CN-116705202-B - Three-dimensional double-arrow negative poisson ratio structure and design method thereof

CN116705202BCN 116705202 BCN116705202 BCN 116705202BCN-116705202-B

Abstract

The invention provides a three-dimensional double-arrow negative poisson ratio structure, and relates to the technical field of negative poisson ratio metamaterials. The structure is formed by connecting a plurality of press-twisting units in an array mode, each press-twisting unit is formed by twisting and connecting a plurality of three-dimensional double-arrow single cells, and each three-dimensional double-arrow single cell is formed by vertically connecting two single-arrow frame bodies. The design method comprises the steps of drawing a two-dimensional sketch of a single-arrow frame on a front-view reference surface, drawing a two-dimensional sketch of the single-arrow frame by a two-way stretching distance t/2, cutting a square with the side length and the thickness of t at the joint of an inclined rod and a bottom rod to be used as a connection section of a lattice structure to obtain the single-arrow frame, rotating the single-arrow frame around an axis by an angle delta circumferential array to obtain a three-dimensional double-arrow unit cell, connecting a plurality of three-dimensional double-arrow unit cells and forming an upward linear array, and building a three-dimensional double-arrow negative poisson ratio structure in a plane. The invention has better mechanical property and energy absorption effect.

Inventors

LI FANGYI
WANG ZIJIE
ZHU DACHANG
ZHANG QIANG
WANG TAO
CHEN YUANWEN
ZENG RONG

Assignees

广州大学

Dates

Publication Date: 20260512
Application Date: 20230529

Claims (8)

1. The three-dimensional double-arrow negative poisson ratio structure is characterized in that a plurality of press-twisting units are connected in a linear array in a three-dimensional space, each press-twisting unit is formed by connecting a plurality of three-dimensional double-arrow single cells in a torsion sequence, each three-dimensional double-arrow single cell is formed by vertically connecting two single-arrow frame bodies, the crossed vertexes of the inclined rods of the two single-arrow frame bodies are integrally connected to form a top surface, the middle parts of the bottom rods of the two single-arrow frame bodies are vertically connected to form a bottom surface, the outer sides of the crossed parts of the inclined rods and the bottom rods form a connecting tangent plane, the connecting tangent plane is a rectangular plane, the connecting tangent plane is perpendicular to the top surface, the top surface of each three-dimensional double-arrow single cell is fixedly connected with the connecting tangent plane of the adjacent three-dimensional double-arrow single cell in sequence, the top surface and the bottom surface are cross planes, and the top surface and the bottom surface are parallel.
2. The three-dimensional double-arrow negative poisson's ratio structure according to claim 1, wherein the length and width of the cross-plane are equal.
3. The three-dimensional double-arrow negative poisson's ratio structure according to claim 1, wherein the rectangular plane is square.
4. The three-dimensional double-arrow negative poisson's ratio structure according to claim 1, wherein the top surface is seamlessly glued or integrally connected with the connection section.
5. The three-dimensional double-arrow negative poisson ratio structure according to claim 2, wherein the bottom surface is positioned on one side of the connecting lines of the end parts of the two diagonal rods, which is close to the top surface, and two ends of the bottom surface are respectively and fixedly connected with the bottom ends of the diagonal rods through the bottom rods.
6. A method of designing a three-dimensional double-arrow negative poisson's ratio structure according to any one of claims 1 to 5, comprising the steps of: Drawing a two-dimensional sketch of a single-arrow frame body of a three-dimensional double-arrow unit cell on a front-view reference plane, wherein the side lengths of the top surface and the bottom surface are d, the length of an inclined rod is l, the included angle between the inclined rod and a bottom rod is theta, drawing a midline outline of the front view according to the parameters d, l and theta, and carrying out bidirectional equidistant offset on the midline outline of the front view by a distance t/2 to obtain the two-dimensional sketch of the single-arrow frame body; Secondly, bi-directional stretching the two-dimensional sketch of the single-arrow frame body by a distance t/2, cutting a square with the side length and the thickness of t at the joint of the diagonal rod and the bottom rod to be used as a connecting section of a lattice structure, obtaining the single-arrow frame body, and then rotating the single-arrow frame body around an axis by an angle delta circumferential array to obtain a three-dimensional double-arrow unit cell; sequentially arranging a plurality of three-dimensional double-arrow single cells in a mode of connecting the top surface with a connecting section to obtain a single press-twisting unit, wherein the single press-twisting unit is linearly arrayed upwards, and the twisting directions of the press-twisting units are opposite; and fourthly, forming a three-dimensional double-arrow negative poisson ratio structure by the arrays in the transverse direction and the longitudinal direction in the plane.
7. The method of designing a three-dimensional double-arrow negative poisson ratio structure according to claim 6, wherein in the first step, after the midline outline of the front view is offset by a distance t/2 in a bidirectional equidistant manner, intersecting sketch lines are trimmed, and then a two-dimensional sketch of a single-arrow frame is obtained.
8. The method of designing a three-dimensional double-arrow negative poisson's ratio structure according to claim 6, the method is characterized in that the rotation angle delta in the second step is 90 degrees.

