While the method of brooming when steel wire rope is used is standard, regardless of rope construction or grade of steel, the method of opening the various segments of the rope to form a broom and the extent to which this is done is variable, depending on rope construction and fibre type. It is rarely necessary, or advisable to open down to the individual fibre level.
However, fibre rope behaves in a very different way when socketed than a steel wire rope. The wires inside the resin cone have the capability of transferring load along the full length of the resin cone, whereas, the load transfer ability of the fibres is only in the front 20/25mm of the resin cone. This produces tremendous stresses within this area and the resin cone stretches and wants to shear in the centre of the cone. This is because the fibres held in the outer part of the cone are less mobile due to friction and compression at the interface of the resin cone and the socket. Given the low stretch of aramid and other high strength ropes it means that the fibres on the outside of the rope will break and this breakage will continue progressively into the centre of the rope. The fibre never slips within the resin and failure always occurs at the neck of the socket.
Having said all this, our experience has shown that fibre ropes up to about 10mm in diameter will give excellent results with almost total disregard to the internal geometry of the socket. Above this diameter the achievable breaking load is progressively degraded until with very large diameter ropes the breaking strength is reduced to about 70% of M.B.L.
There are in existence a couple of patents which perform by splitting larger ropes into several ‘smaller ropes’ within the actual socket basket. Despite some extravagant claims for these two methods they are not 100% effective but they do improve the efficiency of socketed termination.