Effect of structurally-induced lateral confinement on split Hopkinson pressure bar test specimens of concrete-like materials
1 School of Civil Engineering, The University of Sydney Building J05, Sydney NSW 2006, Australia
2 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M13 9PL, UK
a Corresponding author: firstname.lastname@example.org
Published online: 7 September 2015
In dynamic testing of concrete-like materials, there is a need in distinguishing structural effects from genuine strain-rate effects. In this paper, this generic problem is studied by numerical simulations based on a phenomenological material model available in the commercial finite element (FE) code Abaqus. The numerical results show that the increase of the dynamic increase factor (DIF) with the increase of strain-rate in concrete-like materials in a Split Hopkinson Pressure Bar (SHPB) test is a phenomenon related not only to material strain-rate effects but also to structural effects. It was found that dilation, surface friction and lateral inertia cause lateral confinement, which enhances DIF when the strain-rate is greater than a transition strain-rate in the order of 102 s−1. Although, genuine strain-rate effect may exist as suggested by meso-scale simulations in previous investigations, the findings in this study show that structural effects have a significant contribution to the increase of DIF, and therefore, it is necessary to correctly calibrate existing phenomenological models and interpret the results obtained from split Hopkinson pressure bar (SHPB) tests.
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