Description

Three-dimensional double-arrow negative poisson ratio structure and design method thereof Technical Field The invention relates to the technical field of mechanical negative poisson ratio metamaterial energy absorption, in particular to a three-dimensional double-arrow negative poisson ratio structure and a design method thereof. Background Along with the continuous iterative development of production science, engineering technology in various fields has changed gradually, the requirements on material science are higher and higher while production means are improved, the use space of traditional materials is gradually reduced, and even in some fields, the requirements on production technology cannot be met, so that metamaterial with supernormal mechanical properties needs to be developed and applied to engineering construction. The negative poisson material is used as one of the metamaterial, has abnormal mechanical property of expanding when contracting and stretching under pressure, and has excellent specific stiffness, specific strength, shearing resistance, impact resistance and sound absorption performance compared with the traditional material due to the special mechanical property. At present, common negative poisson ratio metamaterial structures comprise a concave structure, a chiral or anti-chiral structure, a rigid polygonal structure, a reentrant structure and the like. These negative poisson ratio metamaterials have played a vital role in the fields of vehicles, ships, aerospace, medical appliances and the like. At present, double-arrow negative poisson ratio metamaterials have been developed, but the research on three-dimensional double-arrow negative poisson ratio metamaterials is less, most of the existing double-arrow negative poisson ratio metamaterials do not have compression-torsion effects, the negative poisson ratio and the energy absorption effect are not obvious enough, and the stability of the structure under load is poor. In view of the above, the invention provides a three-dimensional double-arrow negative poisson ratio structure and a design method thereof, which have better mechanical properties and energy absorption effect, have larger range poisson ratio adjustability and stronger universality in practical application compared with the prior double-arrow negative poisson ratio metamaterial with the characteristics of compression torsion. Disclosure of Invention The invention aims to provide a three-dimensional double-arrow negative poisson ratio structure and a design method thereof, wherein the structure has the characteristics of compression torsion, better mechanical property and energy absorption effect, and has wider poisson ratio adjustability and stronger universality in practical application. In one aspect, the invention provides a three-dimensional double-arrow negative poisson ratio structure, which is formed by connecting a plurality of press-twisting units in a linear array in a three-dimensional space, wherein the press-twisting units are formed by connecting a plurality of three-dimensional double-arrow single cells in a torsion sequence, each three-dimensional double-arrow single cell is formed by vertically connecting two single-arrow frame bodies, the crossed vertexes of inclined rods of the two single-arrow frame bodies are integrally connected to form a top surface, the middle parts of bottom rods of the two single-arrow frame bodies are vertically connected to form a bottom surface, the outer sides of the crossed parts of each inclined rod and the bottom rod form a connecting tangent plane, and the top surfaces of the three-dimensional double-arrow single cells are fixedly connected with the adjacent connecting tangent planes of the three-dimensional double-arrow single cells in sequence. Preferably, the top surface and the bottom surface are cross planes, and the top surface and the bottom surface are parallel. Preferably, the length and width of the cross plane are equal. Preferably, the connection section is a rectangular plane, and the connection section is perpendicular to the top surface. Preferably, the rectangular plane is square. Preferably, the top surface is in seamless bonding or integral connection with the connection section. Preferably, the bottom surface is located at one side of the connecting line of the end parts of the two diagonal rods, which is close to the top surface, and two ends of the bottom surface are fixedly connected with the bottom ends of the diagonal rods through the bottom rods respectively. On the other hand, the invention provides a design method of the three-dimensional double-arrow negative poisson ratio structure, which comprises the following steps: drawing a two-dimensional sketch of a single-arrow frame body of a three-dimensional double-arrow unit cell on a front reference plane, wherein the side length of the top surface is d, the length of an inclined rod is l, the side length of the bottom surface is d, the incl