Energy Absorption Strategy in Biological and Bioinspired Tubular and Lamellar Structures

Energy absorption capability is critical in biological and engineering materials, particularly when subjected to extreme compressive and impact loading. The cellular structure is recognized for its effectiveness in energy absorption, dissipating energy through material plasticity and structural collapsing, leading to significant densification. In the current work, we demonstrate how natural biological materials, like horns and hooves, control crack generation and propagation through lamellar and tubular structural designs. Interestingly, these natural materials achieve substantial energy absorption without creating large void volumes, relying on generating microcracks and interfaces. Inspired by these biological tissues, lamellar and tubular structures were fabricated via multi-material polymer 3D printing techniques. The resulting bioinspired structures exhibit an impressive energy absorption density of ~18.75 kJ•kg-1, comparable to the performance of metal foams and bioinspired honeycomb structures. Introducing soft-hard interfaces in lamellar and tubules notably enhances impact energy absorption by approximately 167% compared to solid structures printed with a single material. The bioinspired structures maintain structural integrity even under high strain rate impacts of around 2000 s-1, showcasing resistance to deformation and catastrophic failure. This bioinspired approach allows for a combined energy absorption capability in quasi-static compression and high strain-rate impact scenarios.