Real-Time Damage Detection in an Airplane Wing During Wind Tunnel Testing Under Realistic Flight Conditions

A real-time structural health monitoring (SHM) system of an airplane composite wing with adjustable damage is reported, where testing under realistic flight conditions is carried out in the controllable and repeatable environment of an industrial wind tunnel. An FBG-based sensing array monitors a debonded region, whose compromised structural strength is regained by a set of lockable fasteners. Damage tunability is achieved by loosening some of or all these fasteners. Real-time analysis of the data collected involves Principal Component Analysis, followed by Hotelling's <i>T</i>-squared and <i>Q</i> measures. With previously set criteria, real-time data collection and processing software can declare the structural health status as normal or abnormal. During testing, the system using the <i>Q</i> measure successfully identified the initiation of the damage and its extent, while the <i>T</i>-squared one returned limited outcomes.