Paper Titles
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Through-Process Texture Simulation for Aluminium Sheet Fabrication
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Influence of Spatial Grain Orientation Distribution on Sheet Metal Necking
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A Suitable Criterion for Precise Determination of Incipient Necking in Sheet Materials
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Evaluation of Biaxial Forming Limits by Bulge Testing
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A Suitable Criterion for Precise Determination of Incipient Necking in Sheet Materials

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Abstract:

Forming limit diagram (FLD) is a measure of the formability of a sheet material. The major-minor strain pairs that are closest to the neck on multiple specimens of various strain paths are utilized to construct a boundary between safe and unsafe zones. The challenge to obtain the FLD is the determination of incipient necking. Three approaches to determine the limit strains have been investigated and compared in this research in order to establish the optimal one for implementation: (1) commonly used Bragard criterion ( 1)e Br with periodic grids; (2) tracking the region of large local strains from strain history to locate the instance when critical major strain ( 1)e cr happens; (3) post-processing of strain history to locate the inflection in the major strain rate curve 1 max (e&&) at the onset of localization. The last criterion of inflection in strain rate 1 max (e&&) carries both a numerical and a physical meaning towards developing an understanding of flow localization, formability and fracture.

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Periodical:

Materials Science Forum (Volumes 519-521)

Pages:

111-116

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.519-521.111

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Online since:

July 2006

Authors:

Q. Situ, Mukesh K. Jain, M. Bruhis

Keywords:

Bragard Criterion (ε1)Br, Critical Major Strain (ε1)cr, Forming Limit Diagram (FLD), Maximum Major Strain Acceleration (ε1)max

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© 2006 Trans Tech Publications Ltd. All Rights Reserved

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References

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