Feasibility study on the use of a hierarchical lattice architecture for helmet liners

Helmets are the most important piece of protective equipment for motorcyclists. The liner of the helmet is
the main part of the helmet which dissipates the impact energy and mitigates the load transmitted to the
head. Therefore, optimizing the material that absorbs most of the impact energy would improve the helmet’s
protection capacity. It is known that the energy absorption of the helmet liner can be optimized by means of
using liners with varying properties through the thickness, however currently the majority of used liners
exhibit constant properties through the thickness. Advances in the field of topology optimization and additive
manufacturing provide the ability of building complex geometries and tailoring mechanical properties.
Along those lines, in the present work the feasibility of using a hierarchical lattice liner for helmets was
studied. Finite element method was employed to study whether a hierarchical lattice liner could reduce the
risk of head injuries in comparison to currently used liner materials. The results show that using a hierarchical
lattice liner has the potential of significantly reducing the risk of head injury compared to a helmet
with traditional EPS liner and could potentially be considered as the new generation of energy absorbing
liners for helmets.