Optimization of a lattice structure inspired by glass sponge.

The biomimetic design of engineering structures is based on biological structures with excellent mechanical properties, which are the result of billions of years of evolution. However, current biomimetic structures, such as ordered lattice materials, are still inferior to many biomaterials in terms of structural complexity and mechanical properties. For example, the structure ofEuplectella aspergillum, a type of deep-sea glass sponge, is an eye-catching source of inspiration for biomimetic design, many researches have introduced similar architecture in cellular solids. However, guided by scientific theory, how to surpass the mechanical properties ofE. aspergillumremains an unsolved problem. We proposed the lattice structure which firstly surpass theE. aspergillummechanically. The lattice structure of the skeleton ofE. aspergillumconsists of vertically, horizontally, and diagonally oriented struts, which provide superior strength and flexural resistance compared with the conventional square lattice structure. Herein, the structure ofE. aspergillumwas investigated in detail, and by using the theory of elasticity, a lattice structure inspired by the biomimetic structure was proposed. The mechanical properties of the sponge-inspired lattice structure surpassed the sponge structure under a variety of loading conditions, and the excellent performance of this configuration was verified experimentally. The proposed lattice structure can greatly improve the mechanical properties of engineering structures, and it improves strength without much redundancy of material. This study achieved the first surpassing of the mechanical properties of an existing sponge-mimicking design. This design can be applied to lattice structures, truss systems, and metamaterial cells.

Study on functional mechanical performance of array structures inspired by cuttlebone.

The cuttlebone structure is a complex porous bionic structure with an asymmetric S-shaped wall structure connecting laminar septa. Studies have shown that the cuttlebone structure has a low weight, high strength, and excellent energy absorption capability. To establish bio-inspired structures with superior biological functions, researchers have proposed the sinusoidally corrugated cuttlebone-like array structure (SCS). In this study, referring to Euler's theory combined with the Gaussian curvature, the effects of the thickness t, height H, amplitude A, and period P of the SCS under compressive shearing were analyzed. Through finite element calculations and parameter sensitivity analysis, the optimized Su4-Sl2 SCS was obtained. Based on the optimization results, a structure named the elliptical corrugated cuttlebone-like array structure (ECS) was designed. Various ECSs were prepared via three-dimensional (3D) printing, and the compression and shear deformation characteristics of the ECSs were analyzed through experiments and simulations. The results showed that the bearing capacities of the new ECSs were improved compared with those of SCSs; moreover, Eu60-El90, Eu60-El60, and Eu60-El60 ECSs had the best compressive and shear capacities. From the perspective of the stress, the peak compression, peak shear stress in the y-direction, and peak shear stress in the x-direction were increased by 14.2%, 32.8%, and 14.9%, respectively. From the perspective of the energy, the compressive strain energy, shear strain energy in the y-direction, and shear strain energy in the x-direction were increased by 22.8%, 33.0%, and 78.1%, respectively.