Force and multiple-shape-recovery in shape-memory-polymers under finite deformation torsion-extension

Abstract

This paper presents a general semi-analytic solution for the thermomechanical behavior of shape memory polymer (SMP) in large deformation, based on a thermo-viscoelastic constitutive model. The formulation presented in this paper is suitable for describing shape memory behaviors such as fixed-strain, stress-recovery and stress-free, strain-recovery, as well as for multiple shape memory effect in uniaxial and combined extension-torsion problems. To verify the results, a comparison has been carried out among the proposed formulation results and those of experiments and 3D finite element analysis outcomes. Compared to the finite element analysis, semi-analytical solutions are interesting due to their very low computational cost. It was observed that the solution time for the proposed method is much lower than the computational time needed for the FE analyses (around 1%). Therefore, the presented solution can be employed as an efficient tool for examining the effects of changing any of the material or geometrical parameters on smart structures consisting of SMP components under torsion-extension for their design and optimization, which involves a large number of simulations. Additionally, the proposed solution is suitable for calibrating material parameters in both uni-axial and 3D benchmark problem of torsion-extension.