The bone of the cuttlefish has many fascinating properties: It is very resistant to isostatic pressure at a relative density of only 7% and when it fails, it rarely fails catastrophically. It is used by the cuttlefish as a buoyancy tank to rise and sink by pumping water in or out of the structure. The microstructure of the cuttlebone consists of horizontal plates (septa) which are connected by thin corrugated lammelas. Due to the relatively good mechanical properties compared to its density, it is worth having a closer look at the mechanisms appearing within this material.
In this contribution, the cuttlebone is investigated in detail by means of micro computed tomography. Information about density, local lamella thickness and orientation are derived. The local data is used to quantify the structure globally in descriptive statistics. Subsequently, the mechanical properties of the structure is modeled directly on the CT data using the immersed boundary finite element approach. In contrast to common FEA approaches, this method makes meshing unnecessary and enables to include very fine structures or defects into the simulation.
The results give new insights into the orientation, distribution and wall thickness of the lammelas connecting the well-defined horizontal plates of the structure. Mechanical simulations show stress distributions, and highlight critical regions of the structure. Understanding the functional morphology of the cuttlebone together with recent advances in additive manufacturing techniques might allow construction of artificial bioinspired low density structures with increased structural strength.