Experimental and Modelling of Shape Memory Effect of Shape Memory Natural Rubber

Shape memory natural rubber (SMNR) is a form of smart material that can memorise its permanent shape in response to temperature. In this article, a phenomenological constitutive model was adopted to predict the stress-strain evolution during the shape memory process of SMNR to understand the behavior of SMNR. A standard linear solid (SLS) model with Kelvin Voigt element was extended with two Mooney Rivlin models to account for the mechanical response, while a thermal strain model represented the change of length during the programming process and recovery process. An external temperature law was constructed to govern the volume fraction change between the soft active and frozen phase. The proposed constitutive model is capable of capturing the stress-strain behaviour of each shape memory step.