An Inerter-Based Dynamic Vibration Absorber with Concurrently Enhanced Energy Harvesting and Motion Control Performances Under Broadband Stochastic Excitation via Inertance Amplification

This paper examines the performance of a regenerative dynamic vibration absorber, dubbed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI), for vibration suppression and energy harvesting in white noise excited damped linear primary structures. Single-degree-of-freedom (SDOF) structures under force and base excitations are studied as well as multi-degree-of-freedom (MDOF) structures under correlated random forces. The EH-TMDI includes an electromagnetic motor (EM), behaving as a shunt damper, sandwiched between a secondary mass and an inerter element connected in series. The latter element resists relative acceleration through a constant termed inertance which is readily scalable in actual inerter devices. In this regard, attention is herein focused on gauging the available energy for harvesting by the EM and the displacement variance of the primary structure as the inertance increases through comprehensive parametric investigations. This is supported by adopting inertance-dependent tuning formulae for the EH-TMDI stiffness and damping properties and closed-form expressions for the response of white-noise excited EH-TMDI-equipped SDOF and MDOF systems derived through random vibration theory. It is found that lightweight EH-TMDIs, having 1% the mass of the primary structure, achieve simultaneously improved vibration suppression and energy harvesting performance as inertance amplifies. For SDOF structures with grounded inerter, the improvement rate is higher for reduced inherent structural damping and increased EM shunt damping. For MDOF structures with non-grounded inerter, improvement rate is higher as the primary structure flexibility between the two EH-TMDI attachment points increases.