On compressive properties of composite sandwich structures with grid reinforced honeycomb core

In the present study, periodical grids were selected to reinforce soft honeycomb cores of sandwich structures. The grid reinforced honeycomb core can be considered as a combined core with multi-level lattice configuration. In-plane compression tests were carried out to investigate the mechanical properties of carbon fiber sandwich with combined core. Experimental results indicated that the combined core sandwich specimens provided increased stiffness, specific stiffness, energy absorption and critical load, which were higher than the sum of honeycomb core sandwich specimens and grid core sandwich specimens. In addition, a Finite Element Method (FEM) model was proposed to calculate the critical buckling load of the combined core sandwich structures. The effects of core heights, honeycomb-wall thickness and face-sheet thickness on the critical buckling loads of the combined core sandwich structures were examined. The aforementioned experimental and numerical results indicated that the present sandwich structure with grid reinforced honeycomb core could provide improved structural properties for engineering structures.