LAUSR

Abstract One of the effective parameters on the characteristic response of the nickel-titanium (NiTi) shape memory alloy (SMA) is the employed loading mode during the uniaxial cycling. In this study, the uniaxial tensile tests are conducted under an extended number of mechanical cycles in order to investigate the effect of force control on the pseudoelastic response of the NiTi SMA. The results which are obtained under the force control are compared with the mixed (force/displacement) control counterpart. An evolutionary stress-strain pattern is observed during the 100 cycles of mechanical loading. Additionally, it is noticed that the residual strain and mechanical hysteresis area also show an evolutionary pattern. The observed evolutionary patterns are delineated in three regimes: (i) early evolution; (ii) approach to a nearly stable stage (transient); and (iii) stabilization stage. Furthermore, the in-situ digital image correlation (DIC) is applied to receive the meso-/micro-scale full-field strain measurements. Severe strain localization is observed under force-controlled tensile test during meso-,/micro-scale DIC analysis.