A Comparative study of the mechanical properties of the bio-inspired overlapped scales fabricated by 3D printing

Abstract

The extreme contrast in stiffness between the hard scales and the surrounding soft issue of animals produces an unusual and attractive mechanism that inspires the designs of biomimetic armor. Despite the growing interest, there are few guidelines for the choice of material, optimal thickness, size, shape and arrangement of the protective scales. Here, we designed six biomimetic armors through simplifying and normalizing the biological armor structures while retaining the main features. We fabricated these structures by 3D printing technology and performed a comparative study of their mechanical properties. We found that the interactions between the adjacent scales significantly enhanced the mechanical performance. We investigated the effect of two important geometrical parameters, the overlapped depth ratio k and slanted angle θ, on the mechanical properties of the composite structures. Moreover, we analyzed the k values for the scales from different body parts of the herbivorous and carnivorous teleost. The optimized designs with different k-values were identified in different parts of the teleost. This study yields new insights into the mechanisms of the overlapped structures and suggests new designs for biomimetic protective systems.