Wire Ropes Under Tensile Load - Wire Ropes: Tension, Endurance, Reliability - page 166

Fig. 2.49 Application of the
termination factor f T or the
rope length factor f L

2.6.5.2 Rope Terminations

The number of load cycles will be reduced if rope terminations other than resin
sockets are used. For ropes with these terminations, the number of load cycles is
normally

N cTerm ¼ f T N c ; 60 for f T ltf L ð 2 : 109a Þ

with the endurance factor f T for the termination taken from Table 2.12 (still from a
very small database) and with the number of load cycles N c,60 for ropes with resin
sockets and the rope length L ¼ 60d :
However for very long ropes it may be that the wire rope does not fail in the
termination region but on the free rope length. In that case—when the endurance
factor f T is bigger than the endurance factor f L for the rope length—the number of
load cycles is

N cTerm ¼ f T N c ; 60 for f T [ f : ð 2 : 109b Þ

From the both endurance factors f T and f L the smaller one has to be used, Fig. 2.49 .

2.7 Dimensioning Stay Wire Ropes

Stay wire ropes have to be dimensioned in such a way that they can stand up to
extreme forces which only occur rarely, be sufficiently durable in case of fluctu-
ating forces and have safe discard criteria. These safety limits are characterised by:

• Extreme forces
• Fluctuating forces
• Discard criteria