With the aid of commercial concrete material models, numerical simulation plays an increasingly important role in the analyses of dynamic responses of concrete structures subjected to intense dynamic loadings. Mesh-size dependency is a known problem of local material models used to simulate concrete due to strain softening, which is observed in numerous simulations. In this paper, the widely used regularization technique for quasi-static problems, smeared crack approach, is evaluated and proven to be ineffective for dynamic situations. To resolve the mesh-size dependency of concrete under dynamic loadings, the nonlocal formulation of the modified K&C (MKC) model proposed in our recent work is presented. The nonlocal MKC model is validated against four experiments, covering a wide range of stress/loading conditions, namely: Modified Split-Hopkinson Bar (spalling) test, Split-Hopkinson Tension test, Split-Hopkinson Pressure Bar test, and reinforce concrete beam subjected to blast loading. The numerical predictions are mesh objective and in good agreement with the corresponding experimental data.
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