Mechanical Simulation of a Diatom Frustule Structure

Diatoms possess intricately complicated nanopatterned silica outer shells, the so called frustules. Due to their excellent three-dimensional (3D) nanostructures, diatom frustules have attracted attentions from many fields to look for potential applications, such as structural material design, light harvesting, photonics, molecular separation and bio-sensing. However, the mechanical property of frustule, especially the role of each single portion that structures a frustule, need to be clearly examined in order to provide a scientific support to frustule utilization. The reported work uses the Finite-Element (FE)-based simulation to investigate the relative mechanical properties of the frustule of the diatom Coscinodiscus sp. as compared with reference non-frustule structures. A three-dimensional model for the three featured layers of this frustule and a simplified model for its girdle band are built with the assistance of ABAQUS. A basic-cell concept is suggested; and the comparative results of several simulation groups are reported. The numerical results indicate that the seven-unit-cell model is able to catch the essential mechanics of the Coscinodiscus sp. frustule under pressure and that the layered and porous structure of this frustule can effectively resist pressure.