Dynamic measurements of internal three-dimensional displacement fields with digital speckle photography and flash x rays.
A metrology system is presented that measures internal three-dimensional (3-D) displacement fields. The system uses a stereo pair of flash x-ray heads and correlation analysis to measure the true deformation of a layer of x-ray-absorbent particles inside the specimen. The 3-D deformation field inside blocks of polyester was determined. The polyester blocks were impacted by a 9-mm steel ball bearing fired from a 9-mm-bore gas gun at a speed of 373.5 +/- 3.0 m s(-1). At a given time after impact, a short-duration (30 ns) flash x-ray pulse exposes the x-ray radiographs and freezes the events during impact. Thereafter, the x-ray radiographs are scanned into a personal computer and analyzed as in digital speckle photography.
Synnergren
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Physics and Chemistry of Solids, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom. pelle@mt.luth.se
Goldrein
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