Highly energy absorption capability of biomimetic thin-walled structures inspired by woodpecker beak integrated with turtle shell curvature

Energy absorbing structure is crucial for impact protection under complex loading conditions. This study proposes an efficient lightweight impact-protection structure with sinusoidal and circular thin-walled beams, inspired by the beaks of woodpeckers integrating with shells of turtles. The finite element simulations on compression and impact reveal that the structure undergoes progressive deformation as the amplitude increases. The analysis results show that both total energy absorption (EA) and specific energy absorption (SEA) are significantly influenced by the amplitude, with the maximum SEA reaching 6.75 J/g which is nearly 3 to 4 times higher than the conventional honeycomb structures. Additionally, the results also indicate that increasing the thickness of the structural walls can enhance the compression strength. However, this could lead to a higher total mass and reduced effective compression deformation, which in turn decreases SEA. This research offers a novel approach to designing lightweight protective structures for applications in energy absorption.