Metamaterials with relative displacements in their microstructure: technological challenges in 3D printing, experiments and numerical predictions

3D printing technology has opened application perspectives which were difficult to imagine only few years ago. In this paper, we show how it is possible to design and print some microstructures in which relative displacements are allowed at micro-level. Some structural elements have been built in the aforementioned structures which can be confidently modeled as perfect pivots or as soft elastic connections. The obtained specimens can be regarded as constituted by very exotic materials, as forecast theoretically. We numerically study the behavior of pantographic structures including soft or nearly perfect pivots in large deformations, and we experimentally observe an enlarged elastic range and peculiar buckling mechanisms. The presented results are extremely promising: We consider now as proven that higher gradient metamaterials can be realized by using microstructures having micro-characteristic lengths of the order on tenth of millimeters.

metamaterials; pantographic microstructure; generalized continuum; second gradient theories

Metamaterials with relative displacements in their microstructure: technological challenges in 3D printing, experiments and numerical predictions Articles