Oliver Myers (right) and mechanical engineering master’s student Brandon Williams work with some of the smart material they are developing at Clemson University. Image credit: Clemson University RelationsImagine if your car could react to incurring damage the way a person reacts to a stubbed toe or a twisted ankle. While not sensing pain, vehicles may someday be able to transmit information to a computer, similar to how nerves tell the body it has been injured.

Researchers at Clemson University, with funding from the U.S. Army Research Laboratory, are working to make this a reality. The idea is that magnetically sensitive material would be embedded within "smart material" throughout the vehicle and act as a sensor that says, “Ouch! We have damage here,” said Oliver Myers, an associate professor of mechanical engineering.

Just as pain is relayed to the brain, the damage report would go to a computer and help determine whether a vehicle should keep going or return to the depot.

The research could help the Army save money on rotorcraft maintenance, said Asha Hall, the lead co-principal investigator and prognostics and diagnostics acting team lead in the mechanics division of the Vehicle Technology Directorate at the U.S. Army Research Laboratory.

As a safety measure, the Army replaces some parts based on how long they have been in service, whether they appear damaged or not. Embedded sensors could make it possible for parts to remain in service longer, based on their condition, Hall said.

“We’re trying to extend that maintenance-free operating period,” she said. “The big, big impact is to reduce sustainment costs for the Army.”

The research builds on the fast-growing field of composite materials, which are used in a variety of products from cars to airplanes. Composite materials often look and feel like plastic but are lighter and stronger than metals, including steel.

By sandwiching “magnetostrictive” material between multiple layers of composite materials, the team is creating a laminate. The magnetostrictive material responds to a magnetic field or a change in stress, allowing it to act as the nerve that senses the damage.

“The composite laminate effectively becomes a smart structure,” Myers said.

The types of damage it could detect include impacts, cracking and unusual loading, he said.

Part of what makes the team’s approach unique is that the magnetostrictive material that senses the damage is embedded in the structure itself during the fabrication process, rather than attaching sensors after the structure is already built.

Those external sensors often require additional equipment, Myers said. The magnetostrictive material his team is developing requires no power, is lightweight and operates in harsh environments.

The central question Myers is asking is how the team can create a “robust sensing operation” using the embedded magnetostrictive material. Robust would mean it is observable, repeatable, measurable and sustainable.

“We want this to not only be a benchtop experiment, but we want to be able to put it on larger structures and larger systems so that once we go from the benchtop coupon level we go to a full-size system and have it function as an NDE, or nondestructive evaluation, structural health-monitoring platform,” he said.

Deployment to the field could be 10-20 years away, but Myers aims to move the research in that direction.