Arshad Kudrolli, PhD, a professor of physics at Clark University, is working with Harvard University colleague Chris Rycroft, PhD, an assistant professor of applied mathematics, to determine what kinds of granular materials will make a prosthetic limb most comfortable for wear. The research team is investigating whether “dynamically jammed” materials, which are not of uniform shape and size and therefore fit together at odd angles, supply more durability as they are locked together under pressure. The researchers hope their experiments will lead to the creation of a more comfortable pad that fits between a person’s residual limb and the prosthesis.
Photograph of Kudrolli courtesy of Clark University.
“If the material is jammed better, then you can put more stress on it, and it will hold its shape for a longer period of time,” said Kudrolli
He noted that making a pad for a prosthetic limb is similar to creating a gel insert for a shoe. Basically, the chamber of the pad is filled with material and then all the air is evacuated. The remaining material offers support, cushioning, stability, and comfort. However, the very softness of a gel that makes a sneaker insert feel so welcome can actually give a prosthetic pad a looser, and therefore less stable, fit. Kudrolli and his team are experimenting with the perfect placement of other filler materials, which are often unpredictable when they are packed together. “On one hand you can have rougher shapes, and they can lock and have strength,” he says. “On the other hand, angular particles may not pack as well.”
The team is now seeking funding for the next round of research. “Clearly, there is a lot to be learned, but this has many potential applications,” he said. “This isn’t as direct as saving someone’s life, but what we do has a wide impact.”
Editor’s note: This story was adapted from materials written by Julia Quinn-Szcesuil, courtesy of Clark University.