Get access
Advertisement

A multiprocess eyring model for large strain plastic deformation

Authors

  • P. Olley,

    Corresponding author
    1. School of Engineering Design and Technology, IRC in Polymer Science and Technology, University of Bradford, Bradford BD7 1DP, United Kingdom
    • School of Engineering Design and Technology, IRC in Polymer Science and Technology, University of Bradford, Bradford BD7 1DP, United Kingdom
    Search for more papers by this author
  • J. Sweeney

    1. School of Engineering Design and Technology, IRC in Polymer Science and Technology, University of Bradford, Bradford BD7 1DP, United Kingdom
    Search for more papers by this author

Abstract

A multiprocess Eyring model is developed with a particular aim of predicting the localized instability occurring in “necking” polymers when cold-drawn. Differences from using single and multiple Eyring processes are examined using a published data-set for polypropylene test pieces; it is shown that a four Eyring process model can simultaneously fit both necking stretch ratio and draw force data for uniaxial stretching, whereas with a single process only one measurement could be fitted accurately. The multi process Eyring model is shown to give significantly more accurate predictions than a necking hyperelastic model. The multiprocess model is assessed against the same material undergoing a complex constant-width elongation. It is shown that agreement is quantitatively good for both drawing force and surface deformation, with some minor differences in transverse force and surface stretch. A pronounced intermittent stretching pattern that is seen on the experimental test piece is replicated by the multiprocess Eyring simulation, but is absent using the hyperelastic model. A method is described to deform a photograph of the original specimen according to a finite element solution. The method is shown to give a clear indication of the accuracy of the model in predicting final form. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Get access to the full text of this article

Ancillary