DETERMINATION OF ROUND EXIT VELOCITY USING FIBER BRAGG GRATING SENSORS

Abstract

Optical fiber sensing technology has found widespread applications in smart structures and intelligent engineering systems. In particular, the use of fiber Bragg grating sensors for strain, temperature and pressure measurement has been an area of active research in the past decade.

In this thesis, an experimental technique to measure the exit velocity of projectiles in field-deployed gun barrels is presented. In-fiber Bragg grating sensors are used to monitor the onset of propagating hoop strain waves accompanying the passage of rapidly moving projectiles. A fixed optical filter is used for providing temperature compensation and enable high-speed data acquisition. The elapsed time information extracted from the resulting strain waves is used to estimate the round exit velocity (REV). An approach based on short-time Fourier analysis and cross-correlation has been developed to accurately measure the REV to within 1% error. Results from live-fire tests are presented and compared to reference velocity data.