Analysis and Test of Torque Balanced Electromechanical Mooring Cables

A method for stress and torque analysis of a steel armored Electromechanical mooring cable is presented and is compared with test results. The cable studied in this paper has an electrical core around which is helical wound two layers of armor. When the armor wires are loaded they develop torque and rotate. They also move radially; the amount of movement depends on the core hardness. This paper will limit itself to a soft core. Equations are developed to determine cable torque, torque unbalance, rotation, wire elongation, and stress. Empirical data is presented to determine cable modulus and elongation. Finally, this paper discusses actual torque balance and cable strength tests of electromechanical cables. Computed results are compared to test data for two cables. Very good agreement was achieved with test data in both cases.