Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run - part 1: measurement of strain

Abstract Optical fibre strain and shape measurement sensors were deployed on a 5-m long rotor blade during full-speed (rotation rate 6.6 Hz) helicopter ground run, with real-time data wirelessly streamed from hub-mounted sensor interrogators. In Part 1 of 2-part paper series, the sensing capabilities two optical fibre-based techniques, Bragg grating (FBG) segment interferometry (FSI), are compared, while 2 (Kissinger et al 2022 Smart Mater. Struct. accepted) specifically investigates based FSI approach. part 1, instrumentation is described, dynamics obtained sequence controlled pilot inputs analysed both in time spectral domains. It shown that this can provide insights into aeroelastic properties blade. Noise standard deviations 0.2 n ϵ / $\sqrt{\text{Hz}}$?> Hz 30 for FBG-based approaches, respectively, observed over range 3500 µϵ .