LAUSR

Abstract A novel hybrid frictional metallic passive damper is introduced in this study. The Piston Hybrid Frictional Metallic Damper (PHFMD) is equipped with friction pads and steel variable-width strips as energy dissipating parts. These parts are put in the final assembly of the damper with the aid of connectors and rigid parts. The PHFMD characterizing parameters have been determined based on comprehensive experiments. At first, a setup is designed to test the response of friction pads at different clamping torque. The experimental data approves the applicability of the pads in terms of the stability of their hysteretic response. At the second stage, cyclic loads have been applied to three different PHFMD specimens. These specimens are specially designed to exhibit single-phase (PHFMD-A and PHFMD-B) and dual-phase (PHFMD-C) response when subjected to displacements. In the case of dual-phase response, the first phase’s capacity will be activated in case of wind or light to moderate earthquake excitations. In case of severe earthquakes, the full capacity of the dual-phase damper will be mobilized to mitigate earthquake impact on the structure. The experimental results approve the significant performance of the dampers in fulfilling design goals. The performance parameters include the achievable cumulative displacement, dissipated energy, and effective equivalent viscous damping ratio. It is observed that all the specimens have endured accumulated displacement of over 2000 mm (reaching near 4000 mm for the PHFMD-C specimen) while dissipated a significant amount of energy. The specimens also have demonstrated significant viscous damping ratios in the range 45–55%. None of the dampers has shown any degradation or damage when subjected to standard loading protocol. In order to provide a means for the analysis, FE models of dampers have also been developed. Comparison of FE results and experimental data show remarkable agreement. Finally, FE-verified analytical relations are provided for the design purposes of single-phase and dual-phase PHFMDs.