8 – Viscoplasticity Models

Viscoplasticity models are the ultimate models for polymer modeling, both in terms of accuracy and complexity. Some of the models of this category are truly impressive at predicting the non-linear, time- and temperature-dependent response of various polymers. The downsides of these models are that they typically require more experimental data for proper calibration, they can be numerically expensive, and typically require additional software components (user subroutines, like UMATs and VUMATs, see Chapter 10). The field of viscoplastic constitutive modeling is evolving, and new models are developed every year by different research groups. This chapter attempts to present some of the most useful models that are available for different polymers, and the trends of where this field is going in the future.