Geometric design and mechanical properties of foldcores based on the generalized Resch patterns

Foldcores have been regarded as a promising alternative to the conventional honeycomb core in lightweight sandwich structures, especially in the aerospace sector. Current research on foldcores is mainly focused on the Miura pattern. However, the Miura-based foldcores provide only edge-based bonding interfaces to the skins, which may cause a weak core-skin bonding strength. In this paper, foldcores based on the generalized Resch patterns are researched, which can provide face-based bonding interfaces. The content of the paper is threefold. First, a generic geometric design method to generate the geometries of foldcores based on the generalized Resch patterns is proposed. Second, the finite element procedures to model foldcores under quasi-static compression and shear are developed and validated through experimental results. Third, a parametric study on the quasi-static mechanical properties of foldcores of different types and with different geometries is performed. It is shown that foldcores based on the hexagonal pattern have the highest peak stress and energy absorption capacity among the three types of generalized Resch patterns, and the multi-layered foldcore in general outperforms the single-layered counterpart. When compared with the Miura-based foldcores, the generalized Resch-based foldcores assume better performance in the energy absorption capacity.