Computational assessment of residual formability in sheet metal forming processes for sustainable recycling

Javad Falsafi, Emrah Demirci, Vadim Silberschmidt

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
43 Downloads (Pure)


This paper introduces a new computational scheme addressing a problem of cold recyclability of sheet–metal products based on the assessment of their post-manufacture residual formability. Formability of sheet metals has been studied for several decades, and various techniques were suggested since a Forming Limit Diagram was first introduced in the 1960s. At the same time, cold recycling, or re-manufacturing, of sheet metals is an emerging area studied mostly empirically; in its current form, it lacks theoretical foundation. In order to address the challenge of residual formability for sheet-metal products, a reformability index is introduced in this study. The proposed method takes advantage of the latest developments in the area of evaluating multiple-path formability and introduces a quantitative re-formability index for the manufactured material. This index represents possible levels of strains for deformation along different paths, based on Polar Effective Plastic Strain (PEPS). PEPS provides robustness against non-linear strain-path effects, thus making a reliable basis for such analysis. Based on residual formability, a predictive model was sought to assess a degrading effect of the flattening process. Taking advantage of extensive numerical simulation, a wide range of geometrical parameters in an unbending process, as a predominant mechanism in flattening, was studied.
The re-formability index alongside prediction of degradation in flattening allows evaluation of prospective re-manufacturing. The significance of this research is its advancement towards recycling of sheet-metal products without melting them by facilitating design for sustainability. The proposed scheme also provides a subroutine friendly framework for numerical simulations.
Original languageEnglish
Pages (from-to)187-196
Number of pages10
JournalInternational Journal of Mechanical Sciences
Early online date13 Oct 2016
Publication statusPublished - 31 Dec 2016


  • remanufacturing
  • sheet metal
  • residual formability
  • reformability index
  • flattening
  • Polar Effective Plastic Strain
  • cold recyclability
  • degradation prediction
  • numerical simulations


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