Rigid materials cannot absorb shocks and cushioning materials are soft. Or are they? Researchers in Amsterdam have developed a material that combines both properties.
Materials are usually either rigid or damping. Rigid materials cannot absorb shocks or vibrations, while damping materials can. Researchers at the University of Amsterdam have developed a metamaterial that combines both properties: a lightweight steel structure that absorbs vibrations. They have published their results in Advanced Materials.
The trick was to use materials that buckle, such as thin sheets of metal. ‘A structure that buckles is very stiff before it bends, but it can absorb a lot of energy during bending,’ says co-author Corentin Coulais. ‘Our structure can absorb 100 times more energy than ordinary steel.’ According to Coulais, their method can work for any material in principle, but in practice you need a material that can withstand strain without fatigue or plastic deformation, such as stainless steel.
‘Building the metamaterial out of metal was the trickiest part,’ says Coulais. To test their creation, they attached it to an electromechanical shaker and placed a mass on top of it. Using two accelerometers, one at the bottom and one at the top of the structure, and a high-speed camera at the front, they were able to show that their material was both stiff and capable of absorbing vibrations. The researchers expect their metamaterial to have many applications, for example in automotive and aerospace engineering.
Dykstra et al. (2023) Adv. Mat. https://doi.org/10.1002/adma.202301747 (Open Access)