Free vibration of pseudoelastic NiTi wire: finite element modeling and numerical design

On account of the dissipative martensite phase transformation, NiTi shape memory alloy can exhibit large pseudoelastic deformation and high damping capacity, making it a promising candidate in engineering vibration control. The main objectives of this paper are twofold: to investigate the free vibration behavior of the NiTi wires and to design a NiTi wire-based vibration isolator to verify its effectiveness in vibration control. The free vibration system consists of a mass and two antagonistic NiTi wires; finite element simulation on this system is carried out. The material model used in the simulation is created by implementing a generalized SMA model into commercial software by means of a user-defined material subroutine. Uniaxial tensile tests on the pseudoelastic NiTi wires and cables were conducted to determine the model parameters. Parametric analysis of the vibration system shows that the mass affects the frequency, the initial deflection affects the dissipation of the vibration energy in the first few cycles, and the pre-strain decreases the stabilized amplitude. Finally, a NiTi-based vibration isolator is designed, which can dissipate 95% of the vibration energy in 0.3 second, showing good ability to recenter the device in a short time.