Experimental and numerical simulation analyses of a displacement-dependent self-centering variable friction damper

A displacement-dependent self-centering variable friction damper (DSVFD) was proposed to mitigate the residual displacement of structures following seismic events by utilizing the self-centering capabilities of a disc spring group and the energy dissipation features of a stepped friction plate. Cyclic loading tests coupled with finite element analyses were conducted to examine the impacts of the friction plate preload, loading displacement amplitude, and number of loading cycles on the damper's self-centering and energy dissipation behaviors. These findings suggest that increasing the friction plate preload improves the energy dissipation capacity of the damper, although it adversely affects the self-centering rate. Increasing the loading displacement significantly increased the energy dissipation, whereas increasing the number of loading cycles had a negligible effect on the performance. A comparison between the experimental results, considering various friction disc preloads, and the numerical simulations demonstrates a strong correlation. Further parametric analyses revealed that increasing the inclination angle of the friction plate increased the peak load, loading stiffness, and self-centering capability of the DSVFD. Additionally, an increase in the kinetic friction coefficient between the friction plates enhances energy dissipation but diminishes the self-centering ability of the damper.