This paper outlines the method of predicting dynamic behavior of a snapping horizontal cable. Large dynamic tension build-up in rough seas may cause the total tension to become negative in certain parts of the cable. Since a cable has very low bending stiffness, it buckles instantly when under even a small negative tension. Since the transition to negative tension is continuous, the cable under ‘the influence’ of its own weight has acquired a certain free falling velocity by the time it goes slack. In order to get a model of a slack and then snapping cable, we assume that the buckling mechanism keeps the tension at near zero level until a positive value is regained, while its dynamic behavior is governed by the balance of inertia and drag forces that is, the clipping-off model. The comparisons between numerical model predictions and the existing experimental results are made.
Anchor chains of tension-leg single buoy mooring systems and oscillating chains anchored tangentially to the sea bed in deep water mooring system can go slack and then they are forced to go taut in a rapid motion. Goeller and Laura (1970), in a study of the dynamic response of stranded steel cables, found that maximum cable forces nine times the static payload weight in water were developed in snap condition (1). Kirk and Jain (1976), in their numerical simulations of anchor chain dynamics of tension-leg single buoy mooring system, found that the change in chain length was of the order of 1. 7m (the unstrained chain length = 152 m) which corresponds to an increase intension of 6.2MN, (2). Also, Fylling and Wold (1979) presented the comparison of cable: dynamics in their paper which included the cases when the dynamic force exceeded the static force (4).
