"Damage identification in suspended cables through dynamic measures"

Structural cables in cable-stayed systems are subjected to potential damage, mainly due to fatigue phenomena and galvanic corrosion. The paper deals with the analysis of damage effects on the static and dynamic behaviour of suspended cables. To this purpose, a continuous monodimensional model of a damaged cable is presented, including geometric nonlinearities. The damage is described as a reduction of the cable cross section, and defined through its intensity, extension and position. The sensitivity of the system spectral properties with respect to the three damage parameters is analyzed thanks to the closed-form solution of the eigenproblem associated to the transversal and longitudinal motion. In particular, the transversal frequencies are found to be appreciably sensitive to the damage intensity and extension. A procedure, based on the comparison between the model eigenfrequencies and frequency measures obtained from the experimental dynamic response of in service cables, is used to identify the damage parameters. Its efficiency is successfully verified on pseudo-experimental data