Biaxial hot drawing of poly(ethylene terephthalate): measurements and modelling of strain-stiffening

Effects of crystal content on the mechanical behaviour of polyethylene under finite strains: Experiments and constitutive modelling

“…Because of the complexity of the problem and due to the lack of a real understanding of the elementary deformation mechanisms, several authors relied on purely phenomenological models (Bardenhagen et al, 1997;Khan and Zhang, 2001;Zaïri et al, 2005aZaïri et al, ,b, 2007Zaïri et al, , 2008Colak, 2005;Ben Hadj Hamouda et al, 2007;Pyrz and Zaïri, 2007;Dusunceli and Colak, 2008;Ghorbel, 2008;Drozdov, 2009;Regrain et al, 2009). As an alternative, physically-based models were also proposed (Boyce et al, 1988(Boyce et al, , 2000Arruda et al, 1995;Buckley and Jones, 1995;Wu and van der Giessen, 1995;Tervoort et al, 1997;Adams et al, 2000;Ahzi et al, 2003;Anand and Gurtin, 2003;Makradi et al, 2005;Anand and Ames, 2006;Dupaix and Krishnan, 2006;Richeton et al, 2007;Ames et al, 2009;Anand et al, 2009;Belbachir et al, 2010;Ayoub et al, 2010;Zaïri et al, 2010Zaïri et al, , 2011. To date, most modelling efforts have been devoted the case of amorphous polymers and the physically-based models were inspired from the early work of Haward and Thackray (1968) connecting both yielding and strain hardening due to the evolution of the macromolecular network structure.…”

On the modelling of highly elastic flows of amorphous thermoplastics

“…the spin) should be apportioned between viscous flow and elastic deformation, have cautiously declined to speculate on this point and their proposed models are incomplete in this respect (Vigny et al 1999;Adams et al 2000;Dooling et al 2002;Makradi et al 2005). …”

Modelling of morphology evolution and macroscopic behaviour of intercalated PET–clay nanocomposites during semi-solid state processing

“…Physical background and mathematical details of the model along with the values of relevant model parameters can be found in [6]. The PET model can capture the macroscopic strain-stiffening behaviour of the PET and its nanocomposite (see Section 4) -that phenomenon is associated with the onset of pre-crystallinity, which is a pre-cursor to the stress-induced crystallization [15]. The phenomenon is described here in terms of the parameter v (see [6] for more details), which assumes a value of 0 when PET matrix undergoes a viscous flow -it is equal to 1, when the viscous flow in PET is arrested (onset of pre-crystallinity) and causes the onset of macroscopic strain-stiffening [6].…”