Open AccessTesting of Auxetic Materials Using Hopkinson Bar and Digital Image Correlation
Author(s) -
Tomáš Fíla,
Petr Zlámal,
Jan Falta,
Tomáš Doktor,
Petr Koudelka,
Daniel Kytýř,
Marcel Adorna,
Jutta Luksch,
Michaela NeuhäuserovTomá,
Jaroslav Valach,
Ondřej Jiroušek
Publication year - 2018
Publication title -
epj web of conferences
Language(s) - English
Resource type - Journals
eISSN - 2101-6275
pISSN - 2100-014X
DOI - 10.1051/epjconf/201818302045
Subject(s) - auxetics , digital image correlation , split hopkinson pressure bar , materials science , strain gauge , composite material , bar (unit) , poisson's ratio , structural engineering , poisson distribution , strain rate , mathematics , physics , statistics , meteorology , engineering
In this paper, a split Hopkinson pressure bar (SHPB) was used for impact loading of an auxetic lattice (structure with negative Poisson’s ratio) at a given strain-rate. High strength aluminum and polymethyl methacrylate bars instrumented with foil strain-gauges were used for compression of an additively manufactured missing-rib auxetic lattice. All experiments were observed using a high-speed camera with frame-rate set to approx. 135.000 fps. High-speed images were synchronized with the strain-gauge records. Dynamic equilibrium in the specimen was analyzed and optimized pulse-shaping was introduced in the selected experiments. Longitudinal and lateral in-plane displacements and strains were evaluated using digital image correlation (DIC) technique. DIC results were compared with results obtained from strain-gauges and were found to be in good agreement. Using DIC, it was possible to analyze in-plane strain distribution in the specimens and to evaluate strain dependent Poisson’s ratio of the auxetic structure.