Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 306

According to ( 3.69 ), the force factor is f S5 = 1.2362
and the equivalent tensile force is
Number of bending cycles and car trips:
The discarding number of bending cycles in simple bending with the durance
factor f N2 = 0.93 for the side deflection of 0.65 is

Then the number of trips from or to the ground floor is

1

Z A10 ¼ ¼ 243,000 :

3 1

649,000

1,163,000 þ

According to Fig. 3.82 for office buildings with 20 possible stops, the number
of trips from or to the ground floor is expected to be 43 % of the total number of
trips. Then the total number of trips at which not more than 10 % of the wire ropes
has to be discarded is

Z A10 ; tot ¼ Z A10

0 : 43 ¼ 565,000

and the mean total number of trips

Z Atot ¼ 1,284,000 :

The loss of endurance by the rope twisting is still unknown. For the present
twisting distance a relative small endurance loss has to be expected. For elevators
it is not necessary to consider the force limits.

Example 3.13 Mining installation with traction sheave

Data:
Mass of pay load Q = 10,000 kg
Mass of cage of attachment F = 7,000 kg
Force of moving resistance K = 8kN
Hoisting distance L = 1,000 m
Warr.-Seale 6 9 36-FC - sZ
Rope diameter d = 60 mm
Number of ropes n = 1
Mass of the rope s = 13,200 kg
Mass of the balance rope s b = 13,200 kg
Nominal strength R 0 = 1,770 N/mm 2
Speed v = 15 m/s

strongest
stressed
rope peice

F

F

Q