In Situ Measurement of the Fragmentation Behavior of Al/PTFE Reactive Materials Subjected to Explosive Loading, Part 2: Fragment Velocity and Trajectory Measurements

Abstract

High‐speed optical diagnostics and image analysis methods are applied to implement an automated Kalman filter based tracking technique to measure fragment size, velocity, and trajectories for studying the fragmentation behavior of explosively launched Al/PTFE cylinders. Bivariate histograms of equivalent spherical diameters of fragments greater than 1 mm and their corresponding velocities are presented to describe the explosively‐driven fragmentation behavior of several Al/PTFE specimens. Spatial cross‐correlation of fragments is also implemented to optically determine, from high‐fidelity high‐speed images, the spatial distribution of fragment trajectories inside the diagnostic section. Sizes determined from the Kalman filter based tracking process are compared with the sizes determined from the high‐fidelity measurements in Part 1. Similarly, the velocities of discretely tracked fragments are compared to velocity estimates from the bulk fragment displacement calculated using a phase correlation routine.