Experimental and Numerical Study of NiTi Holey Plates Loaded In Tension

We present results of the first experimental and numerical study of NiTi holey plates in superelastic state. Ti-50.8at% rectangular plates of 110mm x 29.5mm in dimension and 0.1 mm and 1.5 mm in thickness are used for tensile testing and for simulation. Electrical discharge machining (EDM) was used to machine tensile specimens and to cut circular holes of different diameters in the holey plates.

The holey plates samples were loaded in uniaxial tension along the length direction at room temperature. A special apparatus was applied to contain the out-of plane displacements in order to avoid buckling. The rate of deformation is sufficiently low to avoid thermal-mechanical coupling. The 3D displacement field on the sample surface was recorded by means of 3D digital image correlation method (Aramis software) , which also calculates the associated surface strain fields.

Essential material property parameters are extracted from the tensile experiments for simulation. Other remaining parameters required are selected from previous experiences or the literature. Simulation of the tensile deformation behaviour of the holey-plates was conducted by means of finite element simulation based on a elasto-hysteretic tensorial model. Findings of the simulation were validated by comparison with the experimental data.