Development of Friction Damper With Displacement Dependent Variable Damping Force Characteristics

Abstract

A friction damper with displacement dependent variable damping force characteristics was developed. The damper was designed to decrease damping force when damper displacement exceeded a predetermined value. Therefore, the damper is ideal for aseismic retrofit of existing skyscraper buildings in preparation for long-period earthquake ground motions expected to occur in the near future. Dynamic loading tests were conducted on a full-scale steel frame with a brace-type variable friction damper to verify the damper performance. The damper exhibited on-target characteristics, stable performance, and a high endurance capacity under cyclic loadings.

Energy response of a passive variable friction damper and numerical simulation on the control effects for high‐rise buildings

“…The present experiments expanded on previous studies on the elemental testing and the full‐scale loading testing of VFD specimens 43,44 by providing detailed insight into the function and energy response behavior of the VFD devices. The elemental test was carried out using an elemental specimen to grasp the basic characteristics of the VFD units, including their operation behavior.…”

“…Photographs of the elemental test specimen consisting of two variable friction damper (VFD) units: (a) front view 43 and (b) side view…”

“…Results of the elemental test (triangle waves, loading amplitude ±40 mm, maximum loading velocity 3 cm/s, five cycles): (a) time history of the damper displacement; (b) time history of the average bolt axial force; (c) average bolt axial force plotted against damper displacement (steady portion); (d) time history of the damper force; and (e) hysteresis loop of the damper 43 (steady portion)…”

“…Elevation drawing of the loading system incorporating the brace‐type variable friction damper (VFD) specimen for full‐scale testing 43 …”

“…Photographs of the full‐scale testing setup: (a) dynamic loading system 44 and (b) variable friction damper (VFD) specimen…”