An experimental and theoretical investigation is carried out on a system consisting of a primary structure coupled with a passive/active autoparametric vibration absorber. The primary structure consists of a building-like mechanical structure with two rigid floors connected by flexible columns made from aluminium strips, while the vibration absorber consists of a cantilever beam with a PZT patch actuator cemented and actively controlled through an acquisition card installed on a PC running on a Matlab/Simulink platform. The overall system is then a coupled nonlinear oscillator subjected to sinusoidal excitation, obtained from an electromechanical shaker, in the neighborhood of its external and internal resonance. The addition of the PZT patch actuator to the cantilever beam absorber, cemented to the base of the beam, makes active the autoparametric vibration absorber, thus enabling the possibility to control the effective stiffness and damping associated to the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty.
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