Novel helmet liner designs

Shear-thickening materials and lattice structures have potential to improve head protection against impacts. However, their design should be optimised to produce superior performance compared with traditional foam-based liners.

We explored whether digital elastomers can be used in cylindrical arrays with concave and convex shapes to allow for tuning the shear response and compressive response independently.

We first characterised elastomers made via additive manufacturing for large strain and high rate deformations. We then used them in finite element models of new helmet liners made of cylindrical arrays.

We found while it is possible to tune the shear response of the arrays as coupons, placing them in helmet liner poses new design challenges, including early bottoming out of the convex shape. This study provides guidelines for designing new helmet liners made of novel materials, showing that the difference between material response in coupons vs liners.