Performance Assessment of Newly Developed Quasi-Zero Stiffness Damper (QZSD) for Seismic Protection of Steel Frame Structures

This paper presents a new design method to develop an energy-dissipating device and investigates its performance in seismic protection of steel frame structures. The proposed device leverages the concept of quasi-zero stiffness (QZS), thus called quasi-zero stiffness damper (QZSD). The QZSD is made of two anti-symmetrically arranged unit cells, each with a flapper system that provides negative stiffness (NS), and semicircular arches to produce positive stiffness (PS) under axial loads. This combined configuration of NS and PS elements attains QZS mechanical property for the unit cell. The force-displacement relationship of the unit cell is analyzed analytically for various stiffness ratios and geometrical parameters. Then finite element model (FEM) is developed to simulate and analyze its static and cyclic responses. Numerical results demonstrated that the anticipated device exhibits sufficient ductility, effective energy absorption capacity and stable hysteretic behavior with no rapid stiffness or strength loss. Comparisons with other metallic dampers highlight the superior performance of the QZSD in terms of yielding force, equivalent damping coefficient (EDC) ratio and total energy dissipation. Additionally, the design ensures compatibility with present structures without altering current construction and design practices.