A 1D micromechanics-based constitutive model for the thermoviscoelastic behavior of crosslinked semicrystalline shape memory polymers: numerical simulation and experimental validation

The paper develops a 1D thermoviscoelastic constitutive model for the crystallization- and melting-induced one-way and two-way shape memory effects, as well as isothermal yielding behaviors, of crosslinked semi-crystalline polymers. A micromolecular chain model is proposed to characterize the transition between the amorphous and crystalline phases. Structural equations including a modified Eying model that combine phase transition and viscoelasticity equations are employed to predict the shape memory effects. An extensive experimental campaign has been carried out on poly (ethylene-co-vinyl acetate) based semi-crystalline elastomers to characterize the thermoviscoelastic temperature-stress-strain relations of the material under different loading and rate conditions. Some results guide the determination of the model parameters, while the rest validate the model capabilities. Comparisons with the experimental results show that the model can well reproduce the stress-strain-temperature responses, providing valuable insights for application development.