Title: EXTRACTING INFORMATION FROM DAMAGED CARBON FIBER COMPOSITES USING HIGH DEFINITION FIBER OPTIC SENSING (HD-FOS)
Abstract: In contemporary helicopters, rotors are fabricated from composite materials due to an advantageous strength to weight ratio and relatively graceful failure mechanisms. Despite this, there were 127 accidents involving U.S. registered rotorcraft in 2011, 23% of which were the result of a system component failure. One reason for this is that an effective method of nonvisual damage detection for composite aerospace components post-flight remains a challenge. Moving toward a solution to this problem, Luna has incorporated high spatial resolution (1.25 mm) fiber optic strain sensors into multiple carbon fiber composite test articles representative of those that make up the structure of a standard rotor blade. These articles were used to demonstrate the ability to detect and assess the onset of damage from impacts as well as high cycle fatigue, similar to what might be encountered during flight. Multiple test articles and testing schemes were implemented during the experimentation phase of this work. The first test was of a statically loaded commercial tail rotor blade to demonstrate the capabilities of high definition fiber optic sensing (HD-FOS). The next test was a high cycle fatigue (HCF) test to capture in-situ measurements of the fatigue behavior of a CFRP beam. The next tests consisted of a beam and mock skin panel subjected to a series of impact events. By providing a mechanism for measuring and tracking the condition of a rotor, lifetime and maintenance can be simultaneously optimized for maximum safety and minimized cost.
Authors: Dan Kominsky, Nur Aida Abdul Rahim, Matthew A. Davis, Naman Garg, Matt A. Castellucci, Reginald L. Bryson, Noah B. Beaty
Conference: CAMX 2017 –Orlando