Abstract
The cuttlebone is a rigid buoyancy tank which enables the cuttlefish to maintain a fixed position in water with minimal effort. It must be strong enough to withstand hydrostatic pressure and lightweight in order not to sacrifice buoyancy. In this study, structure and mechanical properties of cuttlebone obtained from Sepia pharaonis were investigated. Micro-structural features of cuttlebone were characterized by stereoscope, micro-CT, and SEM. The cuttlebone, mainly made of CaCO3 in aragonite form and chitin, had a unique cellular architecture. Parallel lamellae called septum and supporting pillars formed chambers with spacing varying from 200 to 400 μm. Numerous thin sheets between pillars within a chamber were observed. Mechanical properties were evaluated by compression tests on dry and fresh samples in three anatomical directions. Results can be modeled as cellular solids with strong dependence on relative density. Deformed samples were examined by SEM at progressive stages and toughening mechanisms were discussed.