High-speed interrogation of multiplexed Fiber Bragg gratings enabling real-time visualization of dynamic events such as impact loading

Fiber Bragg gratings (FBGs) are widely recognized for their unobtrusive sensing character and multiplexing possibilities. Within this article, these advantages are fully exploited through the development of a high-speed full-spectral FBG interrogation system capable of simultaneously reading out a range of FBG sensors. For the first time, the full-spectra of multiplexed FBG sensors are dynamically interrogated up to 100 kHz with a spectral resolution down to 40 pm. The feasibility of this unique sensing system is demonstrated using carbon fiber integrally stiffened panels which are monitored for their structural health. Detailed analysis based on the full-spectral datasets is enabling the assessment of non-linear events involving non-uniform strain distributions, such as impact loading. Moreover, we show real-time visualization of these impact events based on the multiplexed FBG responses.