The study aimed at experimentally determining the influence of the viscoelasticity of the material on the soft elasticity phenomenon. I characterized the viscoelasticity with a master curve of the storage modulus, and the phase transition with uniaxial tensile tests at various strain rates and temperatures. Using the time-temperature superposition principle, we showed that the stress and strain values present a linear viscoelastic behavior. For these LCEs, the soft elasticity of the phase transition belongs to the transient part of the behavior. This also reveals the contribution of relaxation mechanisms originating from the liquid crystal orientation. These conclusions provided strong experimental evidence to support a modeling approach of the effective behavior of LCEs. 

In order to model the viscoelastic, soft elastic behavior of LCEs at room temperature, we are theoretically investigating the dissipation of LCEs to determine the coupling between the viscoelastic mechanisms and the soft elasticity. We expanded the Souza-Auricchio model developed for the superelasticity of Shape Memory Alloys to the soft elasticity of LCEs, integrating viscoelasticity as a coupled or decoupled behavior. A nonlinear generalized Maxwell model represents the relaxation time distribution, considering different combinations of soft elasticity and viscoelasticity effects. In the partially coupled model, some dissipation mechanisms are coupled and will not be active during soft elasticity while others remain decoupled and dissipate during the transition.