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Arruda and Boyce proposed a model for the deformation of rubber materials [3]. Their main motivation was to develop a model that accurately captures the behavior of rubbers in different loading scenarios and that can be described with a limited number of physically motivated parameters. Their model is based on the Langevin chain statistics, which models a rubber chain segment between chemical crosslinks as a number $N$ of rigid links of equal length $l$ . The parameter $N$ is related to the locking stretch $\lambda_{L}$ , the stretch at which the chains reach their full extended state, $\lambda_{L}=\sqrt{N}$ .