A kirigami metamaterial with adjustable auxetic properties under large stretch and its design method

Abstract

A kirigami metamaterial with adjustable auxetic properties under large stretching amount and its design method. The kirigami metamaterial is composed of a plurality of square unit cells arranged in an orderly manner, and the multiple unit cells are periodically, Gradient or irregular arrangement, the corresponding kirigami metamaterials have uniform auxetic properties, gradient auxetic properties and specified non-uniform auxetic properties respectively. The design method is as follows: firstly, the heuristic design of the unit cell configuration is obtained by using the structural optimization method and fully considering the out-of-plane deformation constraints. Secondly, geometric reconstruction and parameter modeling are performed on the optimization results obtained in the above steps, and the auxetic characteristics under different geometric parameters are obtained. Finally, a variety of unit cell configurations are arranged according to a specific arrangement order to construct kirigami metamaterials. By modifying the notch parameters, the present invention can realize a variety of auxetic change trends that can be adjusted with the stretching amount; compared with the existing kirigami metamaterials, the present invention has obvious advantages in structural design, application range and application prospect Advantage.

Description

technical field [0001] The invention belongs to the field of metamaterials, and relates to a kirigami metamaterial with adjustable auxetic properties under a large stretching amount and a structure design method thereof. Background technique [0002] Kirigami metamaterials are a type of mechanical metamaterials that obtain specific equivalent mechanical properties through the orderly (periodic, gradient, irregular) arrangement of notches on the thin sheet structure. Advantages such as waste and fast load response. [0003] The auxetic kirigami metamaterial produces transverse expansion deformation under the action of longitudinal tensile load, and this auxetic property can be expressed as the negative value of the ratio of the average transverse deformation to the longitudinal elongation. At present, the existing auxetic kirigami metamaterials are designed based on artificial experience or by trial and error, and the arrangement of notches included has mirror-image symmetry...

AI Technical Summary

Problems solved by technology

[0004] When the above-mentioned auxetic kirigami metamaterials elongate beyond a certain percentage of the sample size (usually less than 10%), unstable out-of-plane buckling deformation occurs, resulting in failure to maintain the specified auxetic properties

On the one hand, this is due to the small out-of-plane stiffness of the sheet structure, and on the other hand, due to the fact that the preset notch and the notch layout reduce the out-of-plane stiffness of the local area

At the same time, the existing auxetic kirigami metamaterials are prone to high strain (or high stress) under large stretching, leading to the failure or even destruction of the matrix material, which affects the reliability, deformation recoverability and equivalent performance of the metamaterial. cause negative impact

The performance deficiencies in these two aspects limit the practical application of kirigami metamaterials

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