Multiaxial shape memory effect of thermo-induced shape memory polyurethane under proportional tension-torsion loading

Abstract

Shape memory behavior of thermo-induced shape memory polyurethane (TSMPU) under proportionally multiaxial loading is investigated experimentally. The shape memory effect is discussed under different axial and torsional loading angles. By comparing the equivalent stress-equivalent strain curves under different loading angles, it is found that the difference in thermo-mechanical behavior is mainly reflected in the shape memory effect. The equivalent characteristic quantities describing the shape memory effect are extracted from the experimental results. By analyzing their evolutions in the strain and stress spaces, it is found that the shape memory effect shows obvious anisotropy under different loading angles, i.e. the equivalent recovery rate of TSMPU increases with the increase of the loading angles. These results are helpful to establish a thermo-mechanical constitutive model for describing the shape memory effect under multiaxial loading.