The Nested-Eccentric-Shells Damper with an Improved Approach to Increasing Hysteresis Behavior

Abstract

In this study, by the concept of control structures, a new shell configuration is designed for steel energy dissipative devices. This device is proposed for the protection of structures against earthquake forces. This device is named a nested-eccentric-shells damper (NESD). This damper is made of a large cylindrical shell that surrounded three small cylindrical shells. The conventional methods of welding or metal casting can be applied in constructing the NESD. The configuration of the shell-type components is designed in such a way that to be able as a combination of series and parallel springs. To assess the performance of this damper, numerical analysis, and full-scale testing are applied. Hysteretic loops obtained from the analysis with highly ductile performance are applied to determine the behavior of this proposed damper. The results indicate that the nested-eccentric-shells damper is of a stable behavior in hysteretic loops, and can provide appropriate damped energy subject to cyclic loading. However, to improve the performance and interaction of the internal members of this damper, a thickness ratio modification is proposed for the inner shells. The effectiveness and the usefulness of this modification in the numerical analysis have been proven in this study. © 2021, Amirkabir University of Technology. All rights reserved.