The effects of thermomechanical coupling on the cold drawing process of glassy polymers

Abstract

The source and the effects of strain-induced heating on the stress-strain behavior and corresponding cold drawing process of glassy polymers are investigated. The nature of dissipative and stored components of work are discussed where only 50 to 80% of the mechanical work of glassy polymers has been found to be dissipative. This phenomenon is demonstrated to be well-modeled by considering a portion of the work to be stored as strain-induced molecular orientation in the polymer that evokes a back stress tensor. The results of the modeling are found to be consistent with experimental measurements reported in the literature. The constitutive and corresponding heat generation model are used in fully thermomechanically coupled finite element analysis of the cold drawing of glassy polymers. The influence of applied elongation rate on the resulting temperature rise, heat transfer, thermal softening, and fiber geometry are presented, together with a full complement of the deformation field parameters related to the propagating shoulders of the drawn neck.

Micromechanical modeling of the tensile behavior of oriented polyethylene

“…The Arruda-Boyce eight-chain network model of rubber elasticity 32 was used to account for orientation-induced strain hardening. 33,34 …”

Multiscale Modelling of the Mechanical Behaviour of Oriented Semicrystalline Polymers

“…The plastic rate of stretching is defined by an associated flow rule. The Arruda-Boyce eight-chain network model of rubber elasticity [12] is used to account for orientation-induced strain hardening [13,14].…”

Post-yield compressed semicrystalline poly(butylene terephthalate): energy storage and release

“…Robertson [40], Argon [41], and Boyce et al [42] suggest that the stored energy could be a consequence of distorting or rotating chain segments under the action of shear components of stress ('liquid-like' approach). On the other hand, Bowden [43], Oleynik [15, 17 -19], Perez [44], and G'Sell [13,45] ascribe the process to inhomogeneous and localized shear transitions or shear defects rather like dislocations in crystals ('crystal-like approach').…”

“…On the other hand, Bowden [43], Oleynik [15, 17 -19], Perez [44], and G'Sell [13,45] ascribe the process to inhomogeneous and localized shear transitions or shear defects rather like dislocations in crystals ('crystal-like approach'). Some constitutive models have been also recently proposed to describe the enthalpy recovery in both amorphous and semicrystalline polymers [42,46,47].…”