Probing vibrational eigenmodes in diatom frustules via combined in silico computational study and atomic force microscopy experimentation

Abstract

Diatom frustules, the intricately structured algal silica exoskeletons, have remarkable mechanical properties and so are ideal candidates for various engineering applications. This study presents a comprehensive investigation of the eigenmode resonance frequencies of diatom frustules through the combination of in silico and experimental characterization. The predictions for the diatom resonance frequencies in the range of 1–8 MHz, which were made by COMSOL Multiphysics, were experimentally validated using the optical detection system of the atomic force microscope. Precise measurement of the resonance frequencies of thin miniature shells, such as diatom frustules, is pivotal in enabling their use for vibration-based sensing and optimal design of diatom-inspired micro-electro-mechanical system devices, which can facilitate effective energy absorption, vibration damping, and highly sensitive detection.

Natural Frequencies of Diatom Shells: Alteration of Eigenfrequencies Using Structural Patterns Inspired by Diatoms

“…The eigenfrequency scaling led to 1st eigenfrequency values between 3 MHz and 20 MHz, which were within the range of diatom eigenfrequencies obtained in other studies [18,19]. Thus, the simulation models can be seen as resilient.…”

“…Table 4. Material properties of the aluminum alloy AlSi10Mg assigned to the models of the present study compared to the material properties assigned to diatom models studied by Cvjetinovic et al [18].…”

“…In addition to the scale factor 1/η, a scale factor ϵ was defined to consider the different material properties with the aim to compare the obtained results to already published data on diatom eigenfrequencies. While in the present study, aluminum was specified as material, the Young's modulus, density, and Poisson's ratio vary from the values obtained for real diatom shells published by [18] (Table 4). Table 4.…”

“…with E p and E c representing the Young's modulus of the present study and obtained by [18], respectively, and ρ p and ρ c symbolizing the material densities, respectively. Thus, each eigenfrequency of a diatom-inspired dome models f p was scaled to receive an estimated 1st eigenfrequency value of a diatom shell f diatom :…”

“…However, the vibrational characteristics of diatoms have been less often investigated. First experimental studies on the vibrational eigenmodes of diatoms using atomic force microscopy have been carried out [18]. The 1st eigenfrequencies of the diatom shells were between 1-8 MHz.…”