Modelling of self-healing in viscoelastic materials

A novel viscoelastic damage-healing model for self-healing materials is proposed coupling continuum damage healing mechanics (CDHM) framework with a viscoelastic constitutive model for self-healing during unloading and rest periods. The viscoelastic damage-healing model is coupled with the novel secondary damage internal variable accounting for the subsequent damage of healed material. The proposed viscoelastic damage-healing model formulation is numerically implemented by return mapping approach employing the elastic strain equivalence hypothesis from CDHM, and model response as stress update is obtained for several strain histories. Detailed parametric studies are conducted by varying the material constants appearing in the damage and healing evolution equations, and their influence on the constitutive model response is analysed. Various tangent moduli expressions are finally derived, and successfully coupled with an in-house developed plane strain nonlinear finite element code while solving different boundary value problems.