WSEAS Transactions on Applied and Theoretical Mechanics
Print ISSN: 1991-8747, E-ISSN: 2224-3429
Volume 8, 2013
Wire Rope Springs for Passive Vibration Control of a Light Steel Structure
Authors: ,
Abstract: The restoring force of wire rope springs is generated by the wire ropes deformation that, at the same time, dissipates energy due to the friction forces arising between its wires during the deformation of the rope. In this paper, the dynamic behavior of a light structure isolated by means of isolators, constituted by wire rope springs and a ball transfer unit, is investigated; the adopted structure simulates objects sensitive to seismic accelerations, like works of arts or cabinets containing electromechanical devices whose functioning must be ensured during seismic events. In the first part of the paper the system dynamic characteristics are evaluated by means of an experimental modal analysis conducted on a shaking table by assigning different laws of motion to its moving platform. The frequency response has been obtained through mono-frequential and multi-frequential excitations; the platform has been also moved with laws deduced from accelerograms recorded during seismic events to evaluate its insulation efficiency. The modal analysis has shown the frequency range where the proposed isolation system produces a beneficial action for the specific passive vibration control application. Experimental data have been used to validate a numerical model that can be adopted to simulate operating conditions different from those of the experimental tests; the results of several simulation are reported to highlight the influence of some parameters on the system dynamic behavior.
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Keywords: Wire rope springs, shaking table tests, experimental modal analysis, nonlinear dynamics, vibration control