On the vibration control through mode coupling in a near-uniform chain-like structure using an inerter

Abstract

The tuned mass damper (TMD) is a classical device interesting for reducing deformations between DOFs without physically connecting them. However, it has a practical limit due to the increase in mass required for improving its performance. A building mass damper (BMD) uses mode coupling to make the upper substructure of a chain-like structure behave as a TMD for the lower substructure, which avoids adding mass to the structure. Unfortunately, near-uniform chain-like structures require isolation of the upper substructure for tuning the BMD, making it impractical for retrofitting existing structures since it is an in-series intervention. This paper proposes and evaluates using an inerter, instead of isolating the upper substructure, to control vibrations through mode coupling in a chain-like structure. From an analytical and numerical study, it was found a significant reduction of lower substructure deformations by implementing solely an inerter and a damper in the upper substructure. The inerter-based approach showed similar performance to the classical BMD with the advantage of being an in-parallel intervention. Therefore, this approach constitutes a practical retrofit to improve the dynamic behavior of existing structures with excessive deformations in a lower substructure whose functionality or esthetics would be compromised if control devices were installed in it.