3D printed bike helmet can contract and deform, protecting riders’ heads

By Georgina Torbet Published March 26, 2025

A new bicycle helmet with a geometric design could help keep riders safer by reducing head injuries. Developed by researchers at the Universities of Gothenburg and Isfahan, the 3D printed helmet can better absorb shocks than traditional foam-lined helmets by deforming its shape as required.

Similar to the principle of crumple zones on a car, the idea is for the inner layer of the helmet to contract and absorb energy, so less force goes to a rider’s head during a collision.

“When exposed to energy from an impact, the liner material contracts, and this improves the absorption of impact energy, which means lower risks of injuries to a cyclist’s head in an accident,” explains lead researcher Mohsen Mirkhalaf of the University of Gothenburg. “We used a specific design optimization method to identify the best possible geometric configuration to minimize crash forces. The geometry of the material structure is a key factor.”

The geometry of the helmet was figured out using computer simulations, and then printed using 3D printing. The printed version used a material called a hyperelastic polymer, which can stretch, contract, and deform and then return to its original shape. The team tested out the printed version against traditional foam helmets in two types of crash scenario and found the new version protected the head better.

As well as offering better protection, the 3D printed helmet is also lighter, and its shape can be customized to the head of an individual rider. The researchers suggest it could be useful for professional athletes, or those who find curently available bike helmets uncomfortable, though the technology for printing the helmet means it is currently more expensive than traditional models.

“With further development, this technology could lead to a new generation of bicycle helmets that are safer, more comfortable and more customizable,” said Mirkhalaf. “Although 3D printing technology currently is more expensive than mass-produced foam liners, costs are expected to fall as the technology becomes more widely used. In the future, it may even be possible to have personalized helmets printed on demand, ensuring that each rider receives the best possible protection.”

The research is published in the International Journal of Solids and Structures.