Cyclic behavior of a shape-optimized dumbbell-type combined slit damper with phased yielding characteristic

Abstract

This paper proposed a shape-optimized dumbbell-type combined slit damper (SDCSD) that enables phased yielding. In SDCSD, the shape-optimized dumbbell-type energy dissipation element contributes to the elimination of stress concentration, while the phased yielding characteristic reduce the adverse effect of damage accumulation. The calculation method of mechanical properties of dumbbell-type energy dissipation element (EDE) and the working mechanism of SDCSD are introduced. Two different configurations of SDCSD were designed, including double dumbbell-type combined slit damper (DDCD) and stiffened dumbbell-type combined slit damper (SDCD). Quasi-static test on five specimens were carried out to discuss the effect of shape optimization, phased yielding mechanism and the mechanical properties of SDCSD. Additionally, numerical simulations were performed to further investigate the factors affecting the mechanical properties of the SDCD. The factors include the shape parameters (α and β), the thickness of the stiffening ribs (γ), the yield load ratio (Ry) and the height-to-thickness ratio (Rh). Based on the results of numerical simulation, the modified formula for calculating the mechanical properties of SDCD were presented. The results indicate that the dumbbell-type EDE obtains a more uniform stress distribution and higher material utilization. The stiffened dumbbell-type plate outperforms the conventional dumbbell-type plate in terms of hysteretic stability and energy dissipation. Both DDCD and SDCD could achieve the expected phased yielding, and DDCD provides superior loading and energy dissipation capacity. Moreover, the dumbbell-type EDE provides excellent energy dissipation when α is taken as 0.1 or 0.2 and β is taken as 0.3–0.5 or 0.5–0.6. The out-of-plane deformation of the dumbbell-type EDE is minimized when γ is taken as 0.5. It is recommended that the Ry and Rh of SDCD should be taken as 0.5 and 30–44, respectively. Besides, the modified formula reduces the maximum calculation error of mechanical properties from 49.99% to 23.53% and is considered to be applicable to the design of SDCD.