Abstract：In this paper, the thermomechanical coupling behavior at the mode I crack tip of NiTi shape memory alloy is numerically simulated and verified by experiments. A constitutive model including phase transformation and thermal mechanical coupling is established. The longitudinal strain, martensite volume fraction and temperature field near the crack tip are obtained by finite element calculation. The effective stress intensity factor at the crack tip was modified according to the martensitic transformation, and the effect of loading rate on the effective stress intensity shadow at the crack tip of shape memory alloy was revealed. Parametric study shows that with the increase of loading frequency, the temperature near the crack tip increases gradually, the martensitic transformation region decreases gradually, and the effective stress intensity factor decreases. The shape memory alloy shows toughening effect, which is helpful to slow down the crack growth. The results of this study have important reference significance for revealing the fatigue crack growth law of hyperelastic shape memory alloy under thermal mechanical coupling.
2022, Vol. 43 
