The dynamic behaviors of cellular silica were experimentally investigated. The factors of cell size, cell volume fraction, strain rate, and loading mode were analyzed systematically. Under dynamic shearing, the shear localization in nano-cellular silica could be significantly suppressed. Under dynamic indentation, the effective indentation resistance of nano-cellular silica could be higher than that of solid silica. These unique phenomena of nano-cellular silica could be attributed to the local hardening caused by the fast compaction of the small cells. Based on dimensional and theoretical analyses, two models were developed to describe the cell size effect on the deformation zone size in dynamic shearing and on the effective indentation resistance in dynamic indentation, respectively. They agree well with the experimental results. A diagram of cell size effect, accounting for the three factors of cell size, cell volume fraction, and kinetic energy, was drawn to distinguish the nano-cellular materials from the regular cellular materials

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The dynamic indentation behaviors of monolithic silica nanofoams of various porosities are investigated. When the pore size is on the nm scale, as the porosity increases, despite the decrease in mass density, the resistance offered by silica nanofoam to dynamic indentation is maintained at a high level, higher than the resistance of solid silica or regular porous silica. This phenomenon is related to the fast collapse of nanocells, which produces a locally hardened region and significantly increases the volume of material involved in impact energy dissipation.