Design principles for dual-phase lattice cylindrical tubes with excellent energy absorption capability

To further increase specific energy absorption capacity of lattice materials, this study proposed dual-phase lattice cylindrical tubes (DPLCTs) that emulated the sinusoidal-helicoidal architecture of the peacock mantis shrimp. The metamaterial composites were printed from austenitic stainless steel using additive manufacturing and compressed. Quasi-static axial compression tests revealed that DPLCTs exhibited higher specific energy absorption (SEA) than the corresponding single-phase lattice cylindrical tubes (SPLCTs). Those with the largest amplitude-to-width ratio, exhibited superior specific energy absorption, respectively 74 % and 14 % greater than that of matrix phase (MP) and reinforcement phase (RP) based SPLCTs. After the incorporation of the second phase, more complex deformation modes were observed associated with truss plastic buckling or twisting, RP grain rotation or connected RP grains moving along the phase boundary. In addition to the previously reported interaction deformation mechanism of "phase boundary slip", "reinforcement phase rotation" was observed as another deformation mechanism, which could improve the energy absorption capability by postponing densification strain. Together with computational analysis, the interaction deformation mechanism was found to vary depending on amplitude-to-width ratio (gamma). Finally, design principles for lattice cylindrical tubes with greater energy absorption capability were summarized. The study will provide further guidance for the development of impact-resistant engineering structures.