On the modelling of the hysteretic behaviour of wire rope isolators

Wire Rope Isolators are made of two parallel retaining plates, connected through metallic wire ropes. Due to their good performances as vibration isolators, and shock absorbers, these devices have been widely employed in industrial applications. The dynamic behaviour of Wire Rope Isolators is strongly affected by both geometric and material non-linearities, mainly due to the peculiar hysteretic bending behaviour of metallic ropes. In this work a typical approach to characterize the hysteretic behaviour of wire rope isolators, based on a semi-empirical phenomenological model, is compared to a different approach based on a beam-like description of the wire rope and on a nonlinear formulation of the cross sections cyclic bending behaviour. The hysteretic cross-sectional model is then implemented within a corotational beam finite element, to fully account for the geometric non-linearities which characterize the response of the device. The performance of the proposed models are assessed through a comparison with the results of a well documented experimental test.