Modeling thermal recovery of the Mullins effect

Many elastomeric materials exhibit the Mullins effect, or stretch-induced stress softening. However, early experiments show that the Mullins effect may be recovered after annealing previously stretched material in a stress-free state. And that both the rate and degree of recovery are affected by the annealing temperature. In this work, we develop a thermo-mechanically-coupled large-deformation constitutive model that quantitatively captures thermal recovery of the Mullins effect. The model is calibrated to experiments from the literature, and is numerically implemented by writing a user material subroutine for the finite element program Abaqus/Standard. Lastly, our simulation results suggest that unanticipated behavior due to recovery of the Mullins effect is possible.