Kranium is made of ribs of corrugated cardboard that are slotted together into an array. Under impact the ribs can flex to absorb energy and under extreme loading the cardboard will crumple. When tested at Imperial College against the British Standards (EN 1078) it performed 4 times better than standard expanded polystyrene helmets. Kranium was the subject of Anirudha Surabhi’s masters in Innovation Design engineering at the Royal College of Art.
Website link: Kranium: effective cycling protection