A generalized coupled viscoplastic-viscodamage-viscohealing theory for glassy polymers

Abstract

A thermodynamic consistent, small-strain, non-unified model is developed to capture the irregular rate dependency included in the strain controlled inelastic responses of polymers at the glassy state. The model is considered as a generalized Frederick-Armstrong-Philips-Chaboche (FAPC) theory proposed by Voyiadjis and Basuroychowdhury (1998) and Voyiadjis and Abu Al-Rub (2003) which is based on a von Mises and Chaboche isotropic hardening type viscoplasticity formulation. Using the proposed model, different experimental results are simulated and the range of viscoplastic related material constants are obtained through a parametric study. The thermodynamic framework is used to incorporate the effect of coupling between viscodamage and viscohealing phenomena into the inelastic deformation of glassy polymers. This coupling effect is crucial for polymeric based self healing systems in which different damage mechanisms are active and the efficiency of the healing processes are highly dependent on the damage. The computational aspect for general coupled inelastic-damage-healing processes together with the required solution algorithms are elaborated and the inelastic-damage-healing response of a polymeric based self-healing system is simulated. The proposed viscoplasticity theory constitutes a physically consistent approach to model the irregular mechanical responses of glassy polymers and the viscodamage model provides an exquisite predicting tool to evaluate the ductile damage associated with the large inelastic deformation and low cycle fatigue in polymeric based material systems. In conclusion, a well structured viscohealing theory is formulated for polymeric based self healing systems. (C) 2011 Elsevier Ltd. All rights reserved.