Distortion Index for Assessment of Damage Growth in a Composite Structures Using Spectral Distortion of Embedded FBG Sensors

Abstract

Structural Health Monitoring Systems based on embedded FBG sensors, to identify damage conditions, are largely dependent on the spectral distortion of the sensors. The uneven stress gradient occurring along the grating of FBG sensors, due to damage inside composite structures can be estimated by analyzing significant changes that appear in the FBG response spectra. However, the stochastic nature of the distorted shape of the FBG spectra makes it difficult to interpret and quantify the existing damage at the location of the FBG sensors. This research works on a novel concept of the “Distortion Index (DI)†which is defined using distorted spectra of FBG sensors. It was observed that the DI increases with the increase in damage size.