Bio-inspired Structures for Enhancing Energy Dissipation of Helmets

The risk of concussion remains high in snow sports, even with a high helmet adoption rate. Novel helmet designs with enhanced energy dissipation are needed to solve this issue. In this study, helmet liners with bio-inspired honeycomb structures were proposed and fabricated with SLA 3D printing technology. The structures exhibited a distinct progressive folding behavior in the out-of-plane crushing tests. The buckling and plateau stress of bio-inspired honeycombs are higher than that of traditional ones. FEM models were developed in Abaqus to simulate the progressive folding behavior. The stress and strain curves obtained from the simulations match the test data to a great extent. Based on the simulations, the bio-inspired honeycombs can absorb the same amount of energy with a 24% weight reduction compared to EPS foams. Improvement is possible with smaller unit cells at the same equivalent density. Different material properties can influence the bucking and plateau stress of the structures differently. And with a multi-layer design, the honeycomb liners have the potential to suit a wide range of impact energy.