UC San Diego

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