Abstract：Shape memory alloys (SMA) are a class of novel functional materials, used as both actuators and sensors, possessing unique thermomechanical behaviors such as shape memory effect (SME), superelasticity and high damping property, et al, which make them become perfect candidates for structural vibration control in civil engineering. This paper presents a study of the dynamic behavior and strain-rate-dependent constitutive model of superelastic NiTi SMA wires. Cyclic tensile tests on NiTi SMA wires with different stain rates were carried out to assess their dynamic properties. The equations that were used to describe the relationship between the stress increments and the strain rates were proposed. Base on the experimental data, an improved SMA constitutive model that can capture the strain-rate-dependent property was presented. To certify the validity and suitability of the improved SMA model, the comparisons between the numerical results and experimental data were made. The results show that the mechanical behaviors of NiTi SMA wires, including energy dissipation per cycle, secant stiffness and equivalent damping rate, initially increase with an increasing of the strain rate, but tend to be stable when strain rate is greater than 1.0×10-3/s. The numerical results and the experimental data are in good agreement, which indicate that the improve model, to a certain extent, can describe the strain rate dependent property of NiTi SMA wires.
2011, Vol. 32 
