Thermomechanical Simulation of Uniaxial One-Way Shape Memory Effect of Ni-Ti Based SMAs by FEM

Shape memory alloys (SMAs) are smart metallic materials possessing special properties which consist of shape memory effect (SME) and superelasticity (SE). The application of SMAs in the field of civil engineering is comparatively new but increasing, especially in recent years. While SMAs are used for different purposes, one of their typical uses regarding SME is to prestress structural components as a strengthening approach. For decades, constitutive models of Ni-Ti based SMAs were proposed and developed. This work presents numerical simulations of SME by FEM. With a user-defined material subroutine (UMAT), some typical thermomechanical models were conducted in finite element software ABAQUS. Specifically, the uniaxial one-way shape memory effect of Ni-Ti based SMA wires was simulated, including the process of pretensioning and thermal activating (with displacement constraint). The stress-strain and stress-temperature relations of the process were obtained and recovery stresses were calculated. In future works, the simulation of SME may help investigate the prestress effect when it comes to the strengthening of structural components.