A new fabrication method for hierarchical truss materials with millimeter-scale struts

Hierarchical truss materials with millimeter-scale struts have been fabricated using a three-dimensional printing and interlocking method. The limitation designs of hierarchical truss materials have been found in this short letter to show the imperfection of hierarchical materials. The analytical models and experimental work have been conducted to investigate the restriction mechanism of the hierarchical design. Polymer hierarchical truss materials with low relative densities (0.66–2.67%) have been fabricated for compressive tests. Euler buckling of hierarchical and first order truss materials has been observed in our experiments. Our conclusions are very useful for accurate comprehension of hierarchical construction and designing ultra-lightweight hierarchical truss materials with high specific strength at low density to avoid the deficiencies of this structural configuration.