Protective material is lighter

A team of Johns Hopkins University researchers created shock-absorbing material that protects like a metal but is lighter, stronger and reusable. The new foam-like material could be a game-changer for helmets, body armor and automobile and aerospace parts.

“We are excited about our findings on the extreme energy absorption capability of the new material,” said senior author Sung Hoon Kang, assistant professor of mechanical engineering. “The material offers more protection from a wide range of impacts, but being lighter could reduce fuel consumption and the environmental impact of vehicles while being more comfortable for protective gear wearers.”

Kang, who is also a fellow at the Hopkins Extreme Materials Institute, wanted to create a material even more energy-absorbing than current car bumpers and helmet padding. He noticed that typical materials used for these critical protective devices don’t perform well at higher speeds and often aren’t reusable.

The research team increased the ability of the material to withstand impact by using high-energy-absorbing liquid crystal elastomers, which have been used mainly in actuators and robotics.

During experiments to test the capacity of the material to withstand impact, the substance held up against strikes from objects weighing about 1.8 kg to 6.8 kg (4 lbs. to 15 lbs.), coming at speeds of up to about 35 kph (22 mph). Tests were limited to 35 kph due to limits of the testing machines, but the team is confident that the padding could safely absorb even greater impacts.

Kang and his team are exploring a collaboration with a helmet company to design, fabricate and test next-generation helmets for athletes and the military.

The team also included Lichen Fang, former graduate student; Thao “Vicky” Nguyen, professor of mechanical engineering; Beijun Shen, graduate student; Seung-Yeol Jeon, former postdoctoral researcher at Hopkins Extreme Materials Institute; Zeyu Zhu, former graduate student; and Nicholas A. Traugutt and Christopher M. Yakacki, both of University of Colorado, Denver.

The research is supported partly by the Army Research Office (grant No. W911NF-17-1-0165) and the Johns Hopkins University Whiting School of Engineering Startup Fund. 

— Johns Hopkins University