Simulation of Free Blowing of Polyethylene terephthalate Using a Thermodynamic Induced Crystallisation model
Résumé
Microstructure evolution in Poly(Ethylene Terephthalate) during a blowing process has an important influence on final mechanical property (Chevalier,1999). In order to simulate blow-moulding process it is necessary to take into account this evolution. In a first part we present a thermodynamic model in the case of a simple dependence of the viscosity under the crystallisation ratio (Poitou, 2001). The model is identified on uniaxial and biaxial tension tests results. In a second part, the axisymmetric problem of membrane inflation is solved using a classical finite element technique. The simulated results are compared with experimental results on free blown preforms and the comparison is quite accurate considering the elementary form of the induced crystallisation model.