Constitutive modelling of a self-healing composite matrix polymer material

In this work, a constitutive model of an intrinsically self-healing composite matrix material is presented. The developed model comprises a micro-damage initiation and evolution model, and a healing evolution model, which are combined with the von Mises linear isotropic hardening plasticity. It is implemented into the Abaqus/Standard user material subroutine UMAT and validated using experimental results of static tensile and two-cycle tensile tests performed on partially neutralised poly(ethylene-co-methacrylic acid) (EMAA) ionomer copolymer, Surlyn® 8940. In the development of the model, Continuum Damage Healing Mechanics (CDHM) concepts of nominal and healing configurations are used. In addition, these concepts are used along with the strain equivalence hypothesis to streamline the numerical implementation. The strain equivalence hypothesis relates strain and stress tensors in the nominal and the healing configuration. Finally, successful validation has shown that the developed model is able to accurately predict behaviour of Surlyn® 8940 coupons during tensile tests and it can precisely predict the accumulation of plastic strain.