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Mapping full field deformation of auxetic foams using digital speckle photography
Author(s) -
Chiang Fupen,
Uzer Gunes
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200880254
Subject(s) - materials science , strain gauge , composite material , deformation (meteorology) , speckle pattern , digital image correlation , rigidity (electromagnetism) , optics , physics
Measuring strain in foam presents a number of challanges. In the case of polymeric foam, the material is so soft that a conventional strain gage is not applicable because the rigidity of gage and its associated glue is stronger than the foam itself. Transducers such as clip gage, etc. may not be suitable either because the strain field may not be uniform within the gage length. Thus it is desirable that a non‐contact and full field strain measurement technique be available. In this paper we introduce a speckle photography technique that is non‐contact and can measure the full field deformation of a foam specimen. We use the natural texture of the pattern. Digitized images of the foam specimen under different loads are “compared” using a special algorithm called CASI, to yield deformation maps of the specimen. Examples of applying this technique to testing PVC foam composites are presented in the paper. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)