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COBEM 2023
27th International Congress of Mechanical Engineering
A New Family of Auxetic Beams: The Elliptical S-Chiral Design Investigation
Submission Author:
Antonio Avila , MG
Co-Authors:
Nathália Mello Mascarenhas Paixão, Paulo César de Matos Rodrigues, ALEXANDRE SCARI, Almir Silva Neto, Antônio Maia, Lázaro Donadon, Antonio Avila
Presenter: Nathália Mello Mascarenhas Paixão
doi://10.26678/ABCM.COBEM2023.COB2023-0832
Abstract
Auxetic metamaterials are man-made materials displaying a negative Poisson Ratio. The chiral metamaterials can support larger overall strains than the classic re-entrant auxetic shape. Thus, the objective of this work was to obtain the flexural elastic properties of a family of sandwich beams with a chiral elliptical S-shaped core. To reach the objectives of this work, finite element simulations were obtained and an experimental setup with a sandwich beam made of a circular S-shaped core was performed. The experimental results were compared to the simulated ones in order to validate the simulations. The experimental samples were fabricated using additive manufacturing with polyacid lactic as raw material. An increase in the aspect ratio (a/b) of the ellipse core led to an increase in sandwich beam flexural stif ness and a reduction in mass. Moreover, the highest value of the core shear modulus was achieved with the (a/b) ratio around 1.5, followed by a decrease as the aspect ratio increased. This seemingly paradoxical finding, where sandwich beam flexural stif ness increased while the core shear modulus decreased, can be explained by the design's contribution to increasing the core's moment of inertia. Additionally, normal stress profiles in the x-direction did not dif er significantly between the structures.
Keywords
metastructures, Sandwich beams, Auxetic Materials, Finite Element Method, Additive manufacturing
