Impact localization and force estimation on a composite wing using fiber bragg gratings sensors

Automated detection of damage due to low energy impacts in composite structures is very important for aerospace structural health monitoring (SHM) applications since it creates subsurface damage which can significantly reduce the stiffness of a component. Fiber Bragg grating (FBG) sensors are showing promise in many applications since they are low weight, require minimal space, are immune to electromagnetic interference, and can support multiple sensors in a single fiber. This paper proposes a novel methodology for impact localization and prediction of loading as a function of time. The localization method proposed is based on the maximum strain amplitude measured by FBG sensors during impact and the relative placement of all sensors. The force time history of impact loading on composite wing is predicted using a support vector regression (SVR) approach. A time delay embedding feature extraction scheme is used since it can resolve the dynamics of the impact using the sensor signal from the FBGs. Experimental validation is presented on graphite/epoxy composite wings with accurate localization and estimation results along the span of the wing.