Experimental Characterization and Identification of the Shear Hysteretic Behavior of a Helical Wire Rope Isolator

The experimental characterization of a helical wire rope isolator and the identification of its asymmetric hysteretic behavior along the shear direction is illustrated. The restoring force time histories and the asymmetric force-displacement hysteresis loops are identified by using two different models: a differential one, obtained by a generalization the Bouc–Wen model, and an exponential one, denominated Vaiana–Rosati model. The accuracy of the identifications are quantified according to the mean square error between the experimental and the simulated curves. Finally, the frequency response curves of a one degree of freedom oscillator connected to the ground with the restoring forces provided by the two models are computed showing the dynamical features of the device and paving the way to a future experimental validation.