| dc.description.abstract | Honeycombs excel at absorbing energy during quasi-static crushing events. Adding hierarchical structures to
these designs improves their effectiveness. Hierarchical structures are best built using additive manufacturing
technologies. There is, however, limited experimental data on their crush-resistance. This renders it difficult to
improve and validate current theoretical and numerical models on the deformation behaviour of hierarchical
honeycombs. This study aims to design vertex-based hierarchical honeycombs and examine their surface quality
and mechanical behaviour for quasi-static crushing scenarios. Zero-, first-, and second-order hierarchical honeycombs
were designed and fabricated using direct metal laser sintering technology. The Ti6Al4V specimens
were quasi-statically crushed using the MTS CriterionTM, Model 43 universal testing machine to evaluate the
deformation behaviour of honeycomb topologies with different levels of hierarchy. Surface roughness analysis
revealed that the average surface roughness (Ra) increased with the order of hierarchy, with lower Ra values on
top flat surfaces compared to side inclined surfaces. Mechanical testing showed deformation occurred primarily
through beam bending, with pronounced buckling under y-direction loading. The load drop after peak values
was attributed to fracture at the vertices of the walls. The sequential collapse of the hierarchical honeycombs
under compression began with the lowest order of hierarchy, involving bending, buckling, Poisson’s ratio lateral
expansion, and sliding along inclined and horizontal lines. Zero-order hierarchical honeycombs exhibited the
lowest failure loads, while second-order hierarchical honeycombs had the highest. The design-to-experiment test
approach was employed to predict the performance benefits of hierarchical honeycombs, providing valuable
insights and highlighting design limitations to address crash-worthy additively manufactured hierarchical lattice
structures. | en_US |
