| Popis: |
Impact attenuating materials fulfill an essential role in applications as diverse as protective packaging, shock isolators for electronics, vehicle interiors, and helmet padding. These materials are typically cellular in construction, and are designed to absorb impact energy through the collapse of pores within the material below a threshold force (or acceleration), thereby mitigating damage or injury. Polymer foams are the most common impact attenuating materials, and see widespread use in many industries. Recent advances in additive manufacturing techniques have enabled the fabrication of cellular materials with architected lattice topology. Here it is demonstrated that via design of cellular architecture the dynamic stress-strain response can be tailored, resulting in elastomeric lattices with impact attenuation performance significantly exceeding that of state-of-the-art foams for both single and multi-impact scenarios. Then, the additional degrees of freedom in the design of the cellular architecture of lattice based impact attenuators are leveraged to optimize their performance for a typical helmet impact scenario whereby the contact area increases during deformation. An improvement over state-of-the-art vinyl nitrile foam helmet pads is achieved during a standard helmet test leading to lower head acceleration. This breakthrough could pave the way to helmets with improved injury protection. |
