Constitutive model of cold drawing in polycarbonates

Arif Masud, Alexander Chudnovsky

Research output: Contribution to journalArticlepeer-review


This paper presents a set of constitutive equations to model cold-drawing (necking) in polycarbonates (PC). The model is based on a representation of cold drawing as a double glass transition, i.e., a transition from a glass into a rubbery state, when a certain yield surface in the stress space is reached, and a transition back to the glassy state upon unloading or when a certain molecular orientation (draw ratio) is achieved. The stretching process in the rubbery state is modeled by a hyperelastic extension of the J2-flow theory to the finite strain range. An appropriate yield surface and an associative flow rule (defined via the Kuhn-Tucker optimality conditions) are presented to simulate this process in polycarbonates. The isochoric constraint during double glass transition is treated via an exact multiplicative decomposition of the deformation gradient into volume preserving and spherical parts. Numerical constitutive integration algorithm is based on an operator splitting technique where constraint/consistency during inelastic deformation is enforced via return mapping algorithm. Numerical results are presented to demonstrate the correspondence with the experimental data.

Original languageEnglish (US)
Pages (from-to)1139-1157
Number of pages19
JournalInternational journal of plasticity
Issue number11
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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