Mechanical behavior of submarine cable under coupled tension, torsion and compressive loads

Developing an offshore wind farms, the submarine cables are required as power transmission media to connect offshore wind farms and onshore substations. Axial forces are one of the main causes of the damage to the submarine cables which consist of spiral armor, sheath, insulation and conductors. In addition to the axial elongation when the cable was subjected to tensile loads, the helical armor also produces torque and the coupled tensile and torsional mechanical properties of the submarine cable should be analyzed. In a deep water environment, the effect of water pressure on cable stiffness is important and seldom investigation was made in the past. This paper studied in detail the mechanical behavior of submarine cables under coupled tensile, torsional and compressive loads. When the cable is located 4000 m below sea level, the coupled tensile, torsional and compressive loads may reduce the tensile stiffness as a whole to 30%. The coupling effects of tensile, torsional and compressive loads, therefore, must be carefully considered in analysis and design of the submarine cables.