Nonlinear dynamics of cable stays. Part 2: stochastic cable support excitation

In this paper, an extensive behavioural study of cable vibrations, induced by in-plane stochastic cable-stayed structural vibrations, is made. Finite element modelling (FEM) and analysis (FEA) is used to determine in-plane and out-of-plane cable displacements induced by stochastic cable end displacements. The effects of stochastic cable support displacements, with abrupt and gradual transients, are studied. Regions of large-amplitude cable vibrations, induced by stochastic cable end displacements, are compared with those found from sinusoidal cable end displacements. The results show that, together with important similarities in cable response, there are also important differences in cable response between sinusoidal and stochastic cable support excitation. Differences in cable response amplitudes are found and discussed. It is also found that “cable-stiffening” occurs, for specific cable excitation parameters, as it does for sinusoidal cable support excitation, but to a lesser extent. Throughout the analyses, maximum cable stresses are calculated and, in some cases, are found to be near that required for cable material yielding.