An efficient multi-scale methodology for the fatigue damage assessment of suspended cables under turbulent wind excitation

The paper presents a computationally efficient multi-scale methodology to address the fatigue life of suspended stranded cables under turbulent wind excitation. The cable is modeled as taut-string and the out-of-plane global dynamic response under buffeting load is obtained via the random vibration theory (macro-scale). Bending stresses are retrieved in a decoupled way by adopting a closed-form perturbation solution for the modal bending curvature within the boundary layers of the cable, leveraging the smallness of the dimensionless bending stiffness parameter (meso-scale). The stress state of each wire is reconstructed by employing a mechanical model of the composite cross-section of the cable (micro-scale). The accumulated fatigue damage of each wire is then computed according to Miner’s rule, and a simple expression of the cumulative wires micro-slip is proposed as a potential indicator of susceptibility to fretting fatigue. The influence of some design parameters on both indicators is addressed and the role of the nonlinear moment-curvature relationship on the short-term damage is highlighted.