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This paper studies the influence of diverse friction models on the numerical analysis of an industrial skew rolling mill using FORGE®. The originality of the present contribution is the analysis of the effect of the friction model on important parameters, namely, consumed power, plastic deformation and surface temperature. The aim is to evaluate which of these friction models is appropriate for simulating these industrial processes. The high values of temperature, pressure and sliding velocity at the contacts make the assessment of the friction model incidence on the deformation and temperature evolution fundamental, given its importance on the thermomechanical processing of materials. As a conclusion, IFUM is not valid because of its sliding velocity approach. On the other hand, Neumaier presents the highest deviations in terms of experimental power. It is concluded that Tresca is valid for this sort of processes and Norton model gives the most accurate results for friction power, related to the high sliding conditions at the contact. [ABSTRACT FROM AUTHOR]

Shape-memory polymers (SMPs) represent a class of smart materials able to store a temporary shape and to recover the original shape upon an external stimulus, such as temperature. The present paper proposes a three-dimensional finite-strain phenomenological model for thermo-responsive SMPs, which distinguishes between two material phases presenting different properties and is based on a rule of mixtures. The proposed model is motivated by the earlier work of Reese et al. (2010) and it considers several significant material features that had not been addressed in previous phenomenological approaches. Specifically, the model reproduces both heating-stretching-cooling and cold drawing shape-fixing procedures and it takes into account the non-ideal behavior of realistic SMPs (i.e. imperfect shape-fixing and incomplete shape-recovery). Several numerical tests are reported to assess model performances, from simple uniaxial and biaxial tests to complex simulations of biomedical devices. Comparisons with experimental data taken from the literature are also provided to validate the model. The proposed improvements increase the model applicability over a wide range of polymer types and operating conditions. [ABSTRACT FROM AUTHOR]