Simulation of the stretch blow moulding process: from the modelling of the microstructure evolution to the end-use elastic properties of polyethylene terephthalate bottles

Abstract

The whole stretch blow-moulding process of PET bottles is simulated at the usual process temperature in order to predict the elastic end-use properties of the bottles. An anisotropic viscoplastic constitutive law, coupled with microscopic variables, is identified from uniaxial tensile tests performed at different strain rates and temperatures. The microstructure evolution is characterised by crystallinity measurements from interrupted tests and frozen samples. For each specimen tested, the Young modulus is measured at room temperature. Numerical simulations of the blow moulding process are run using the C-NEM method. A micromechanical modelling is post-processed after the simulation to predict the elastic properties. Predictions of Young modulus distributions in bottles are in agreement with the ones measured on blow-moulded bottles.