New theoretical model for predicting limit strains in the punch stretching of sheet metals

J. Chakrabarty, Wing Bun Lee, Kang Cheung Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


An initial non-uniformity in thickness of a sheet metal, which is commonly assumed as a basis for the theoretical prediction of limit strains in the biaxial stretching process, is considered here as a feature of the mathematical idealization of a complex process, rather than as a material imperfection existing in a real sheet metal. The present concept permits the degree of initial inhomogeneity to vary with the stress ratio, as well as with the mechanical properties of the material. When such a variation is allowed for in a suitable manner, the predicted forming limit curves exhibit a relatively small dependence on the degree of normal anisotropy of the sheet metal, and follow a trend that is in agreement with what is observed experimentally. The results demonstrate the importance of the non-quadratic yield function when dealing with sheet metals with a range of R-values of less than unity.
Original languageEnglish
Pages (from-to)257-263
Number of pages7
JournalJournal of Materials Processing Technology
Issue number1
Publication statusPublished - 30 Jun 1999

ASJC Scopus subject areas

  • Ceramics and Composites
  • Computer Science Applications
  • Metals and Alloys
  • Industrial and Manufacturing Engineering


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