Assessment of tension–compression asymmetry of NiTi using circular bulge testing of thin plates

Tension–compression asymmetry in a polycrystalline superelastic NiTi thin sheet is studied by means of circular diaphragm bulging test and tensile tests. Tensile tests along the rolling and transverse directions allow evaluation of planar anisotropy. The equibiaxial tensile stress–strain curve at the centre of the bulge specimen is calculated from pressure and kinematical full field measurements. The deviatoric stress tensor for this stress state is identical to that of uniaxial compression in thickness. Asymmetric behaviour similar to in-plane tension–compression asymmetry is observed.