Numerical simulation for stress-induced phase transformation of SMAs tube under tension

Recent uniaxial tension tests have shown that stress-induced phase transformation in NiTi SMAs tubes can lead to helical-type localized deformation and propagation phenomena. Based on detailed experimental observation and possible deformation mechanism, a trilinear stress-strain relationship with intrinsic strain softening is employed to represent the material constitutive behavior in this paper, and a 3-D finite deformation simulation is performed to model the tube under tension by using nonlinear FEM. The simulations successfully reproduce the nucleation and evolution of the helical-type martensite band during stress-induced transformation observed in the experiments.