Bioinspired Hierarchical Diamond Triply Periodic Minimal Surface Lattices with High Energy Absorption and Great Damage Tolerance

Porous solids are widely utilized in natural and engineering systems due to their exceptional specific mechanical response and customizable properties. However, lightweight cellular solids often undergo severe localized deformation, resulting in catastrophic failure. This limitation undermines their damage resistance, thereby limiting their use primarily within small strain regimes. To address this issue, we drew inspiration from the unique structural features and damage-tolerant characteristics of the knobby starfish, leading us to the design of hierarchical diamond–triply periodic minimal surface (TPMS) lattices on two levels. We carried out a thorough examination of their mechanical behaviors, energy absorption, and damage tolerance using both experimental methods and finite element models. The designed hierarchical diamond lattices displayed stable elastoplastic-like deformation across large strain, along with excellent damage resistance, maintaining a stiffness and strength of over 57% of the initial value after four cycles of compression. Simulations aligned well with experimental results, showing a progressive transition in the deformation behavior of the designed lattices from bending-dominated to stretching-dominated as the thickness of the micro-lattice increased. However, there are no significant changes in the deformation behavior for the shear modulus. Overall, the designed hierarchical diamond lattices demonstrated superior specific energy absorption of 2.62J/g and remarkable damage tolerance compared to state-of-the-art lattices. This study aims to provide new insights into the design of hierarchically structured cellular materials.