The importance of protection in football and bicycle helmets has become a hot topic as scientists learn more about brain injuries. Researchers from the University of Colorado of Boulder and Sandia National Laboratories designed padding capable of withstanding strong impacts that can be 3D printed on commercially available printers. 

“Impact mitigation is something that’s important everywhere,” said Robert MacCurdy, Assistant Professor at the Paul M. Rady Department of Mechanical Engineering at University of Colorado Boulder. “It’s in highway crash barriers, knee pads and elbow pads, and in packaging equipment.” 

Traditional foam padding, filled with tiny holes, is effective but can become rigid over time when pressed and squeezed. The research team, realizing this shortcoming of foam padding, worked on a computer algorithm to redesign the interior of padding material that could absorb force more effectively and efficiently than current materials. By designing a honeycomb of 3D printed thermoplastic polyurethane blocks, the researchers created padding that efficiently absorbs impact in a wave-like pattern instead of squeezing down like traditional foam. When tested, the newly developed padding proved to absorb up to 25% more force than traditional foam padding. 

“The material you use for absorbing impacts matters,” MacCurdy added. “But what really matters is the geometry.”