Axial Low-Velocity Impact of Sandwich Columns with Aluminum Face-Sheets and Hexagonal Honeycomb Core

The dynamic behavior of sandwich columns with aluminum face-sheets and hexagonal honeycomb core under axial low-velocity impact is investigated experimentally and theoretically. In the impact tests, two typical competing cases of deformation, i.e., core shear-curling (CS-Cu) and local denting-plastic hinge (LD-PH), were observed following the first-order or higher-order global buckling. The deformation process, permanent deformation, cushioning property, energy dissipation efficiency, and factors affecting the competition of CS-Cu and LD-PH were compared and discussed in detail. It is found that, if CS-Cu occurs instead of LD-PH, an axially impacted sandwich column may perform better in both cushioning and efficiently dissipating residual energy. The theoretical analysis is carried out by extending the existing quasi-static global buckling theory of sandwich columns. A good agreement between the oscillatory plateau on the measured force-time curve and the predicted critical plastic global buckling load is found for the strain rate-insensitive face-sheet material.