Damage morphology of mechanical metamaterials using self-similar forms

Abstract

Metamaterials can develop new properties by controlling their shape. The structure imitating Menger sponge, the self-similar form, has the property that the stress concentration area changes depending on the complexity of the structure. These properties are potentially applicable as metamaterials to control the damage initiation area. In this study, structures imitating H-shaped fractals and Sierpinski gaskets were fabricated, and their stress concentration characteristics were investigated with experiment and finite element method. Artificial design was needed because the original self-similar forms of H-shaped fractal and Sierpinski gasket have areas of zero length or thickness. In the case of Sierpinski gasket, the stress concentration area did not change within the design of this study, however, in the case of H-shaped fractals, the property of changing the stress concentration area was observed when the structures were designed so that the similarity was maintained.