Wire Ropes Under Tensile Load - Wire Ropes: Tension, Endurance, Reliability - page 133

In the present case, the twist angle from the simplified ( 2.91 ) is precise enough.
The maximum stresses on both of the rope ends can then be calculated with the
twist angles from ( 2.91a ) and ( 2.91b ).
By analysing the equations, it will be found that the stresses are independent
from the rope diameter and depend only on:

• The constants involved (Tables 1.8 , 1.9 and 2.6 ) the rope construction being
considered
• The wire rope length L and
• The specific tensile force S 0 /d 2 on the lower rope end.

Example 2.14b Wire stresses caused by twisting the rope
Wire ropes supported non-rotated at both ends, continuation of Example 2.11.
The data of Example 2.11 is again valid. Further data of the Warrington rope being
considered has been taken from Tables 1.8 , 1.9 and 2.6 . The rope lay angles are
a ¼ a 3 ; 1 ¼ 15 b ¼ b 1 ¼ 20 : and

Data:
rope construction Warrington FC

number of strands 8

lay direction sZ

rope diameter d = 16 mm

rope length L = 500 m

tensile force, lower rope end S = 10 kN

twist angle, lower rope end x = 178/100d

tensile force, upper rope end S = 14,35 kN

twist angle, upper rope end x = -164/100d

Results: for the lower rope end
Wire layer 0 1 2 3

Torsional stress s -51 -60 -61 -46

Longitudinal stress from rope twist r rot 101 55 -38 -60

Longitudinal stress from the rope force r S 137 135 132 131

Resulting longitudinal wire stress r res 238 191 94 71

Results: for the upper rope end
Wire layer 0 1 2 3

Torsional stress s 57 55 56 42

Longitudinal stress from rope twist r rot -94 -52 35 56

Longitudinal stress from the rope force r S 197 194 189 188

Resulting longitudinal wire stress r res 103 143 224 244