A rhombic bidirectional re-entrant honeycomb with enhanced dual-platform stress characteristics and programmable mechanical properties

To improve the carrying and energy absorption, honeycombs with multi-platform stress characteristics have attracted further attention. In this study, two rhombic bidirectional re-entrant honeycombs (RBRHs) are designed by adding rhombic parts to the bidirectional re-entrant honeycomb (BRH), namely RBRH-A and RBRH-B. The compression responses of RBRHs are studied through quasi-static compression experiments and finite element (FE) simulations. Experiments and FE simulations have shown that RBRHs exhibit dual-platform stress characteristics on their stress-strain curves. Parameter analyses are conducted to further discuss the influence of geometric parameters on the dual-platform stress characteristics. The results indicate that wall thickness can affect the value of platform stress, and inclined angle can affect whether RBRHs exhibit dual-platform stress characteristics. In addition, programmable design is carried out for RBRHs, enabling programming of the values of two platform stresses and the range of the first platform stress stage. Compared with RBH, the adding of rhombic parts enhances the dual-platform stress characteristics and SEA. The SEA of RBRH-A is 72 % higher than BRH, and RBRH-B is 160 % higher than BRH. These studies help to broaden the scope of research on the multistage energy-absorbing performance of honeycomb materials and promote their application in lightweight body parts, energy-absorbing panels, elastomeric structural components, and smart sensors. • Two types of rhombic enhanced bidirectional re-entrant honeycomb are designed by adding rhombic parts. • Parameter analyses are given to discuss the influence of geometric parameters on the dual-platform stress characteristics. • The adding of rhombic parts enhances the dual-platform stress characteristics and SEA.