A fiber optic sensors system for load monitoring on aircraft landing gears

We report on the use of Fiber Bragg Grating (FBG) sensors integrated onto an aircraft landing gear for remote and realtime load monitoring. Several FBGs strain sensors, both in a linear and tri-axial configuration, have been integrated on different locations of true landing gears (both Main and Nose gears) based on their load condition derived from FEM numerical analysis and exposed to numerous qualification lab tests where the load applied to the gears was varied in the range 0-20kN. To this aim, the gears were mounted on a 25kN hydraulic press, that changed the shock absorber route from 0 mm up to 200 mm (corresponding to the maximum take-off weight,~4600 kg). Obtained results are in good agreement with those provided by reference electrical strain gauges located very close to their optical counterparts, and demonstrate the great potentialities of FBG sensors technology to be employed for remote and real time load measurements on aircraft landing gears.