Studying of the Behavior of Hybrid Friction-Yielding Damper under the Cyclic Loading

Abstract

Over the past decades, it has been done extensive studies on the plasticity development (stiffness) of the restrained bracing frames. One of the new methods is the use of metal rings as an energy loss (dissipations) among the intersection of braces. Previous studies have shown that the braces with a ring exhibit a stable hysteresis curve in cyclic loadings as well as losing energy that makes to decrease the force demand on its components. Although the performance of these dampers is predicted for the planned earthquakes (Seismic design of structures), but the elastic steel rings would be remained in the earthquakes less than this extent. In this study, there is a damper consisting of three steel rings as a parallel combination of springs which they are able to dissipate energy at two different levels of earthquake. In medial earthquakes (less than planned earthquake), it was modified a loop with a larger diameter (less stiffness), but in the case of planned earthquakes with internal yielded loops, dynamic characteristics of the structure would be modifies well. In order to study the behavior of this type of the dampers, the behavioral curves of the models are derived from the effect of round loads using the ANSYS finite element software. The behavioral curves showed that two levels of specific energy loss were obtained for two levels of seismic designs, and the results showed that the energy loss increases by adding of a second phase yielded damper to the first one considerably. Also, due to the addition of the yielded damper (steel ring) in specified displacement, the yielded damper shows a more stable behavior.