Analysis of a shape memory alloy plate with a circular hole subjected to biaxial tension

In order to study the superelasticity of porous SMAs under complex loading, a thermo-mechanical model has been used to simulate the stress distribution and the phase transformation in the vicinity of the hole. The plate is in the austenitic phase prior to loading. However, as a result of tensile loading, stress-induced martensite forms, beginning from the boundary of the hole and extending into the interior, as the load continues to increase. The proportional loading is applied with different loading rates R. with the increasing of the loading rates, the regions of pure martensite around the hole increase. With the increasing of the 2-direction loading level, the stress-strain loops of the 1-direction descend, the critical stresses required for the martensitic transformation decrease and the slopes of the upper plateau in the stress-strain curves decline. Simultaneously, the initial surface of phase transformation under biaxial loading in the space (σ₁₁, σ₁₂) has been determined.