Structured porous metamaterial

A metamaterial and structured technology, applied in additive processing, using stable tension/pressure to test material strength, processing and manufacturing, etc., can solve problems such as fragile

Inactive Publication Date: 2017-02-22
RMIT UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It was also noted that structures with higher porosity resulted in structures characterized by very thin junctions, making the structure prone to fracture

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0274] Example 1 – Cubic Elementary Cell with Spherical Cavity

[0275] Such as Figure 1A (A) and Figure 1B As shown in (A), the geometry of the basic cell for this exemplary 3D auxetic metamaterial is formed by generating a hollow spherical cavity inside a cube. Repeat each building cell to form Figure 1A (B) and Figure 1B The 3D honeycomb material shown in (B). Experimental metamaterial blocks were constructed by repeating nine building cells along three perpendicular directions and halving the cells at both ends in each direction. Individual specimens of blocks of 3D material were fabricated using 3D printing (ObjetConne x 350) with a silicone-based rubber material (TangoPlus) and support material.

[0276] According to the deformation mode after buckling, the representative volume element (RVE) contains as Figure 1A (C) and Figure 1B (C) shows the four building cells. From the ratio (R) of the diameter of the sphere to the length of the cube, two resulting geome...

example 2

[0288] Example 2 – Mechanism Analysis (Buckling Modes)

[0289] Numerical simulations were performed using the commercial finite element (FE) software package ABAQUS (Simulia, Providence, RI) to determine the mechanism of the observed auxetic behavior in the inventive metamaterial discussed in Example 1 .

[0290] Buckling analysis was performed using ABAQUS / standard solver and postbuckling analysis was performed using ABAQUS / explicit solver. Quadratic solid elements with medium precision (element type C3D10R with mesh scan seed size of 0.4mm) were used. The analysis was performed under uniaxial compression. The buckling modes with 3D alternating ellipsoidal modes from the buckling analysis were used as shape change or imperfection factors for nonlinear (large deformation) post-buckling analysis. Experimental results are used to validate the finite element model.

[0291] Figure 4 A comparison of the deformation process of the metamaterial along one direction is shown, fr...

example 3

[0294] Example 3 - Cubic elementary cell with ovoid shaped cavity

[0295] Such as Figure 6 As shown, to overcome the buckling disadvantage in Examples 1 and 2, the geometry of the basic cell for this exemplary 3D auxetic metamaterial is formed by creating a hollow ovoid cavity inside a cube. The designed ovoids included an 8% incompleteness in the shape of the spherical cavities used in the materials discussed in Examples 1 and 2. In addition, the matrix of the basic units in the material is such that the central long axis of the ovoid cavity of each basic unit is perpendicular to the central long axis of the ovoid cavity of each adjacent basic unit. Thus, in effect, the mode of the buckling mode seen in Example 1 and Example 2 is introduced into the cavitation mode of the metamaterial of this embodiment. The porosity of the unit cell of Example 1 was found to be 87.4% and that of Example 2 was 87.2%.

[0296] Figure 5 A direct comparison of the nominal stress-strain cu...

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Abstract

The invention relates to a structured porous metamaterial. The structured porous metamaterial comprises a three-dimensional matrix of at least one repeating base unit, wherein the matrix is formed from an array of at least eight base units, each base unit comprises a platonic solid including at least one shaped void, each base unit has void geometry tailored to provide a porosity of between 0.3 and 0.97; or provide the metamaterial with a response comprising at least one of a Poisson's ratio of 0 to -0.5 when under tension and compression; or negative linear compression (NLC), negative area compression (NAC), zero linear compression (ZLC), or zero area compression (ZAC) behaviour when under pressure.

Description

technical field [0001] The present invention generally relates to three-dimensional (3D) structured porous metamaterials having a specific mode of deformation (pattern) under an applied load, and more specifically, to having a negative or zero Poisson's ratio and / or zero or negative compressibility (NC) 3D structured porous metamaterials. Background technique [0002] The purpose of the following discussion of the background art is to facilitate the understanding of the present invention. It should be understood, however, that such discussion is not an admission that anything referred to was published, known or part of the common general knowledge as at the priority date of the application. [0003] The Poisson's ratio of a material is defined as the negative of the ratio of the lateral strain to the axial strain of the material under uniaxial tension or compression. Most materials have a positive Poisson's ratio, so the material expands laterally under compression and con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B5/18
CPCC08J2300/26B29C44/357C08J9/00B29C64/10B33Y70/00B33Y10/00B33Y80/00B29K2083/00C08J2205/04C08J2383/04G01N3/08
Inventor 谢亿民沈建虎周世伟黄晓东
Owner RMIT UNIVERSITY
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