Two-scale and full-scale analyses of elastoplastic honeycomb blocks subjected to flat-punch indentation

In this study, we perform comparative two-scale and full-scale analyses of elastoplastic regular hexagonal honeycomb blocks subjected to in-plane flat-punch indentation. Zigzag and armchair types of cell arrangements are considered for the blocks; relatively thick cell walls are assumed to focus on the effect of cell wall yielding rather than cell wall deflection. For the two-scale analysis, the fully implicit homogenization scheme developed by Asada and Ohno [Asada, T., Ohno, N., 2007. Fully implicit formulation of elastoplastic homogenization problem for two-scale analysis. International Journal of Solids and Structures 44, 7261–7275] is rebuilt by introducing half unit cells to halve the analysis domains in unit cells. For the full-scale analysis, three cell sizes are considered. It is shown that the two-scale analysis provides no apparent dependence on the two types of cell arrangements because of their equivalence under in-plane loading, whereas the full-scale analysis reveals that the local deformation in honeycomb blocks is highly dependent on cell arrangement. Nevertheless, the two-scale analysis is found to be successful in predicting the indentation load-displacement relation and the macroscopic localization direction in honeycomb blocks.