Experimental identification of cable damping parameters towards robust design against aeroelastic instability

Steel cables are lightly damped structural elements for which ambient loads may produce large amplitude oscillations, which may eventually determine fatigue ruptures. The dynamics of cables have been extensively explored in the literature and evidencewas given of the fundamental role played by structural damping in determining the quality of the vibration. Particularly, it was either numerically or experimentally observed that bifurcated solutions exist when modal damping ratios are sufficiently small. Provided this scenario, an accurate identification of the cable damping parameters is essential for robust design against ambient vibrations and for life cycle assessments. To this end, wavelet analysis is here applied in order to identify the damping parameters of a suspended cable model. The aim is to explore the robustness and the repeatability of the results with respect to different test conditions. Afterwards, the nonlinear forced harmonic vibrations of the system are numerically explored, devoting particular care to the role of damping uncertainties on the cable response. Finally, the use of a secondary tuned mass damper system is discussed as a way to increase the robustness against cable aeroelastic instability.