Wire Ropes Under Tensile Load - Wire Ropes: Tension, Endurance, Reliability - page 93

Table 2.4 Correction constants DE for round strand ropes with 6- and 8-strands of one, two and
three wire layers
Rope condition Rope core Correction constant

6-strands 8-strands

Wire layers Wire layers

1 2 3 1 2 3

New Fibre core 16 0 -1 14 -2 -3

Steel core 15 0 -1 -2 -17 -18

Ten times loaded Fibre core 11 0 -3 8 -3 -6

Steel core 11 0 -2 0 -11 -13

Fibre core = NFC, SFC; steel core = IWRC, PWRC, ESWRC, EFWRC

Results:
From ( 2.50 ) and ( 2.52 )
E S (r lower , r upper ) = E S (100; 220) = 98 kN/mm 2
Alternative from tables:
From Table 2.3 the rope elasticity module for a rope IWRC + 6 9 19 is
E S (100; 200) = 107 kN/mm 2 and E S (100; 300) = 113 kN/mm 2 and as a middle

value E S (100; 220) = 108 kN/mm 2 .
From Table 2.4 the correction constant for 8-strand ropes is DE = -11 kN/mm 2 .
This means that with ( 2.53 ), the rope elasticity module for the wire rope
IWRC + 8 9 19 is E S (100; 250) = 110 - 11 = 97 kN/mm 2 . Nearly the same as
98 kN/mm 2 .
According to Table 2.1 , the standard deviation is s = 10 kN/mm 2 .

2.2.4 Waves and Vibrations

2.2.4.1 Longitudinal Waves

If a long wire rope receives a shock load, a tensile force wave (strain wave) moves
along the wire rope starting from the initial point of impact. The velocity of the
wave is

s E

q

c ¼ ð 2 : 54 Þ

with E for the elasticity module and q for the mass density. For a single wire with,
for example, E = 196,000 N/mm 2 = 196,000 9 10 6 N/m 2 and q = 7,800 kg/

m 3 = 7,800 N s 2 /m 4 the velocity of the wave is