Rate- and temperature-dependent strain hardening of polycarbonate

The modeling and quantification of a viscous contribution to strain hardening is discussed. Traditional strain hardening models, based on rubber-elasticity, show serious deviations from the experimentally observed large-strain response of glassy polymers. Therefore, to capture both the strain rate and temperature dependence of strain hardening correctly, a part of the rubber-elastic strain hardening is replaced with a viscous contribution. This is realized by introducing a deformation-dependent viscosity in the Eindhoven Glassy Polymer model. Verification of the accuracy of the model proposed is done using a set of uniaxial compression tests on polycarbonate at different strain rates and temperatures. An accurate description of all experimental data results and, moreover, the model quantitatively captures the Bauschinger effect observed in oriented polycarbonate. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012