Adaptive Materials Bring Futuristic Aircraft Closer to Reality
Jeffrey Heimgartner posted on April 20, 2018 |
U.S. Army research engineers develop materials that adjust and strengthen when exposed to ultraviole...

An industrial-era mindset toward procuring military equipment served the United States well for decades—invest in equipment built to last 40 or 50 years over, and over and over that rarely changes. Taking a cue from the technology sector, the U.S. Army has plans to modernize with a push toward a fleet of Future Vertical Lift (FVL) aircraft. Like software, phones and other devices, this fleet would be built for change as new capabilities are developed.

Although a fleet of FVLs is still off in the distance, researchers with the U.S. Army Research Laboratory and University of Maryland have shortened that time frame. The team discovered a technique that makes a composite material become stiffer and stronger when it’s exposed to ultraviolet light. This on-demand control of a composite’s behavior has the potential to significantly impact aircraft design, performance and maintenance.

“An important motivation for this work is the desire to engineer new structures, starting from the nanoscale, to enable advanced rotorcraft concepts that have been proposed in the past, but were infeasible due to limitations in current composites,” said Bryan Glaz, chief scientist of ARL’s Vehicle Technology Directorate. “The enhanced mechanical properties with potentially low-weight penalties, enabled by the new technique, could lead to nanocomposite-based structures that would enable rotorcraft concepts that we cannot build today.” 

Army researchers imagine a rotorcraft concept that when exposed to ultraviolet light will increase the mechanical behavior on demand. According to the researchers, control of mechanical behavior could potentially lead to increased aerodynamic stability in rotorcraft structures. (Image courtesy of U.S. Army Research Laboratory.)
Army researchers imagine a rotorcraft concept that when exposed to ultraviolet light will increase the mechanical behavior on demand. According to the researchers, control of mechanical behavior could potentially lead to increased aerodynamic stability in rotorcraft structures. (Image courtesy of U.S. Army Research Laboratory.)

The research focused on controlling molecule interaction. According to Frank Gardea, a research engineer, the goal was to “have them interact in such a way that changes at a small size, or nanoscale, could lead to observed changes at a larger size, or macroscale.” The team achieved the results it wanted and demonstrated that these composite materials could become 93 percent stiffer and 35 percent stronger after five minutes of exposure to ultraviolet light.

The technique involves attaching ultraviolet light reactive molecules to reinforcing agents, like carbon nanotubes, which are then embedded in a polymer. Ultraviolet light exposure creates a chemical reaction that increases the interaction between the reinforcing agents and polymer, thus making the material stiffer and stronger.

Although military aircraft were the driving force behind the research, the work has the potential for multiple uses. The chemistry used in the technique could be applicable to various reinforcement/polymer combinations, opening up this method to applications with various materials.

Interested in more ways technology could help bring the military into the future? Check out Squids and the Future of Military Tech and Elastomeric Military Vehicle Frame Guards Against Brain Trauma

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