Charged Up Materials

Project: Multifunctional materials for electromagnetic applications
School: University of Delaware
Location: Newark, Dela.
Directors: Dr. Shridhar Yarlagadda and Dr. Mark Mirotznik


Mark Mirotznik and Shridhar Yarlagadda use the computerized loom at the Composites Manufacturing Science Laboratory at the University of Delaware.

Lots of hybrid fabric research has focused on increasing toughness and durability. But researchers from the University of Delaware (UD) Center for Composite Materials are evaluating composite materials in hybrid fabrics for electromagnetic (EM) applications.

The military is interested in how EM waves propagate through custom textiles and controlling EM behaviors when joining them with structural components. But there is also commercial interest. Research into EM materials could lead to “ships of the future” with antennas integrated directly into their load-carrying structures or enclosures for aircraft or cell phone towers that protect against lightning strikes or allow electronic signals to pass through them.

Shridhar Yarlagadda, assistant director of research at UD’s Center for Composite Materials and project director, explains that the team working on this U.S. Navy-funded project plans to create custom layers of two-dimensional fabrics and evaluate EM properties of fabrics.

The researchers answer the basic question of “what to make” by creating analysis software and other design tools that can predict performance. The group is currently in the design stage. It has built models to predict properties of fabric architectures and validated them using carbon fiberglass.

The team is now checking if the models still work when they add other fibers for hybrids. They hope to eventually model all types of fibers, but are developing the model using two major fibers – carbon and polyethylene.

 The team at UD is also performing basic research to understand what kind of wave propagation they can design into a material, how to tailor EM properties in a structure and what level of tailoring they can accomplish. Of mechanical interest are the fabric’s stiffness, strength, weight and durability.

On the electromagnetic front, the group focuses on dielectric properties and conductivity at multiple scales, depending on the architecture of the devices created. They look at hardness patterns, changing the ordering of the fibers and mixing carbon and glass in different directions and in different ratios.

 “Not only is understanding what is happening at the fiber level important, but as EM waves propagate in a material, the size and geometries of what they travel through – and how the fibers are arranged – also matter at most frequencies,” says Yarlagadda. “We are creating interesting architectures of dielectric and conductive fibers to observe what EM behaviors we can control.”

If all goes as planned during the design phase, the team at UD will build the hybrid fabrics and test them later this year, weaving architectures in 2D on a small-scale industry standard prototyping loom, purchased through a grant from the Office of Naval Research. The automated and computer-controlled loom allows users to mix and hybridize fabrics and create custom stacks.

With the tools developed in this project, Yarlagadda is confident the team will be able to design useful multifunctional structures. “The loom allows us to make a broad array of custom composite fabrics,” says Yarlagadda. “Just about anything we can design, we can make with this piece of equipment.”