Modeling of strain rate effect on the pseudoelastic behavior of NiTi SMA using a simple thermomechanical coupling model

Abstract

NiTi SMA represents a popular group of metals with interesting properties like pseudoelasticity and a high energy dissipative capacity. Indeed, NiTi alloys, presents an interesting damping capacity due to solid-solid phase transformation. Such characteristics allow them to be used in many civil engineering fields mainly as actuators and damping devices. However, because of their complex behavior, the design process of these applications seems to be complicated and consequently, needs to build accuracy numerical models. One of these already existing models is the micromechanical Likhachev model. It seems to be very attractive thanks to its general formulation, numerical efficiency and model parameters relatively easy to determine. This paper concerns the numerical simulation of the pseudoelasticity behavior of NiTi wires dedicated to the application of damping devices, at different stress and strain rates. A thermomechanical coupling is introduced in the Likhachev formulation in order to simulate the thermomechanical behavior of NiTi under strain control. In this paper the model is adapted to a strain-controlled formulation, and 1D simulation is achieved using FORTRAN code. Parameters model are identified thanks to SiDoLo software and the corresponding results are presented and discussed. A good agreement with experimental data is found for the two formulations.