Researchers at Johns Hopkins University have developed a new shock-absorbing material that’s super lightweight, while still providing the protection of metal. These elements could create lighter, stronger and, above all, reusable helmets, armor and vehicle parts.
The key to the new material is something called liquid crystal elastomers (LCE). They are networks of elastic polymers in a liquid crystalline phase that give them a useful combination of elasticity and stability. LCEs are normally used to make actuators and artificial muscles for robotics, but for the new study, the researchers investigated the material’s ability to absorb energy.
The team created materials consisting of angled LCE beams sandwiched between rigid support structures. This basic unit has been repeated on the material in multiple layers, so that they deform at different speeds upon impact, effectively dissipating energy.
In a series of experiments, the team tested the material’s ability to withstand impacts from different masses at different speeds. The materials were struck by objects weighing between 4 and 15 lbs (1.8 and 6.8 kg) at speeds of up to 22 mph (35.4 km/h) and, sure enough, they held the blow.
Perhaps unsurprisingly, the material performed better with more layers of cells. A four-layered structure, for example, had almost twice the energy absorption density of a single-layered structure.
While the materials have so far only been tested with impacts of up to 22 mph, the team says they should also be able to absorb impacts at higher speeds.
Researchers say the material could be used to improve the safety of helmets, body armor, car bumpers and other vehicle and aircraft parts, effectively dissipating impact energy while remaining light.
“We are thrilled with our findings on the new material’s extreme energy absorption capability,” said lead author Sung Hoon Kang, assistant professor of mechanical engineering. “The material offers more protection against a wide range of impacts, but being lighter could reduce fuel consumption and the environmental impact of vehicles while being more comfortable for wearers of protective gear.”
The first use case will be helmets, as the team is currently working with a company to design and test this type of protective gear for athletes and the military.
The research was published in the journal Advanced materials.
Source: Johns Hopkins University