Resettable inertance inerter: A semiactive control device for energy absorption

GARRIDO, HERNÁN; CURADELLI, OSCAR; AMBROSINI, DANIEL

STRUCTURAL CONTROL & HEALTH MONITORING

JOHN WILEY & SONS LTD

Año: 2019

1545-2255

Semiactive control systems are based on formerly passive mechanical deviceswhose characteristics are adjusted in real time by active means. Theycan be classified into variable-damping dampers, variable-stiffness springs,and variable-inertance inerters. Similarly to the case of ?variable-stiffness,?two possibilities are devised for inerters: ?independently-variable inertance,?where inertance can increase or decrease continuously at any instant oftime, and ?resettable-inertance,? where it can increase only at instantswhere relative velocity is zero. By duality with resettable-stiffness springs, aresettable-inertance inerter (RII) is composed of an inerter that can suddenlybe disconnected from the vibrating system and blocked in order to eliminatekinetic energy. Studies on ?independently-variable inertance? have been carriedout recently, but there are still no studies on ?resettable inertance.? This paperpresents an analytical numerical study on RII, for an energy-based control law,through the mathematical model of a mechanical implementation. By simula-tion of a numerical example that considers a SDOF system with three differentdevices, the performance is demonstrated for energy absorption and vibrationreduction. Moreover, closed-form expressions for the equivalent-linear iner-tance, stiffness, and damping are found for the resettable devices and validatedthrough the numerical example. Main conclusion is that RII adds equivalentdamping without dynamically stiffening the structure. Besides, the absorbedenergy can be dissipated and/or harvested in time intervals in which the RII isuncoupled from the structure.