Internal Displacements in Cement during Ballistic Impact.

The technique of Digital Speckle Radiography (DSR) has been shown to be widely applicable to the field of ballistics through its ability to measure internal displacement fields to a high precision. In a DSR experiment, a flat plane, typically 500 μm thick, of X-ray opaque filings are introduced into the sample during manufacture. Flash X-rays can then be used to image the plane, both before and during an impact event, to produce random speckled images on an X-ray film. Small sub-regions of the images can be tracked relative to each other using a Digital Speckle Photography (DSP) correlation algorithm. This produces a displacement field within the specimen on the seeded plane. By repeating an experiment with identical specimens, but varying the delay of the X-ray exposure, a full time history of the impact event can be obtained. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]