FEM prediction of self-heating and thermal softening in semicrystalline polymers using a unified two-phase intermolecular resistance constitutive model

The constitutive modelling of semi-crystalline polymers (SCPs) has to consider several aspects as rate- and temperature- dependencies, self-heating, and in particular, the double yield (DY) phenomenon. Full characterization of all these complex features involves huge efforts in terms of material parameter identification. The contribution of the crystalline phase plays an important role in the evolution of the plastic yield in the SCPs. In this work, a constitutive model, named unified semi-crystalline polymer (USCP), is proposed by modifying the physical-based Boyce-Park-Argon (BPA) glassy model [1]. The contribution of the crystalline phase is introduced in the strain softening/hardening evolution law of the athermal strength. This proposed evolution provides an alternative interpretation of the underlying morphological changes caused by the crystalline phase embedded in the amorphous phase. The proposed formulation relies on the phenomenological equation postulated in [1-3] and is further extended with an additional and new contribution to capture the crystalline phase. A full thermo-mechanical coupled FEM-based framework is developed for the USCP model validation. The DY phenomenon at different strain rates with self-heating and thermal softening effects can be accurately predicted. The material parameter identification procedure requires direct usage from the stress-strain curves [3] where only three more physical-based parameters are needed. The model predicts very well the experimental results obtained by different authors [4-5]. REFERENCES [1] M.C. Boyce, D. M. Parks and A. S. Argon, Mechanics of Materials,7:15-33,1988. [2] K. A. Chowdhury, A. A. Benzerga and R. Talreja, Comput. Methods Appl. Mech. Engrg., 197:4485–4502, 2008. [3] X. Poulain, A. A. Benzerga and R. K. Goldberg, Int. J. Plast, 62:138-161, 2014. [4] A. S. Khan and B. Farrokh, Int. J. Plast, 22:1506–1529, 2006. [5] E. Parodi, G. Peters and L. Govaert, Polymers, 10:710-719, 2018.

Jaar van publicatie:2022

Toegankelijkheid:Closed