A new method of termination for heavy-duty synthetic rope fibres.

Abstract

Termination of heavy-duty synthetic fibre ropes has long been an issue of concern in marine environments. Recent serious rope accidents and new requirements for lighter ropes with better performance in mooring lines have encouraged industry to look for new methods for increasing line performance using existing ropes. One way of increasing rope performance is to use efficient methods for rope termination. This is why the main objective of this study has been to investigate a new method for rope termination. Rope failure usually happens inside or very close to termination due to high stress concentration areas. The new method, "The Vaseghi Stress Relief Socket", has been proposed to improve the high stress concentration areas inside sockets and move failure points along the rope. The new method has increasedthe tensile performance of existing ropes up to 13%. It should also be addedthat the ropes in this study are mainly used in marine environmentsfor mooring oil platforms. Considering the results of the tensile and cycling tests, The Vaseghi Stress Relief Socket, proved a great potential for replacement of existing methods of termination e.g. the splice. It should also be noted that the reproduction of the socket termination is more consistent than that of other methods of termination. Tensile properties of ropes using `The Vaseghi Stress Relief Socket' were initially a matter of concern, for rope termination is the most important feature of ropes.In fact, if there is a termination failure in tensile tests, the rope will not be considered efficient for mooring purpose even though its other performancesare excellent. Load cycling was the second property that was considered. Acoustic Emission monitoring was performed to find out the relation between the load-extension behaviour of the rope using The Vaseghi stress Relief socket and the AE signals. Finally, the finite element modelling of socket helped to investigate the stress concentration areas in the socket to optimise the amount of the reinforcing material and identify the weak point areas in the socket, which could lead to further research studies for new designs.