Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability

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Volume 2, Issue 6 (November 1974)

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ISSN: 0090-3973
Page Count: 6

Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability
Hsü, TC
Professor of applied mechanics, University of Aston,

Abstract

The distinction between coaxial and noncoaxial strains is explained. It is shown that with noncoaxial strains deformation does not necessarily produce a change of shape, if circles and ellipses are used for strain measurements. If materials are tested in exisymmetrical processes, in which the strains are coaxial, and used in unsymmetrical ones, in which the strains are noncoaxial, then the formability will appear to be overestimated. A test for coaxiality, based on the use of squares and parallelograms for the strain measurements, is presented in the text and the formula used is derived in the Appendix.

Keywords:
strains, deformation, ductility, formability, metal sheets, forming, sheet metal test, strain paths, change in shape, grids

Paper ID: JTE11689J
DOI: 10.1520/JTE11689J
ASTM International is a member of CrossRef.

Author Title Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability Symposium , 0000-00-00 Committee E28

		Home Journals STPs Manuals Topics Subscriptions/Pricing Digital Library / Journals / Journal of Testing and Evaluation (JTE) / Citation Page Volume 2, Issue 6 (November 1974) Click here to download this paper now for $25 PDF (168K) View License Agreement ISSN: 0090-3973 Page Count: 6 Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability Hsü, TC Professor of applied mechanics, University of Aston, Abstract The distinction between coaxial and noncoaxial strains is explained. It is shown that with noncoaxial strains deformation does not necessarily produce a change of shape, if circles and ellipses are used for strain measurements. If materials are tested in exisymmetrical processes, in which the strains are coaxial, and used in unsymmetrical ones, in which the strains are noncoaxial, then the formability will appear to be overestimated. A test for coaxiality, based on the use of squares and parallelograms for the strain measurements, is presented in the text and the formula used is derived in the Appendix. Keywords: strains, deformation, ductility, formability, metal sheets, forming, sheet metal test, strain paths, change in shape, grids Paper ID: JTE11689J DOI: 10.1520/JTE11689J ASTM International is a member of CrossRef. Author Title Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability Symposium , 0000-00-00 Committee E28