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Proceedings Paper

Determination of forming limits of sheet metals by speckle interferometry
Author(s): C. Vial-Edwards; B. Guelorget; Manuel Francois; Ignacio Lira; M. Münzenmayer
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Paper Abstract

Forming Limit Diagrams (FLD’s) can be defined by the criteria of either diffuse or localized necks. We used Electronic Speckle Pattern Interferometry (ESPI) in commercial 1100 aluminum sheet metals annealed at 400°C to determine the strains at which both types of neck started in uniaxial tension (U) and in quasi plane strain tension (PS) tests. In biaxial (B) loading we observed only the localized neck, but we were also able to detect a small defective spot at which fracture was incubated. The strains that produced the diffuse neck and the defective spot were approximately comparable to those predicted by Swift’s criterion for plastic instability. The difference between the FLD defined by a diffuse neck or by a defective spot leading to fracture and the one defined by a localized neck was found to be very noticeable in the U tests and less important, but still significant, in the PS and B tests. We found also that maximum load occurred at some point within the diffuse neck region and that afterwards the load carrying capacity was still substantial. We thus conclude that the decision on the criterion to use should be based on parts quality, safety and costs.

Paper Details

Date Published: 14 February 2005
PDF: 10 pages
Proc. SPIE 5776, Eighth International Symposium on Laser Metrology, (14 February 2005); doi: 10.1117/12.611711
Show Author Affiliations
C. Vial-Edwards, Pontificia Univ. Catolica de Chile (Chile)
B. Guelorget, LASMIS, CNRS-Univ. de Technologie de Troyes (France)
Manuel Francois, LASMIS, CNRS-Univ. de Technologie de Troyes (France)
Ignacio Lira, Pontificia Univ. Catolica de Chile (Chile)
M. Münzenmayer, Pontificia Univ. Catolica de Chile (Chile)


Published in SPIE Proceedings Vol. 5776:
Eighth International Symposium on Laser Metrology
R. Rodriguez-Vera; F. Mendoza-Santoyo, Editor(s)

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