Development of a novel Cu–Al–Mn SMA bolts-based self-centering wedge-shaped friction-viscoelastic composite damper

Abstract Conventional structural dampers are constrained by inherent limitations: viscoelastic dampers demonstrate low initial stiffness, reducing their effectiveness under wind loads and minor earthquakes; friction dampers provide considerable energy dissipation but often induce significant residual deformations; and self-centering dampers based on nickel–titanium shape memory alloys (Ni–Ti SMAs) effectively mitigate residual displacements yet are hindered by prohibitively high material costs, which restricts their widespread application. To holistically address these challenges, this study proposes a novel self-centering wedge-shaped friction and viscoelastic composite damper that incorporates cost-effective copper-based SMAs. Initially, the effects of solution treatment temperature and cyclic thermal loading on the mechanical behavior of Cu-based SMA bolts were systematically investigated. Subsequently, the configuration and working principle of the proposed damper were described in detail. Furthermore, quasi–static cyclic tests were conducted to assess its hysteretic behavior, self-centering capability, and energy dissipation characteristics. Finally, a comprehensive numerical investigation was performed to systematically quantify the influence of key parameters—including loading frequency, bolt preload, bolt diameter, wedge surface friction coefficient, and wedge slope height—on the damper’s cycle performance. The experimental and numerical results collectively indicate that bolt preload contributes to the most substantial enhancement in initial stiffness, with an increase of up to 585%. A critical transition in performance is observed at wedge slope heights between 8 mm and 10 mm. Although a higher friction coefficient improves the equivalent viscous damping ratio, it compromises the self-centering capability. Moreover, increased loading frequency enhances energy dissipation but leads to an increase in residual displacements.