The rotorcraft concept represents reactive reinforcements that, when exposed to ultraviolet light, will increase the mechanical behavior on-demand. (U.S. Army illustration)

Engineers developed a technique that causes a composite material to become stiffer and stronger on-demand when exposed to ultraviolet light. This on-demand control of composite behavior could enable a variety of new capabilities for future Army rotorcraft design, performance, and maintenance.

The composite materials could become 93% stiffer and 35% stronger after a five-minute exposure to ultraviolet light. Future structures based on this work may lead to new composites with controlled structural damping and low weight that could enable high-speed rotorcraft concepts that are currently not feasible.