Predicting and preventing component failures before they occur is a key theme of modern aircraft and engine maintenance, but many parts of an aircraft remain isolated from health monitoring systems.
Carbon fiber, for instance, increasingly is being used on modern airframes, but there is often no way to detect cracks before they occur using non-contact methods such as acoustic and ultrasonic inspections. Those methods can spot flaws, but they don’t provide any information about stresses that build up in parts from operational loads such as vibratation, temperature and impact.
Stresses can be assessed using adhesive film sensors, as examined by research conducted by the FAA more than a decade ago.
In those tests, resonance sensors were glued to composite panels to assess damage progression after a flaw was introduced.
Now, new research is pointing to a better, non-contact method using circuits embedded in composite materials.
Scientists led by Professor Sergey Kaloshkin from the NUST MISIS Center of Composite Materials have proposed using soft magnetic circuits only 10-60 microns in diameter to measure stresses in carbon fiber, which would have the micro-wires laid in a grid between plies.
Stress near the micro-wire affects how the substance reacts to external magnetic fields, and from there one imagines the next step would be a system to relay such reports to an aircraft’s health monitoring system.
The scientists, who say they can embed the wires without affecting the structural properties of the material, are seeking to develop a field prototype.
The NUST MISIS research was originally published in the Journal of Alloys and Composites.