Emergent mechanical properties of biomimetic exoskeletal metamaterials

Hossein Ebrahimi; Hessein Ali; Jeremy Stephen; Sanjay Dharmavaram; Ranajay Ghosh

doi:10.1117/12.2584345

22 March 2021 Emergent mechanical properties of biomimetic exoskeletal metamaterials

Hossein Ebrahimi, Hessein Ali, Jeremy Stephen, Sanjay Dharmavaram, Ranajay Ghosh

Proceedings Volume 11586, Bioinspiration, Biomimetics, and Bioreplication XI; 115860N (2021) https://doi.org/10.1117/12.2584345
Event: SPIE Smart Structures + Nondestructive Evaluation, 2021, Online Only

Abstract

Exoskeletons, such as scales on fishes and snakes were a critical evolutionary adaptation. Honed by millions of years of evolutionary pressures, they are inherently lightweight and yet multifunctional, aiding in protection, locomotion and optical camouflaging. This makes them an attractive candidate for biomimicry to produce high performance multifunctional materials with applications to soft robotics, wearables, energy efficient smart skins and on-demand tunable materials. Canonically speaking, biomimetic samples can be fabricating by partially embedding stiffer plate like segments on softer substrates to create a bi-material system, with overlapping scales. Recent investigations on their mechanics have shown that the origins of many of these behaviors are not merely due to load distribution but because of an intricate interplay of deformation, sliding and interfacial behavior. Such interplay give rise to property combinations that are typically not visible in the parent material of either the scales or the substrates. Here we review and present the origins of some of their fascinating behavior which include nonlinear and directional strain stiffening in both bending and twisting, dual nature of friction which combines both resistance as well as adding stiffness to motion, emergent viscosity in dynamic loading, and non-Hertzian contact mechanics. We will provide derivation of simple mathematical laws that govern structure- property relationships that can help guide design. We will also demonstrate possibilities in non-mechanical properties such as elementary structural coloration and topography influenced mass deposition. We conclude by providing perspectives of future development and challenges.

Conference Presentation

Citation Download Citation

Hossein Ebrahimi, Hessein Ali, Jeremy Stephen, Sanjay Dharmavaram, and Ranajay Ghosh "Emergent mechanical properties of biomimetic exoskeletal metamaterials", Proc. SPIE 11586, Bioinspiration, Biomimetics, and Bioreplication XI, 115860N (22 March 2021); https://doi.org/10.1117/12.2584345

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