Meta-honeycomb sandwich tubes: Designing, manufacturing, and crashworthiness performance

Sandwich tubes with meta-honeycomb core of zero Poisson's ratio were designed and fabricated. The meta-honeycomb can realize free curl deformation of cylindrical surface, which is beneficial to manufacture cylindrical sandwich shells with large curvature. For the hexagonal honeycomb structure, forcing the honeycomb panel to roll can lead to localized fragmentation of the honeycomb. However, if the Poisson's ratio is negative by changing the cell shape, then it can allow the structure to achieve greater centripetal curvature. Lateral and axial compression tests were carried out to investigate the crushing behaviors of these composite honeycomb sandwich tubes (CHSTs). The CHST has stable crushing curve and crushing pattern, just like thin-walled aluminum tubes. With higher peak force, plateau force, and specific energy absorption, the CHST is more stable and efficient in energy absorption than thin-walled composite tubes.