Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 301

Both of the discard limiting forces are—as they should be—greater than the
rope tensile force S = 30 kN.

Optimal rope diameter:
According to the Eq. ( 3.73 ) and the constants c 0 listed in Table 3.19 , the
optimal rope diameter is

q

D S

p

d opt ¼ c 0 :

simple bending:

combined fluctuating tension and bending:

reverse bending:

A common optimal rope diameter can be calculated using ( 3.95 ) for the dif-
ferent numbers of loading elements w.

Example 3.9 Load collective for rope in simple bending

Data:

rel. part u i rel. tensile force k i = S i /S N

0.5 0.05

0.2 0.4

0.1 0.6

0.1 0.8

0.1 1.0

Discarding number of working cycles Z A
Rope class WS
Rope core WRC

Diameter ratio D/d = 25

The exponent p is after Eq. ( 3.93b ) with the constants of Table 3.14

¼ ð 1 : 588 2 : 577 lg 25 Þ ¼2.014

lg D
d

p ¼ b 1 þ b 3

With Eq. ( 3.93a ) the collective factor is