Cyclic behavior of a web hourglass-shaped pin damper made of low-yield-strength steel: Experimental and numerical analyses

Web hourglass-shaped pins fabricated from low-yield-strength steel (LYSWHPs) can be utilized as energy dissipation (ED) components in the connections of steel structures to effectively enhance ED and reduce damage to the primary structural components under intense earthquakes. First, quasi-static tests were carried out on three LYSWHP specimens made of LY225 steel; when bolted to its supporting plate, each exhibited a stable, suitable hysteretic response, excellent ED capacity, high ductility factor of 5.01-9.55, and excellent plastic deformation. Axial force effects and large plastic strains significantly increased the strengths of the LYSWHPs, with the maximum overstrength factor reaching 2.36. A finite-element analysis model was established in ABAQUS and confirmed against the behaviors of the test specimens to perform parametric analyses on individual and group LYSWHP models. The results demonstrated that the shape of the LYSWHP significantly affects its loadcarrying capacity, ED capacity, and failure mode; the shape factor and slenderness ratio of the ED segment should be within 0.375-0.75 and 2.75-4.25, respectively, to ensure the desired behavior. The number of LYSWHPs, supporting plate thickness, and LYSWHP shape significantly affect the hysteretic behavior of an LYSWHP group. When the supporting plate provides strong restraint, the ED capacity and ductility of each LYSWHP is fully developed, all cumulative damage is concentrated within the LYSWHPs while the supporting and loading plates remain elastic, and the group will exhibit ductile failure. The findings of this study provide reference for the practical application of LYSWHPs in building structures.