Mechanical analyses on the digital behaviour of the Tokay gecko (Gekko gecko) based on a multi-level directional adhesion model.
This paper proposes a multi-level hierarchical model for the Tokay gecko (Gekko gecko) adhesive system and analyses the digital behaviour of theG. geckounder macro/meso-level scale. The model describes the structures ofG. gecko's adhesive system from the nano-level spatulae to the sub-millimetre-level lamella. TheG. gecko's seta is modelled using inextensible fibril based on Euler's elastica theorem. Considering the side contact of the spatular pads of the seta on the flat and rigid substrate, the directional adhesion behaviour of the seta has been investigated. The lamella-induced attachment and detachment have been modelled to simulate the active digital hyperextension (DH) and the digital gripping (DG) phenomena. The results suggest that a tiny angular displacement within 0.25° of the lamellar proximal end is necessary in which a fast transition from attachment to detachment or vice versa is induced. The active DH helps release the torque to induce setal non-sliding detachment, while the DG helps apply torque to make the setal adhesion stable. The lamella plays a key role in saving energy during detachment to adapt to its habitat and provides another adhesive function which differs from the friction-dependent setal adhesion system controlled by the dynamic ofG. gecko's body.
Department of Precision Machinery and Precision Instrumentation , University of Science and Technology of China , Hefei 230026, People's Republic of China ; Institute of Advanced Manufacturing Technology , Hefei Institutes of Physical Science, Chinese Academy of Sciences , Changzhou 213164, People's Republic of China.
Xuan
X
Wu
Institute of Advanced Manufacturing Technology , Hefei Institutes of Physical Science, Chinese Academy of Sciences , Changzhou 213164, People's Republic of China.
Xiaojie
0000-0002-6906-1587
X
Wang
Department of Precision Machinery and Precision Instrumentation , University of Science and Technology of China , Hefei 230026, People's Republic of China.
Tao
T
Mei
Institute of Advanced Manufacturing Technology , Hefei Institutes of Physical Science, Chinese Academy of Sciences , Changzhou 213164, People's Republic of China.
Shaoming
S
Sun
biomimetics; digital hyperextension; directional adhesion; gecko