Multiscale modelling and simulation of the deformation and adhesion of a single gecko seta

Abstract

A 3D multiscale model is presented which describes the adhesion and deformation of a gecko seta. The multiscale approach combines three models at different length scales: at the top level, on the order of several micrometers, a nonlinear finite element beam model is chosen to capture the branched microstructure of the gecko seta. At the intermediate level, on the order of several nanometers, a second finite element model is used to capture the detailed behaviour of the seta tips, the so-called spatulae. At the lowest level, on the order of a few angstroms, a molecular interaction potential is used to describe the van der Waals adhesion forces between spatulae and substrate. Coarse-graining techiques are used to bridge the scale between the model levels. To illustrate and validate the proposed gecko seta model, numerical pull-off simulations are shown and compared to experimental data from the literature.

Keywords:

• computational contact mechanics
• interatomic potential
• gecko adhesion
• geometrically exact beam theory
• multiscale modelling
• nonlinear finite element methods

Acknowledgements

The author is grateful for the support of Peter Wriggers and thanks the students Shujun Lu and Friederike Loerke for their help on the model implementation.