Streak Photography
augmented with Fibre Optics Cable for Detonics & Shock DynamicsOptical techniques using fast streak cameras are well established methods for studying shock wave and detonation phenomena. The use of fibre optics cable not only provides multidimensional view to a streak camera but also accesses the information either hidden inside the test specimen or obstructed by explosion debris. Competing with the latest advances in the diagnostic techniques, fibre optic-based experimental techniques have been developed forthe studies of detonics and shock propagation.
In velocity measurement mode, a number of optical
pins are fixed at the outer surface of a cylindrical explosive to record the arrival of
detonation wave at the pin locations. The other ends of the optical fibre cables are
arranged in a straight array for viewing by a high-speed rotating mirror streak camera
Distances of the optical pins from the explosive initiating are marked on the camera
record
Remote pin arrangement was made in which the fibre
collects the light from a distance and the optical pin does not disturb the motion
of the shocked surface. In remote pin arrangement, a number of flat-bottomed
cylindrical holes are drilled at different depths in a test specimen. Fibre cables
are fixed on the specimen's free surface to directly view the shock breakout at the
bottom of holes The distances of the bottom of cylindrical hole from explosive metal
interference are marked in the camera record. The depth of the hole determines the time
for which the shock luminescence remains visible to the fibre cab.