Application and Performance Evaluation of Superelastic Shape Memory Alloys in Building Vibration Isolation Systems

In this study, the intrinsic model of Shape Memory Alloys (SMA) is employed to facilitate a comprehensive analysis of the phase transition process, encapsulating the evolution of stress and strain across varying temperatures. The martensite volume fraction is quantitatively described using a cosine function, culminating in the formulation of a cosine-type SMA phase transition equation. This model enables the simulation of superelasticity, shape memory effects, and the elastic-thermal behavior of SMA by varying the loading conditions. This approach allows for an assessment of how different material parameters influence SMA properties. Notably, the results highlight that the heating temperature significantly affects the hyperelastic energy dissipation properties of SMA. The energy dissipation coefficient increased by 15.3% when the temperature was increased from 350 to 550 and decreased by 36.3% when the temperature was increased from 550 to 650. The peak values of top acceleration and interstorey displacement of the SMA-isolated structure were 0.826 m/s² and 0.641 mm for EL-centro waves at 7+ seismic intensities. The values of non-isolated were 1.151 m/s², 0.856 mm. 10 ground shaking, the SMA braced structure relative to the steel frame structure on the maximum peak inter-story displacement angle and the structure of the top layer of the permanent displacement, have different degrees of reduction. Therefore, the SMA material possesses good damping performance in the seismic isolation system.