Global Responses of Exposed and Suspended Submarine Cables Due to Anchor Dragging

Abstract

Anchor damage is one of the main risk factors for the safe operation of submarine cables. Additionally, due to a scour effect induced by seabed currents, submarine cables are prone to exposure or even suspension, increasing the risk of being dragged by anchors. Therefore, it is necessary to study the global response of exposed and suspended submarine cables subjected to anchor dragging. In this study, the tensile and bending stiffnesses of submarine cables are calculated by theoretical methods, and the accuracy of these calculations is verified by establishing a detailed finite element model. Then, the mechanical properties of the submarine cables are equivalently modeled using beam elements, and a large-scale finite element model for exposed and suspended cables under anchor dragging is established. Considering different dragging forces, exposed lengths, spanning lengths, and spanning heights, the overall deformation and mechanical responses of exposed and suspended cables are analyzed separately. The results show that under dragging forces, axial forces are uniformly distributed along exposed and suspended segments, while bending moments concentrate at the central hooking area and the ends of exposed and suspended segments. The influence of dragging force, exposed length, spanning length, and spanning height on the stress and deformation of submarine cables is significant. The results can be used for submarine cable damage assessments caused by anchor dragging.

Keywords

• submarine cable
• anchor dragging
• exposed length
• spanning length
• spanning height