Smart Skins sensors are ready for takeoff

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Giovanni Nino, Quest Integrated LLC

Novel sensors are 3D printed into the ‘skin’ of an airplane wing and used to monitor aircraft loads and structural responses during flight.

A new technology that uses 3D printing to embed flight sensors on an aircraft wing could allow for manufacturing stronger, safer planes.

Currently, sensors used to detect such things as airflow over the wings and pressure, are manufactured then adhered atop the aircraft wing. But this new technology allows for embedding sensors within the wing itself, enabling more precise measurements of stress or pressure that could disable an airplane or unmanned aircraft.

“This enables us to integrate sensors in a way that has not been done before, because you can put these sensors directly on a wing surface,” said David Borkholder, the Bausch & Lomb Professor in the microsystems engineering department in RIT’s Kate Gleason College of Engineering.

The project is part of the Air Force Small Business Technology Transfer Initiative. Working with sponsors Quest Integrated and the U.S. Air Force Research Laboratory scientists, Borkholder is part of the team helping to develop a new sensor system called Smart Skins. These are ultrathin, printed electronic devices of 50 microns—the equivalent of a human hair—but strong enough to detect information about the effect of airflow across the wing and how this pressure might change material properties and structural reliability.

Direct write-creation of sensors on plane wings had not been done previously, and using advanced manufacturing equipment and new nano-inks helped the project take flight. At RIT, College of Science faculty-researcher Scott Williams developed the nano-powder ink used to print the new sensors onto scale wing structures made of aluminum. Borkholder 3D-printed the electronics with Denis Cormier, director of RIT’s AMPrint Center, using the laboratory’s high tech ink jet deposition systems, as well as its state-of-the-art photonic systems that process metal and ceramic inks for applications such as novel sensors. The electronic devices can be printed onto different composite materials without damage from the sintering procedure, even using the high heat of the photonic systems.

“We developed technologies that allow us to use piezoelectric materials that could measure either strain or pressure on the wing. It allows us to produce those materials on any type of substrate,” Borkholder said. Piezoelectricity is an electrical charge separation produced within materials when subjected to mechanical stress or pressure. Alternately, applying a voltage across piezoelectric materials can cause them to change shape.

Previously, commercial sensors were affixed to aircraft wings using adherents or miniature fasteners. Both interfered with measurements. This integration of printed electronics and 3D printing processes could accelerate design, fabrication and testing of smart systems anywhere on an aircraft structure, Borkholder said.

“As Quest and the Air Force are developing new aircraft, whether with new materials or new structures, they need to understand how those materials and structures perform,” Borkholder said. “And the direct printing and low temperature sintering technologies allow us to understand that on any substrate material—even paper.”