Damage characterization in non-isothermal stretching of acrylics. Part I: Theory

An improved version of dual-mechanism constitutive model was proposed to describe thermo-mechanical response of amorphous polymers below and above glass transition temperature (θ_g). Material property definitions and plastic flow rules were revisited to provide a smooth and continuous transition in material response around θ_g. The elastic-viscoplastic constitutive model was developed based on thermodynamics framework and was implemented in a fully coupled thermo-mechanical simulation of non-isothermal testing of PMMA in Part II [Gunel, E. M.; Basaran, C.; 2010. Damage characterization in non-isothermal stretching of acrylics. Part II: Experimental validation. Mechanics of Materials]. For damage evolution in complex thermo-mechanical problems such as polymer processing operation, irreversible entropy production was considered as the measure of damage.