Study of adhesion mechanism in gecko’s foot hair by FEM

Abstract

“Original research ideas can be conceived from the experiences of biological evolution” is the main reason why bio-adhesion systems attract global research interest in science and technology in recent years. However, one significant drawback of the existing simulation models is that viscoelasticity was not taken into consideration even though such systems usually consist of fibrillar structures, such as gecko’s foot hair, and the influence of viscoelasticity is significant. The present study focuses on investigation of the adhesive phenomenon of gecko with viscoelasticity using the finite element method. By simplifying a single spatulae as a flat-ended cylinder in contact with a rigid substrate, a model is devised to study the critical radius under which the stress becomes uniform for the adhesive structure. Furthermore, viscoelasticity is taken into consideration instead of elasticity. Roughness is also considered to see how it impacts on imperfect adhesion. The results obtained shows the critical radius is in agreement with theoretical calculations and experimental observation. Moreover, it has also been illustrated that materials with viscoelasticity is much easier to adhere.