Dynamic response analysis of viscoelastic coupling damper under cyclic loading

Viscoelastic coupling dampers (VCDs) are an effective passive energy-dissipation device for improving seismic performance in high-rise buildings. This study evaluates the cyclic response of natural-rubber-based VCDs under displacement amplitudes of 2–15 mm and loading frequencies of 0.1–0.5 Hz. Hysteresis loops were obtained from 20-cycle sinusoidal loading and were analysed to derive storage modulus (G1), loss modulus (G2), loss factor (η), energy dissipated per cycle (Ed), equivalent stiffness (Ke), and equivalent damping coefficient (Ce). The VCDs exhibited stable and repeatable loops, with loss factor ranging from 0.085 to 0.205, equivalent damping coefficient increasing up to 344.84 kNs/m, and energy dissipation increasing from 2.6 N·m at 2 mm to 155.8 N·m at 15 mm. Displacement produced clear strain-softening effects, whereas frequency influenced rate-dependent stiffening. These experimentally derived parameters are directly applicable for numerical modelling and seismic design systems.