An axi-symmetric FEM model of drum with multi-layer rope winding

Due to increasing demand of both the off-shore and the maritime industry there is an increased interest in the behaviour of the ropes in drums with multi-layer rope winding. In this paper an axi-symmetric FEM model of both the drum and the complete rope package is presented. All windings can be individually pre-stressed and can be in contact with each other and the drum (flange and barrel). The number of coils in a layer and the number of layers are parameterized. The model predicts the rope pressure division on the barrel as on the flanges and the final cable tension in all coils. Full scale strain gauge tests have been carried out on a 270 tonne 11 layer anchor winch with 1250 m rope, diameter 76 mm maximum break strength 425 tonnes. The stiffness properties (both lateral and axial) of the rope have been tested and used in the FEM model. The results of the FEM model and the strain gauge tests are compared and are in good agreement. With this FEM-model a more accurate pressure on the drum can be calculated. Any given load pattern and the stiffness properties of both the rope and the drum can be considered.

Author(s): W. van den Bos, C. de Ruiter and S. Maljaars