High Strain Rate Behaviour of Auxetic Cellular Structures

High Strain Rate Behaviour of Auxetic Cellular Structures

Nejc Novak, Matej Vesenjak, Shigeru Tanaka, Kazuyuki Hokamoto, Baoqiao Guo, Pengwan Chen, Zoran Ren

Abstract. Auxetic cellular structures are modern metamaterials with negative Poisson’s ratio. The auxetic cellular structures build from inverted tetrapods were fabricated and experimentally tested under dynamic loading conditions to evaluate the effect of strain rate on their deformation mode. The Split-Hopkinson Pressure Bar (SHPB) apparatus was used for testing at strain rates up to 1,250 s-1, while a powder gun was used for testing at strain rates up to 5,000 s-1. The homogeneous deformation mode was observed at lower strain rates, while shock deformation mode was predominant at higher rates. The results have shown that the strain rate hardening of analysed auxetic specimens is prominent at higher strain rates when the shock deformation mode is observed, i.e. when most of deformation occurs at the impact front. Relevant computational models in LS-DYNA were developed and validated. A very good correlation between the computational and experimental data was observed.

Keywords
Cellular Structures, Auxetic Materials, High Strain Rate, Experimental Testing, Computational Simulations

Published online 7/30/2019, 6 pages
Copyright © 2019 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Nejc Novak, Matej Vesenjak, Shigeru Tanaka, Kazuyuki Hokamoto, Baoqiao Guo, Pengwan Chen, Zoran Ren, High Strain Rate Behaviour of Auxetic Cellular Structures, Materials Research Proceedings, Vol. 13, pp 25-30, 2019

DOI: https://doi.org/10.21741/9781644900338-4

The article was published as article 4 of the book Explosion Shock Waves and High Strain Rate Phenomena

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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