Optimal design of dynamic vibration absorbers with series grounded inerter-damper

Passive dynamic vibration absorbers (DVAs) are widely used in structural vibration suppression with constant demand for higher efficiency in DVA designs. The inerter, which exhibits inertial amplification effects, is often used with springs and/or dampers in DVA designs. In existing research, a DVA with a parallel connection between an inerter and a damper demonstrates superior vibration suppression performance in structural systems when one end of the parallel connection is grounded. However, DVAs equipped with identical types and quantities of vibration suppression components may exhibit significant performance variations depending on the spatial arrangement of these components. To broaden the design scheme for DVAs, this paper investigates a novel inerter-based DVA that replaces the parallel connection with a series connection between an inerter and a damper, with one end similarly grounded. The connection node in the series configuration introduces an additional degree-of-freedom, necessitating explicit characterization and complicating subsequent dynamic analysis. This study investigates which of the two connection forms (parallel vs series) provides more effective vibration suppression under different excitation scenarios. By selecting appropriate optimization criteria based on external force characteristics and optimizing DVA parameters, the vibration suppression performance is systematically compared between the two DVAs with distinct connection forms. Results demonstrate that the series-configured DVA outperforms the parallel connection under random excitation, whereas the reverse is true for harmonic or impact excitations.