Bending stiffness tunability of biomimetic scale covered surfaces via scales orientations

Abstract

Biomimetic fish scale structures on soft substrates can provide tailorable and tunable mechanical stiffness. When distributed over a reference 2D flat substrate, their simultaneous in-plane and out of plane sliding kinematics give rise to highly intricate geometrically dictated nonlinear and asymmetric behavior. Existing studies which focus on beam with filamentous structures, only partially reveal these complexities. Using finite element based numerical simulations, in this work we reveal the kinematics and bending mechanics of these structures. Scales are treated as stiff and rigid with flat plate-like geometry. We discover five distinct engagement patterns determined by the dihedral angles and overlap of the scales. These complexities are reflected in the multi-axial moment–curvature responses for bending revealing a rich landscape of tailorable and variable stiffness that can be exploited to create new types of flexible substrates which can significantly impact evolving frontiers of segmented armors, soft robotics, rehabilitation engineering and medium scale aerospace vehicles.