4D printed bio-inspired polygonal metamaterials with tunable mechanical properties

Conventional vibration isolators are designed and assembled so that their structure and vibration isolation performance cannot be adjusted and have a single function when facing complex working conditions. Inspired by a cat's adaptive adjustment of its limb structure to land safely when leaping from a height, we designed a bio-inspired polygonal metamaterial and 3D-molded it based on 4D printing of shape memory polymers (SMP). Based on the shape memory effect of the SMP, the BPM can obtain arbitrary temporary shapes under the combined effect of temperature and force. According to the analysis of the energy absorption test, by change the compressive strain of the BPM temporary shape, it is possible to adjust the shape of the single-cell structure while decreasing its specific energy absorption by up to 80 %. The locally controllable compressive deformation and programmable mechanical properties of the BPM structure are achieved through rational structural parameter design. In addition, thermally tunable vibration-absorbing behavior is achieved by combining the tunable stiffness properties of the printed material. This study provides new possibilities for intelligent tuning of cushion vibration isolators under complex and variable operating conditions.