Two natural toughening strategies may inspire sustainable structures | Scientific Reports

The condition for crack deflection was developed by applying classic fracture mechanics to laminates with variable layer thickness and stiffness, and was used in investigating two biologically inspired laminates.

We found that the cuticle-like laminate deflects cracks via a decrease in the layers modulus in the crack direction, whereas the spicule-like laminate achieves this behavior by increasing the layers thickness.

A wider picture is obtained by extending the thickness and stiffness grading ranges beyond those of the biological examples. We show that the grading approach can be used in synthetic laminate design to reach higher resilience (in a critically vulnerable direction) than that of a uniform laminate, without adding reinforcing material, or, alternatively, to retain the desired resilience but with significantly less material.

Both grading types enhance the structural sustainability by reducing material waste and structural weight, and may potentially achieve better durability and material efficiency.