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Proceedings Paper

Study of internal deformation fields in granular materials using 3D digital speckle x-ray flash photography
Author(s): Stephen G. Grantham; William G. Proud; Howell Timothy Goldrein; John E. Field
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Paper Abstract

A method of visualising the 3-dimensional flow field within an opaque material has been developed using the principle of digital speckle photography combined with flash X-rays. The speckle pattern is achieved by seeding the specimen with a plane of lead filings and using X-rays to image the pattern before and during an impact event. Utilising a flash X-ray machine, the 2-dimensional components of displacement can be measured throughout the seeded plane. Thus, by repeating the experiment changing the times of the X-ray flashes and the location of the seeded plane, the full 3-dimensional displacement field within the specimen during the event can be deduced. The displacement sensitivity of the system is currently approximately 50 µm and the spatial resolution approximately 1 mm. Our current X-ray system gives an exposure time of 30 ns. The system has been successfully tested on polyester and cement samples but is here extended to the study of loose granular materials, in particular sand. This allows us to investigate material behaviour in a way not previously possible and in this paper we present the deformation caused by an impact from a fast-moving projectile.

Paper Details

Date Published: 7 March 2006
PDF: 8 pages
Proc. SPIE 4101, Laser Interferometry X: Techniques and Analysis, (7 March 2006); doi: 10.1117/12.498392
Show Author Affiliations
Stephen G. Grantham, Univ. of Cambridge (United Kingdom)
William G. Proud, Univ. of Cambridge (United Kingdom)
Howell Timothy Goldrein, Univ. of Cambridge (United Kingdom)
John E. Field, Univ. of Cambridge (United Kingdom)


Published in SPIE Proceedings Vol. 4101:
Laser Interferometry X: Techniques and Analysis
Gordon M. Brown; Malgorzata Kujawinska; Werner P. O. Jueptner; Ryszard J. Pryputniewicz; Ryszard J. Pryputniewicz; Mitsuo Takeda, Editor(s)

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