Abstract Summary
Quasi-zero stiffness (QZS) isolators exploit the kinematic nonlinearity to increase the vibration attenuation with respect to a linear suspension. This paper presents an experimental study on a quasi-zero stiffness QZS isolator under base excitations. Stepped-sine tests have been performed to characterize the system and determine the isolator transmissibility. The system parameter identification has been carried out by fitting a model, based on the Duffing equation with viscous damping and dry friction, to the experimental data. Then, the isolator performance was verified under realistic earthquake signals. A satisfactory acceleration attenuation can be observed from the analysis of the time histories whilst a non-negligible presence of dry friction, leading to stick-slip phenomena and affecting the activation of the isolator at low frequencies, has been observed.
