Mechanical behavior of biomimetic surface scales

Examining the evolutionary response of diverse biological species to counter the existential threats from hostile environmental and predatory landscape can shed light on the principles of protective system design. In this context, dermal scales, prevalent across biological groups imply their versatility in boosting survivability and providing multifunctional advantages for the species. Here, we investigate the nonlinear mechanical effects of biomimetic scale-like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial distribution of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking the well-known material level complexities. Our study shows biomimetic sclaes are capable of exhibiting an additional higher spatial scale of complex mechanical effects in addition to those at the lower meso level often due to the topology of constituents and the even lower constituent level which are often of purely material origin