A Two-Phase Model for the Mechanical Behavior of Semicrystalline Polymers

L. Cangemi (1) , Y. Meimon (1)

1 IFPEN - IFP Energies nouvelles

The increasing use of semicrystalline polymers (SCP) in complex industrial structures, requires the development of reliable and predictive mechanical behavior models. The various approaches developed in the literature are considered and experimental results obtained from tests on PVF2 and on PA11 are presented. These results show that these polymers are sensitive to the mean stress, and that the volume strain cannot be neglected and should be taken into account to model the material behavior. From the mechanical models existing in the literature, one can define three categories according to the scale of representation used (micro, meso and macro) and the information which they allow to extract from the microstructure. It turns out that the adoption of an intermediate meso-scale constitutes a good compromise between theoretical difficulties and richness of modeling. This pragmatic choice leans on a two-phase representation of SCP, who allows to make a continuous transition from the microscopic scale to the macroscopic scale. The thermodynamics of open systems leads to introduce a mechanical coupling equation between a solidphase (including the crystal) and a softphase or a fluidphase (essentially amorphous). The model is then completed by an elastoviscoplastic formulation allowing to describe the particular volume strain of SCP, the effects of the loading rate and of the mean stress. The model is validated against results of tension tests carried out on these two types of SCP used in the oil industry.

Domains: Physics [physics]

L. Cangemi, Y. Meimon. A Two-Phase Model for the Mechanical Behavior of Semicrystalline Polymers. Oil & Gas Science and Technology - Revue d'IFP Energies nouvelles, 2001, 56 (6), pp.555-580. ⟨10.2516/ogst:2001045⟩. ⟨hal-02053961⟩