Argianis’ graduate research focused on exploring natural material-based sandwich composites with enhanced noise mitigation. Cork turned out to be one of the most promising alternatives to traditional sandwich structures. His team compared sandwich structures made from a natural cork agglomerate core with those using a core made from a high-quality synthetic foam called Rohacell. Carbon-epoxy was used as the face sheet material with both cores.

“We achieved a 250 percent improvement in damping performance using the cork-based materials, with no sacrifice in mechanical properties,” Suhr says. “Also, cork radiates little to no noise and is inexpensive. It’s also sustainable and environmentally friendly because there are no carbon emissions associated with its production.”

Suhr sees the potential for application of cork-based sandwich structures in not only aircraft cabins but also car engine mounts, launch vehicle fairings and wind turbine blades.
In the next phase of the project, the team will investigate the low-velocity impact of these materials, he says.

The Drive Toward Soy-Based Foam

soybeanDeborah Mielewski, chemical engineer and technical leader of the plastics research group at Ford Motor Company, is responsible for developing the next generation of sustainable automotive materials. She is credited with developing the first soy-based foam.

“Even though we’re focused on bio products, lightweighting is a critical issue facing the auto industry,” she says. “We’re going to see the replacement of steel components with plastic components, and it will likely be with carbon fiber reinforcements to make high-end composite materials. My focus for natural fibers is to replace current plastic fibers that are weaker than glass fiber. There is an even bigger demand right now across the industry for high-performance plastic composites.”

Mielewski says Ford faced technical challenges associated with the soy-based foam project, including a funny odor and shape on the first day of testing, but the company launched the foam in the seat cushions of a new Mustang and received great publicity. Since then, she says, “We’ve witnessed an amazing migration of bio-technology into automotive production. Now, approximately 75 percent of all Ford vehicle headrests have soy in them. Seat cushions typically use a 12 percent soy content minimum and the head rest uses 25 percent. Now we’re focused on creating a biodegradable product that uses biomaterials. The soy-based foam cannot biodegrade, so it still goes to landfills like the petroleum foam it just replaced.”