Journal of Materials Science and Engineering with Advanced TechnologyAuthor's: Alejandro Gutiérrez, Richard Gordon and Lilian P. Dávila
Pages: [105] - [134]
Received Date: March 26, 2017; Revised April 28, 2017
Submitted by:
DOI: http://dx.doi.org/10.18642/jmseat_7100121810
The ubiquitous diatoms, single-celled algae with porous silica frustule (shell) morphology and features spanning multiple length scales, offer a promising foundation to convert knowledge of biological structures into novel design techniques. Diatom frustules are often found in nature with distinct deformation patterns suggesting the involvement of mechanical interactions in their morphogenesis. Understanding this phenomenon can lead to potential manufacturing techniques based on the micromanipulation of bio-inspired structures. In this study, the mechanics of centric diatom frustules was investigated using the finite element method (FEM) in combination with morphology and material properties obtained from scanning electron microscopy (SEM) and mechanical tests respectively. SEM micrographs of a marine diatom, Coscinodiscus sp., have allowed the classification of specific deformation patterns frequently observed on these frustules. To elucidate the nature of these deformations, a computer aided design (CAD) model approximating a centric diatom frustule was created. Using shear-deformable frustule finite elements and diatom-specific Young’s modulus, critical buckling load and modal analysis of the diatom model were performed to investigate possible correlations of the deformation modes with observed morphologies. Results reveal that the first ten deformation modes correlate noticeably well with deformation patterns observed through SEM. Additionally, FEM models were used to study the relation between diatom morphology and mechanical behaviour. A quadratic relation was established between frustule pore size and critical buckling load as well as a cubic relation between frustule thickness and critical buckling load, reported for the first time in this study. The findings in this research provide insights into the mechanical response of diatom frustules that can aid the realization of tailored properties in new bio-inspired materials, in particular for nanotechnology applications, but also for advanced metamaterials and optomechanical devices.
diatoms, frustule deformation, microscale, nanoscale, biostructures, porous silica.
