Experiments on a Quasi-zero Stiffness Suspension for Passive Vibration Control

Experimental measurements on a quasi-zero stiffness (QZS) isolator under base excitations are reported. The setup is described and the QZS isolator is compared to a standard mass-spring system. The role of the geometric nonlinearities on the dynamic behavior is clear: the QZS isolator transmissibility shows a natural frequency reduction, and the system effectively suppresses the ground vibration about the fundamental frequency of the standard system. The QZS isolator performance has been tested also under real earthquake signals, showing satisfactory acceleration mitigation.