Three-dimensional controllable pulling and expanding multi-cell structure based on 3D printing

Abstract

The invention discloses a three-dimensional controllable pulling and expanding multi-cell structure based on 3D printing. The three-dimensional structure can be obtained by two different signal cells by means of space array; the first single cell is obtained in the manner that two two-dimensional chiral honeycomb single cells rotate by 90 degrees in space to be fixedly connected together; the second single cell is obtained in the manner that there two-dimensional chiral honeycomb single cells rotate by 60 degrees and 120 degrees in space to be fixedly connected together; and each two-dimensional chiral honeycomb single cell is obtained in the manner that two crossed and fixedly connected rods are subjected to mirror symmetry two times. The multi-cell material has the negative poisson's ratio property, when the multi-cell material is compressed in one direction, the multi-cell material can be shrunken inwards in the other two directions, and therefore the structure is more compact, and the structure can more effectively resist the compression load. Besides, by changing the slenderness ratio and the inclination angle of the first rod and the second rod, the elastic performance of the multi-cell material is adjusted.

Description

technical field [0001] The invention relates to an auxetic structure, in particular to a controllable three-dimensional auxetic multicellular structure based on 3D printing. Background technique [0002] Poisson's ratio refers to the ratio of the absolute value of the transverse normal strain to the axial positive strain when the material is under unidirectional tension or compression, also called the transverse deformation coefficient, which is an elastic constant reflecting the transverse deformation of the material. Its calculation formula is: [0003] [0004] Among them, ε x is the transverse normal strain of the material, ε y is the axial normal strain of the material. [0005] The value range of Poisson's ratio is -1 to 0.5. The well-known traditional materials generally have a positive Poisson's ratio, that is, when the material is stretched in the axial direction, it will shrink in the transverse direction, or when it is compressed in the axial direction, it w...

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Problems solved by technology

There are two main types of existing 3D auxetic cellular structures: 3D concave hexagonal cellular structures and 3D double arrow cellular structures. These two 3D cellular structures have auxetic effect and Poisson’s ratio is controllable , but the stiffness of these two structures is relatively small

Lu et al. proposed a three-dimensional cross-chiral polycellular structure based on two-dimensional cross-chiral honeycomb. Although compared with the previous two structures, this structure has auxetic effect and higher stiffness, but the controllability of the model is limited. The change range of loose ratio is only -1~0

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