Effects of loading rate on the mechanical behavior of a natural rigid composite

The effects of loading rate variations on the stress–strain behavior, failure mechanisms, fracture modes, and energy-dissipating capability of the spicules of the sponge Euplectella aspergillum have been investigated. Comparisons were made with similar measurements on a silicate glass. It was concluded that the very thin (5–10 nm) organic layers that are interspersed with thicker layers of hydrated silica in the concentric ring structure of the spicules strongly influence all aspects of the mechanical behavior.