Mechanical properties of a novel hierarchical cellular structure architectured with minimal surfaces and Voronoi-tessellation

Abstract

Hierarchical structures are commonly found in nature due to their combination of low density, exceptional specific properties, and multifunctionality. Inspired by this, we proposed a novel hierarchical cellular structure based on triply periodic minimal surface (TPMS) by connecting two topologically identical and parallel sheets with a series of connecting ribs. A conformal design guideline was provided by describing the mathematical principles behind the generation of such hierarchical cellular structures. Then the designed structures with different configurations were fabricated via laser powder bed fusion (LPBF). Finally, the mechanical performance of the hierarchical cellular structures was analyzed by both experiment and numerical simulation. The dynamic compressive behavior was investigated using a Split Hopkinson pressure bar (SPHB) at a strain rate of 650 s−1, and the temperature distribution during tests was monitored using a high-speed infrared camera. As for quasi-static compression tests, it is found that the hierarchical cellular structure had good energy absorption characteristics and relatively low first peak stresses. These results showed that the structure could reduce strain rate hardening effects under dynamic loading, thereby mitigating the increase in first peak stress. The proposed hierarchical cellular structures showed good potential for efficient energy absorption under quasi-static and dynamic compression loadings.