Mechanical Performance of Auxetic Structures

Published: 09-06-2020| Version 1 | DOI: 10.17632/43cz8mmnry.1
Contributor:
Gregory Gibbons

Description

This data is mechanical test data collected for a range of Auxetic structures built using metal 3D Printing (laser-Powder Bed Fusion). The work investigated the relationship between the design of the auxetic structures (length of the vertical strut (H), length of the re-entrant struts (L), strut thickness (t) and re-entrant angle (ϴ) . Testing was performed in compression, using Digital Image Correlation to measure the strain and deformation of the unit cells forming the auxetic structures. Auxetics were manufactured with density >99.3%, with porosity level and geometrical accuracy dependent on strut orientation, with better quality achieved for struts aligned nearest to the vertical Z-axis. The auxetics were highly anisotropic, with minimal variation (1.02±0.07 GPa) in Ex (perpendicular to the vertical strut) but large variation in Ey (4.4±0.1 GPa). σx and σy varied similarly across all structures (σ ̅x = 45±6, σ ̅y = 45±9). νxy, (perpendicular to the vertical strut) was found to not vary considerably with geometry, whereas νyx was found to vary considerably. Vertical strut height and re-entrant angle have no statistical effect on mechanical performance. Ex is determined by strut thickness (t), Ey by re-entrant strut length (L). σx and σy are controlled by t and L. νxy is strongly determined by L and νyx is controlled weakly by t. Mechanism for deformation in x compression is a combination of vertical strut stretching, re-entrant strut compression, bending and hinging; whereas for y compression, deformation results from a combination of vertical strut compression and re-entrant strut stretching and bending.

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