Tests conducted on composite aircraft fuselage test panels show that new sensing technology from Luna Innovations Incorporated (NASDAQ: LUNA) offers aerospace manufacturers and operators greater insight into the condition of composite structures.
Highly distributed strain sensing is now available with Luna’s ODiSI (Optical Distributed Sensor Interrogator) instrument. According to tests conducted by the University of California-San Diego and the FAA Airworthiness Assurance Center operated by Sandia National Labs, the ODiSI measures the performance, tolerances and failure mechanisms of structures and vehicles.
Researchers fired ice balls of approximately 2.5 inches in diameter onto two carbon fiber-epoxy test panels representative of composite surfaces found on a range of modern aircraft such as the B787, A350 or A380. In one panel optical sensing fiber was embedded within the composite laminate during layup and co-cured; in the second panel sensing fiber was surface bonded to the panel skin.
Results showed residual, lasting strain after the impact, offering better insight into how the impact of debris and collisions affects composites. Looking at the residual strain in the fiber as it is mapped to the panel surface, the impact location is identifiable in a single scan of the laser by the strain left in the fiber. Current inspection techniques are labor intensive and require examination of the surface in small sections at a time.
“Our technology gives manufacturers and operators the ability to know what is happening inside composite structures and see damage even if it’s not visible,” said My Chung, CEO. “The tests demonstrate that composite structure testing is not only possible but that manufacturers and operators can test the condition of composite structures like never before.”
ODiSI provides a constant picture of a structure’s load distribution with a sensor mass of only a few grams. It utilizes low-cost optical fiber for unprecedented sensor density for strain or temperature sensing applications and delivers hundreds of measurement locations per meter of fiber with resolutions of a few microstrains.