The disappearance of Malaysian Airlines Flight 370 brought to light the need for a change in aviation communications. Some researchers have focused on the potential for 5G in breaking the sonar/radio wave communication barrier to provide enhanced tracking of flights and recovery when the worst happens.
Others are looking at the planes themselves. What if before a plane went down, the aircraft itself could monitor and communicate its structural integrity? Scientists at the Department of Energy’s Oak Ridge National Laboratory (ORNL) are developing “smart” carbon fiber composites to do just that.
As structural materials used in the aerospace and automotive industries, carbon fiber composites have proven their worth. They are lightweight yet strong, but they do have a weakness. They include a polymer mix, like epoxy, which is embedded to reinforce the fibers. The property differences between the materials can result in the fibers detaching. Unfortunately, such changes are often undetectable.
“Carbon fiber composites fail catastrophically, so you won’t see damage until the entire structure has failed,” said Chris Bowland, a Wigner Fellow at ORNL. “By knowing what’s going on within the composite, you can better judge its health and know if there is damage that needs to be repaired.”
The ORNL team’s solution was to develop semiconducting silicon carbide nanoparticles that can be applied via a roll-to-roll process onto electrically conductive carbon fibers. In addition to being stronger than other composites, the nanomaterial-embedded one can monitor its own structural health.
According to the team’s research, “When enough coated fiber is embedded in a polymer, the fibers create an electrical network and the bulk composite becomes electrically conductive. The semiconducting nanoparticles can disrupt this electrical conductivity in response to applied forces, adding an electromechanical functionality to the composite.”
Any strain on the composite, such as turbulence, affects the connectivity of the coated fibers and results in an electrical resistance, which could serve as a warning or signal that an inspection is needed.
In addition to the composites’ ability to indicate trouble, the researchers also looked at energy dissipation. They measured the vibration-damping behavior of composites embedded with different amounts of nanoparticles. Every amount resulted in enhancing energy dissipation ranging anywhere from 65 to 257 percent. That means these coated carbon fibers could be structurally stronger to deal with impacts, shakes and other stresses.
ORNL’s process has the potential to greatly impact the automotive, aerospace, transportation and energy industries. The scalability of the process could mean producing renewable and low-cost carbon fibers in other industries as well.
Interested in more aerospace innovations and the direction it is headed? Check out Spike Aviation to Produce Supersonic Passenger Jet by 2023 and Boeing Outlines Vision for Future of Aerospace.