Abstract
A stress-strain curve of a shape memory alloy varies during cyclic loading, since the martensite phases cannot completely transform into the austenite phase due to accumulating dislocations, mismatches of grain boundaries, etc. That is called the training effect. To duplicate this effect mathematically, the one-dimensional phase transformation model is applied, in which phases composed of the austenite and the residual matensite are introduced. To verify the validity of this model, cyclic tensile loading tests of a superelastic shape memory alloy wire are carried out and the measured stress-strain curves are compared to those obtained by calculation with the proposed model. The result shows that the proposed model can capture the gradual variation of the stress-strain curve for the first several cycles with reasonable accuracy.
