Hysteresis characteristics and parameter influence analysis of SMA self-centering rotational friction damper

Abstract:

To reduce the residual deformation of structures under seismic loading, a self-centering rotary friction damper (SMA-SRFD) based on shape memory alloy (SMA) bolts was proposed. The basic structure and working principle of the damper were introduced. Material property tests of SMA bolts were conducted, and theoretical analysis of the force performance of the bolts and SMA-SRFD was carried out. The results were compared with those from finite element analysis to verify the accuracy of the theoretical formulas used. A three-dimensional finite element model of the SMA-SRFD was established, and a parametric analysis was performed with the rotation angle of the frictional inclined plane, the friction coefficient, and the pre-tension of the SMA bolts as variables. The results show that the stress-strain curve of the SMA bolt exhibits a typical “flag” shape, indicating good energy dissipation and self-centering capabilities. The results of theoretical analysis and numerical simulation of the SMA-SRFD are consistent, both accurately reflecting the force process of the damper. Increasing the inclination angle of the inclined plane enhances the load-bearing capacity and equivalent stiffness of the SMA-SRFD, but the energy dissipation and damping ratio decrease. By increasing the coefficient of friction between the contact surfaces, the energy dissipation, equivalent stiffness, and equivalent damping ratio of the SMA-SRFD all increase, while the self-centering capability weakens. As the pre-tension of the SMA bolts increases, the maximum load-bearing capacity of the SMA-SRFD remains essentially the same, while the deformation decreases slightly. Moreover, the different pre-tensions to the SMA bolts does not significantly change the hysteresis performance of the damper.