poisson's ratio structural units is increased, so that the connection area between the double-arrow type negative poisson's ratio structure and the panel is increased, and the structural stability is improved. As shown in table 1, the double-arrow type negative poisson's ratio structure shown in fig. 5 and 6 has a structural deformation 13% less than that of the double-arrow type negative poisson's ratio structure shown in fig. 3 and 4, and the maximum deformation is at the edge of the panel when the same force is applied, and the deformation is caused because the edge of the panel is not supported, and the double-arrow type negative poisson's ratio structure has a smaller internal deformation and absorbs energy more strongly; the maximum deformation of the double-arrow type negative poisson's ratio structural body shown in fig. 3 and 4 occurs not only at the panel edge but also inside the double-arrow type negative poisson's ratio structural body. Therefore, the double-arrow type negative poisson's ratio structure shown in fig. 5 and 6 is more stable in structure and better in impact resistance. The equivalent elastic strain and the equivalent stress are both calculated values according to a fourth intensity theory, namely Von-Mises stress strain. When the allowable stress strain of a given material is smaller, the smaller the equivalent elastic strain and the equivalent stress are, the safer the structure is, and the higher the strength is, the stronger the bearing capacity is. The equivalent elastic strain of the double-arrow type negative poisson's ratio structure shown in fig. 5 and 6 is about 47.8% and the equivalent stress is about 68.5% of the double-arrow type negative poisson's ratio structure shown in fig. 3 and 4; the double-arrow negative poisson ratio structure shown in fig. 5 and 6 improves the strength and rigidity of the whole structure, so that the structure is safer and more stable under the condition of bearing the same load.

Compared with the prior art, the invention mainly has the following advantages:

1. compare whole lattice structure, through the structure that changes the negative poisson ratio constitutional unit of double arrow point type, the negative poisson ratio constitutional unit of double arrow point type becomes assembled, makes lattice structure's design have flexibility and maneuverability, and structure easy dismounting simplifies overall design's process simultaneously.

2. Based on a discretization method, mechanical properties of the lattice structure are researched by designing a double-arrow type negative Poisson ratio structural unit, and on the basis of obtaining the strain stress of the double-arrow type negative Poisson ratio structural unit, the stress strain is converted into a whole according to a macroscopic structure, so that the mechanical properties of the lattice structure are obtained.

3. compared with the existing 3D printing technology which takes composite materials as base materials for lattice structures, the embedding and locking assembly technology has lower cost, and the strength of the double-arrow type negative Poisson ratio structural unit prepared by adopting metal materials is higher.

4. during the joining process, the grooves are joined. The integrity and the continuity of the lattice structure are protected, and the lattice structure is more favorable for resisting deformation.

5. The negative Poisson ratio structure has the variable rigidity characteristic, the rigidity of the structure is increased along with the action of external force, and the deformation resistance is also increased.

6. The specific structure of the double-arrow negative Poisson ratio structural unit reduces gaps on the premise of ensuring the performance, reduces the relative density of a lattice structure, lightens the weight and realizes light weight.