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Experimental and computational evaluation of tensile properties of hexa- and tetra-chiral auxetic cellular structuresFriday (09.10.2020) 10:00 - 10:20 Room 1
Auxetic cellular materials are modern metamaterials with a negative Poisson's ratio, i.e., they become wider when stretched and thinner when compressed. Such unique deformation behavior is made possible by their particular internal structure, which is usually fabricated utilizing additive manufacturing technologies. This work describes the analysis of hexa- and tetra-chiral auxetic cellular structures.
The samples of auxetic structures were fabricated from two different materials (aluminum and stainless steel) using the selective laser sintering (SLS) method. All samples had equal dimensions. The samples were subjected to experimental tensile tests to determine their quasi-static mechanical properties. The results of the experimental tests were further used to build and validate the equivalent computational models in terms of mechanical properties and deformation behavior, observing the stress- and the Poisson's ratio-strain relationships.
The results show that the hexa- and tetra-chiral auxetic cellular structures have different deformation modes. The hexa-chiral auxetic cellular structures experience crushing in shear plane, while the tetra-chiral auxetic cellular structures fail localy in one layer of the sample. The newly developed computational models offer a possibility for further optimization of the chiral geometry design to determine the best-suited relation between the auxetic effect, stiffness, and failure strain for a specific application.