Crushing behavior and energy absorption of the thousands-of-eyes-Bodhi-inspired novel hierarchical cellular structure

Natural hierarchical materials are proved to have excellent mechanical properties and have been widely applied in the design concept of engineering materials. In this study, inspired by the hierarchical structure of the thousands-of-eyes-Bodhi (TEB), a novel biomimetic hierarchical cellular structure is designed and fabricated using 3D printing technology. The crushing resistance capability and deformation mode of TEB-inspired hier-archical cellular structure are investigated by experiments and simulation methods. Meanwhile the deformation processes are recorded by the compression experiments, and the strain field distributions are analyzed by the digital image correlation (DIC) method. Comparing the mechanical behaviors of square tube, second-order and TEB-inspired hierarchical cellular structures, it is found that the structure hierarchy affects the deformation mode, improves the strain field distribution, delays the strain concentration, and enhances the crashworthiness. It is also noted that the TEB-inspired hierarchical cellular structure exhibits different deformation modes and strain field distributions in the transverse and longitudinal directions, and shows better crushing resistance in the longitudinal direction. In addition, compared with other typical natural materials and engineering materials, the TEB-inspired hierarchical cellular structure possesses superior specific energy absorption and specific strength. These findings provide a new perspective for the application of biomimetic engineering materials.